Genome-wide analysis of Tol2 transposon reintegration in zebrafish.

Science.gov (United States)

Kondrychyn, Igor; Garcia-Lecea, Marta; Emelyanov, Alexander; Parinov, Sergey; Korzh, Vladimir

2009-09-08

Tol2, a member of the hAT family of transposons, has become a useful tool for genetic manipulation of model animals, but information about its interactions with vertebrate genomes is still limited. Furthermore, published reports on Tol2 have mainly been based on random integration of the transposon system after co-injection of a plasmid DNA harboring the transposon and a transposase mRNA. It is important to understand how Tol2 would behave upon activation after integration into the genome. We performed a large-scale enhancer trap (ET) screen and generated 338 insertions of the Tol2 transposon-based ET cassette into the zebrafish genome. These insertions were generated by remobilizing the transposon from two different donor sites in two transgenic lines. We found that 39% of Tol2 insertions occurred in transcription units, mostly into introns. Analysis of the transposon target sites revealed no strict specificity at the DNA sequence level. However, Tol2 was prone to target AT-rich regions with weak palindromic consensus sequences centered at the insertion site. Our systematic analysis of sequential remobilizations of the Tol2 transposon from two independent sites within a vertebrate genome has revealed properties such as a tendency to integrate into transcription units and into AT-rich palindrome-like sequences. This information will influence the development of various applications involving DNA transposons and Tol2 in particular.

Microstructure and tribological properties of TiCu{sub 2}Al intermetallic compound coating

Energy Technology Data Exchange (ETDEWEB)

Guo Chun, E-mail: guochun@licp.cas.cn [State Key Laboratory of Solid Lubrication, Lanzhou Institute of Chemical Physics, Chinese Academy of Sciences, Lanzhou 730000 (China); Graduate University of Chinese Academy of Sciences, Beijing 100039 (China); Zhou Jiansong [State Key Laboratory of Solid Lubrication, Lanzhou Institute of Chemical Physics, Chinese Academy of Sciences, Lanzhou 730000 (China); Zhao Jierong; Wang Linqian; Yu Youjun [State Key Laboratory of Solid Lubrication, Lanzhou Institute of Chemical Physics, Chinese Academy of Sciences, Lanzhou 730000 (China); Graduate University of Chinese Academy of Sciences, Beijing 100039 (China); Chen Jianmin; Zhou Huidi [State Key Laboratory of Solid Lubrication, Lanzhou Institute of Chemical Physics, Chinese Academy of Sciences, Lanzhou 730000 (China)

2011-04-15

TiCu{sub 2}Al ternary intermetallic compound coating has been in situ synthesized successfully on pure Ti substrate by laser cladding. Tribological properties of the prepared TiCu{sub 2}Al intermetallic compound coating were systematically evaluated. It was found that the friction coefficient and wear rate was closely related to the normal load and sliding speed, i.e., the friction coefficient of the prepared TiCu{sub 2}Al intermetallic compound coating decreased with increasing normal load and sliding speed. The wear rate of the TiCu{sub 2}Al intermetallic compound coating decreased rapidly with increasing sliding speed, while the wear rate first increased and then decreased at normal load from 5 to 15 N.

Conventional and inverse magnetocaloric effect in Pr2CuSi3 and Gd2CuSi3 compounds

International Nuclear Information System (INIS)

Wang, Fang; Yuan, Feng-ying; Wang, Jin-zhi; Feng, Tang-fu; Hu, Guo-qi

2014-01-01

Highlights: • Two phase transitions in a narrow temperature range were observed and studied. • Both typical and inverse magnetocaloric effect were observed and discussed. • The inverse magnetocaloric effect was attributed to the spin-glass behavior. - Abstract: Magnetic properties and magnetocaloric effect (MCE) in Pr 2 CuSi 3 and Gd 2 CuSi 3 compounds were investigated systematically. Both Pr 2 CuSi 3 and Gd 2 CuSi 3 compounds experienced two phase transitions in a relatively narrow temperature range: first a paramagnet (PM)–ferromagnet (FM) second-order phase transition at 12 and 26 K and then a FM–spin glass (SG) transition at 6 K and 7.5 K, respectively. The magnetic entropy change (ΔS M ) was calculated based on Maxwell relation using the collected magnetization data. The maximum of ΔS M for Pr 2 CuSi 3 and Gd 2 CuSi 3 compounds was 7.6 and 5 J kg −1 K −1 , respectively, at the applied filed change of 0–5 T. The shape of the temperature dependence of ΔS M (ΔS M –T) curve was obviously different from that of the conventional magnetic materials undergoing only one typical phase transition. In the left half part of ΔS M –T curve, ΔS M is not very sensitive to the applied field and they tend to intersect with the decrease of temperature. Both typical conventional and inverse MCE behavior were observed in Gd 2 CuSi 3 , which would be originated from the two transition features at the low temperatures

The tin-rich copper lithium stannides: Li{sub 3}Cu{sub 6}Sn{sub 4} and Li{sub 2}CuSn{sub 2}

Energy Technology Data Exchange (ETDEWEB)

Fuertauer, Siegfried; Flandorfer, Hans [Vienna Univ. (Austria). Inst. of Inorganic Chemistry (Materials Chemisrty); Effenberger, Herta S. [Vienna Univ. (Austria). Inst. of Mineralogy and Crystallography

2015-05-01

The Sn rich ternary intermetallic compounds Li{sub 3}Cu{sub 6}Sn{sub 4} (CSD-427097) and Li{sub 2}CuSn{sub 2} (CSD-427098) were synthesized from the pure elements by induction melting and annealing at 400 C. Structural investigations were performed by powder- and single-crystal XRD. Li{sub 3}Cu{sub 6}Sn{sub 4} crystallizes in space group P6/mmm; it is structurally related to but not isotypic with MgFe{sub 6}Ge{sub 6} (a = 5.095(2) Aa, c = 9.524(3) Aa; wR{sub 2} = 0.059; 239 unique F{sup 2}-values, 17 free variables). Li{sub 3}Cu{sub 6}Sn{sub 4} is characterized by two sites with a mixed Cu:Sn occupation. In contrast to all other Cu-Li-Sn compounds known so far, any mixed occupation was found for Cu-Li pairs only. In addition, one Li site is only half occupied. The second Sn rich phase is Li{sub 2}CuSn{sub 2} (space group I4{sub 1}/amd, a = 4.4281(15) Aa, c = 19.416(4) Aa; wR{sub 2} = 0.033; 213 unique F{sup 2}-values, 12 atom free variables); it is the only phase in the Cu-Li-Sn system which is noted for full ordering. Both crystal structures exhibit 3D-networks which host Li atoms in channels. They are important for understanding the lithiation mechanism in Cu-Sn electrodes for Li-ion batteries.

Electrodeposition and Thermoelectric Properties of Cu-Se Binary Compound Films

Science.gov (United States)

Yang, Mengqian; Shen, Zhengwu; Liu, Xiaoqing; Wang, Wei

2016-03-01

Cu-Se binary compound films have been prepared by electrodeposition from solutions containing CuSO4, H2SeO3, and H2SO4 and their composition, structure, and thermoelectric performance analyzed. Moving the depositing potential negatively increased the Cu content in the film, remarkably so for relatively low Cu2+ concentration in the solution. X-ray diffraction analysis showed that the phase composition of the films varied with their Cu content. Cu-Se binary compound films electrodeposited from solutions with different concentration ratios of CuSO4 to H2SeO3 showed two different phases: α-Cu2- x Se (monoclinic) with Se content in the range of 33.3 at.% to 33.8 at.%, and β-Cu2Se (cubic) with Se content in the range of 35.3 at.% to 36.0 at.%. The highest power factor for electrodeposited Cu2- x Se film was 0.13 mW/(K2 m) with Seebeck coefficient of 56.0 μV/K.

Two different one-dimensional structural motifs in [catena-{Cu(tacn)}2Pd(CN)4]Br2.[catena-Cu(tacn)Pd(CN)4]2.H2O (tacn is 1,4,7-triazacyclononane).

Science.gov (United States)

Kuchár, Juraj; Cernák, Juraj

2009-07-01

The title compound, catena-poly[[bis[(triazacyclononane-kappa(3)N,N',N'')copper(II)]-di-mu-cyanido-kappa(4)N:C-palladate(II)-di-mu-cyanido-kappa(4)C:N] dibromide bis[[(triazacyclononane-kappa(3)N,N',N'')copper(II)]-mu-cyanido-kappa(2)N:C-[dicyanidopalladate(II)]-mu-cyanido-kappa(2)C:N] monohydrate], {[Cu(2)Pd(CN)(4)(C(6)H(15)N(3))(2)]Br(2).[Cu(2)Pd(2)(CN)(8)(C(6)H(15)N(3))(2)].H(2)O}(n), (I), was isolated from an aqueous solution containing tacn.3HBr (tacn is 1,4,7-triazacyclononane), Cu(2+) and tetracyanidopalladate(2-) anions. The crystal structure of (I) is essentially ionic and built up of 2,2-electroneutral chains, viz. [Cu(tacn)(NC)-Pd(CN)(2)-(CN)-], positively charged 2,4-ribbons exhibiting the composition {[Cu(tacn)(NC)(2)-Pd(CN)(2)-Cu(tacn)](2n+)}(n), bromide anions and one disordered water molecule of crystallization. The O atom of the water molecule occupies two unique crystallographic positions, one on a centre of symmetry, which is half occupied, and the other in a general position with one-quarter occupancy. One of the tacn ligands also exhibits disorder. The formation of two different types of one-dimensional structural motif within the same structure is a unique feature of this compound.

Genome-wide analysis of Tol2 transposon reintegration in zebrafish

Directory of Open Access Journals (Sweden)

Parinov Sergey

2009-09-01

Full Text Available Abstract Background Tol2, a member of the hAT family of transposons, has become a useful tool for genetic manipulation of model animals, but information about its interactions with vertebrate genomes is still limited. Furthermore, published reports on Tol2 have mainly been based on random integration of the transposon system after co-injection of a plasmid DNA harboring the transposon and a transposase mRNA. It is important to understand how Tol2 would behave upon activation after integration into the genome. Results We performed a large-scale enhancer trap (ET screen and generated 338 insertions of the Tol2 transposon-based ET cassette into the zebrafish genome. These insertions were generated by remobilizing the transposon from two different donor sites in two transgenic lines. We found that 39% of Tol2 insertions occurred in transcription units, mostly into introns. Analysis of the transposon target sites revealed no strict specificity at the DNA sequence level. However, Tol2 was prone to target AT-rich regions with weak palindromic consensus sequences centered at the insertion site. Conclusion Our systematic analysis of sequential remobilizations of the Tol2 transposon from two independent sites within a vertebrate genome has revealed properties such as a tendency to integrate into transcription units and into AT-rich palindrome-like sequences. This information will influence the development of various applications involving DNA transposons and Tol2 in particular.

The influence of pressure on the birefringence in semiconductor compounds ZnS, CuGaS2, and InPS4

International Nuclear Information System (INIS)

Lavrentyev, A.A.; Gabrelian, B.V.; Kulagin, B.B.; Nikiforov, I.Ya.; Sobolev, V.V.

2007-01-01

Using the modified method of augmented plane waves and the code WIEN2k the calculations of the electron band structure, densities of electron states, and imaginary part of dielectric response function were carried out for different polarization of the vector of electrical field ε xx and ε zz for the semiconductor compounds ZnS, CuGaS 2 , and InPS 4 . The calculations were performed both for undisturbed crystals and for distorted crystals due to the applied pressure. The compounds studied have the similar crystallographic structures: ZnS - sphalerite, CuGaS 2 - chalcopyrite, and InPS 4 - twice defective chalcopyrite. It is known, that in cubic ZnS there is no birefringence, whereas in CuGaS 2 and InPS 4 there is one. But CuGaS 2 has so called isotropic point (where ε xx =ε zz ) in the visible optical range, and InPS 4 has no such point. Our calculations of ε xx and ε zz have shown that in ZnS under the pressure the isotropic points arise, but in InPS 4 they do not exist. (copyright 2007 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

Spatiotemporal dynamics of the spin transition in [Fe (HB(tz)3) 2] single crystals

Science.gov (United States)

Ridier, Karl; Rat, Sylvain; Shepherd, Helena J.; Salmon, Lionel; Nicolazzi, William; Molnár, Gábor; Bousseksou, Azzedine

2017-10-01

The spatiotemporal dynamics of the spin transition have been thoroughly investigated in single crystals of the mononuclear spin-crossover (SCO) complex [Fe (HB (tz )3)2] (tz = 1 ,2 ,4-triazol-1-yl) by optical microscopy. This compound exhibits an abrupt spin transition centered at 334 K with a narrow thermal hysteresis loop of ˜1 K (first-order transition). Most single crystals of this compound reveal exceptional resilience upon repeated switching (several hundred cycles), which allowed repeatable and quantitative measurements of the spatiotemporal dynamics of the nucleation and growth processes to be carried out. These experiments revealed remarkable properties of the thermally induced spin transition: high stability of the thermal hysteresis loop, unprecedented large velocities of the macroscopic low-spin/high-spin phase boundaries up to 500 µm/s, and no visible dependency on the temperature scan rate. We have also studied the dynamics of the low-spin → high-spin transition induced by a local photothermal excitation generated by a spatially localized (Ø = 2 μ m ) continuous laser beam. Interesting phenomena have been evidenced both in quasistatic and dynamic conditions (e.g., threshold effects and long incubation periods, thermal activation of the phase boundary propagation, stabilization of the crystal in a stationary biphasic state, and thermal cutoff frequency). These measurements demonstrated the importance of thermal effects in the transition dynamics, and they enabled an accurate determination of the thermal properties of the SCO compound in the framework of a simple theoretical model.

Reactions of R(2)P-P(SiMe(3))Li with [(R'(3)P)(2)PtCl(2)]. A general and efficient entry to phosphanylphosphinidene complexes of platinum. Syntheses and structures of [(eta(2)-P=(i)Pr(2))Pt(p-Tol(3)P)(2)], [(eta(2)-P=(t)Bu(2))Pt(p-Tol(3)P)(2)], [{eta(2)-P=(N(i)Pr(2))(2)}Pt(p-Tol(3)P)(2)] and [{(Et(2)PhP)(2)Pt}(2)P(2)].

Science.gov (United States)

Domańska-Babul, Wioleta; Chojnacki, Jaroslaw; Matern, Eberhard; Pikies, Jerzy

2009-01-07

The reactions of lithium derivatives of diphosphanes R(2)P-P(SiMe(3))Li (R = (t)Bu, (i)Pr, Et(2)N and (i)Pr(2)N) with [(R'(3)P)(2)PtCl(2)] (R'(3)P = Et(3)P, Et(2)PhP, EtPh(2)P and p-Tol(3)P) proceed in a facile manner to afford side-on bonded phosphanylphosphinidene complexes of platinum [(eta(2)-P=R(2))Pt(PR'(3))(2)]. The related reactions of Ph(2)P-P(SiMe(3))Li with [(R'(3)P)(2)PtCl(2)] did not yield [(eta(2)-P=PPh(2))Pt(PR'(3))(2)] and resulted mainly in the formation of [{(R'(3)P)(2)Pt}(2)P(2)], Ph(2)P-PLi-PPh(2), (Me(3)Si)(2)PLi and (Me(3)Si)(3)P. Crystallographic data are reported for the compounds [(eta(2)-P=R(2))Pt(p-Tol(3)P)(2)] (R = (t)Bu, (i)Pr, ((i)Pr(2)N)(2)P) and for [{(Et(2)PhP)(2)Pt}(2)P(2)].

Group IB Organometallic Chemistry XIX.Synthesis and characterization of mixed-organocopper cluster compounds R4R'2Cu6 containing aryl and acetylide ligands.

NARCIS (Netherlands)

Koten, G. van; Hoedt, R.W.M. ten; Noltes, J.G.

1977-01-01

Mixed-organocopper cluster compounds Ar4Cu6(CCR)2 (Ar = 2-Me2NC6H4, R = phenyl, 4-tolyl, 2,4-xylyl or mesityl) have been prepared in high yield by the ligand-substitution reaction of Ar4Cu6Br2 with two equivalents of LiCCR. Ar4Cu6(CCC6H4CH3-4)2 has also been prepared via the aryl¡ªarylacetylide

Raman spectra of Cu{sub 2}B{sup II}C{sup IV}X{sub 4}{sup VI} magnetic quaternary semiconductor compounds with tetragonal stannite type structure

Energy Technology Data Exchange (ETDEWEB)

Rincón, C., E-mail: crincon@ula.ve; Quintero, M.; Power, Ch.; Moreno, E.; Quintero, E.; Morocoima, M. [Centro de Estudios de Semiconductores, Departamento de Física, Facultad de Ciencias, Universidad de Los Andes, Mérida (Venezuela, Bolivarian Republic of); Henao, J. A.; Macías, M. A. [Grupo de Investigación en Química Estructural, Facultad de Ciencias, Escuela de Química, Universidad Industrial de Santander, Apartado Aéreo 678, Bucaramanga (Colombia)

2015-05-28

A comparative study of the Raman spectra of Cu{sub 2}B{sup II}C{sup IV}S{sub 4}{sup VI} and Cu{sub 2}B{sup II}C{sup IV}Se{sub 4}{sup VI}(where B = Mn or Fe) magnetic quaternary semiconductor compounds with stannite-type structure (I4{sup ¯}2m) has been done. Most of the fourteen Raman lines expected for these materials were observed in the spectra. The two strongest lines observed have been assigned to the IR inactive A{sub 1}{sup 1} and A{sub 1}{sup 2} stannite modes that originated from the motion of the S or Se anion around the Cu and C{sup IV} cations remaining at rest. The shift in the frequency of these two lines of about 150 cm{sup −1} to lower energies observed in Cu{sub 2}B{sup II}C{sup IV}Se{sub 4}{sup VI} compounds as compared to those in Cu{sub 2}B{sup II}C{sup IV}S{sub 4}{sup VI} ones, can then be explained as due to the anion mass effect. Based on the fact that values of these frequencies depend mainly on anion mass and bond-stretching forces between nearest-neighbor atoms, the vibrational frequencies v{sup ¯}(A{sub 1}{sup 2}) and v{sup ¯}(A{sub 1}{sup 2}) of both modes for several Cu{sub 2}B{sup II}C{sup IV}X{sub 4}{sup VI} stannite compounds (where X = S, Se, or Te) very close to the experimental data reported for these materials were calculated from a simple model that relates these stretching forces to the anion-cation bond-distances.

Displacement waves in La2CuO(4-delta) and La(1.85)Sr(0.15)CuO(4-delta)

Science.gov (United States)

Kajitani, Tsuyoshi; Onozuka, Takashi; Yamaguchi, Yasuo; Hirabayashi, Makoto; Syono, Yasuhiko

1987-11-01

Structural investigation of orthorhombic La2CuO(4-delta) and La(1.85)Sr(0.15)CuO(4-delta) was carried out by means of X-ray and neutron diffraction on the basis of the space group Cmmm. The periodic expansion/contraction type distortion of CuO6 octahedra was found in both orthorhombic compounds. The distortion is nearly one-dimensional in La2CuO(4-delta) but is two-dimensional in La(1.85)Sr(0.15)CuO(4-delta). The existence of a charge-density wave is highly possible in the structures.

Specific features of band structure and optical anisotropy of Cu{sub 2}CdGeSe{sub 4} quaternary compounds

Energy Technology Data Exchange (ETDEWEB)

Brik, M.G., E-mail: brik@fi.tartu.ee [College of Mathematics and Physics, Chongqing University of Posts and Telecommunications, Chongqing 400065 (China); Institute of Physics, University of Tartu, Riia 142, Tartu 51014 (Estonia); Institute of Physics, Jan Dlugosz University, Armii Krajowej 13/15, PL-42200 Czestochowa (Poland); Parasyuk, O.V. [Department of Chemistry, Eastern European National University, Voli 13, Lutsk 43025 (Ukraine); Myronchuk, G.L. [Department of Physics, Eastern European National University, Voli 13, Lutsk 43025 (Ukraine); Kityk, I.V. [Institute of Materials Science and Engineering, Technical University of Czestochowa, Al. Armii Krajowej 19, 42-200 Czestochowa (Poland)

2014-09-15

Complex theoretical and experimental studies of the band structure and optical functions of a new Cu{sub 2}CdGeSe{sub 4} quaternary crystal are reported. The benchmark band structure calculations were performed using the first-principles methods. As a result, the structural, electronic, optical and elastic properties of Cu{sub 2}CdGeSe{sub 4} were calculated in the general gradient approximation (GGA) and local density approximation (LDA). The calculated dielectric function and optical absorption spectra exhibit some anisotropic behavior. Detailed analysis of the band energy dispersion and effective space charge density helped in establishing the origin of the band structure anisotropy. All calculated properties are compared with the experimental data. An additional comparison with a similar crystal of Cu{sub 2}CdGeSe{sub 4} allowed to reveal the role played by the anions (S or Se) in formation of the optical properties of these two materials. - Highlights: • The structural, electronic, optical properties of Cu{sub 2}CdGeSe{sub 4} were calculated. • Pressure effects on these properties were modeled. • Comparison with a similar compound of Cu{sub 2}CdGeS{sub 4} was performed.

Preparation and characterization of a layered perovskite-type organic-inorganic hybrid compound (C8NH6-CH2CH2NH3)2CuCl4

International Nuclear Information System (INIS)

Zheng Yingying; Wu Gang; Deng Meng; Chen Hongzheng; Wang Mang; Tang, B.-Z.

2006-01-01

The organic-inorganic hybrid compound (C 8 NH 6 -CH 2 CH 2 NH 3 ) 2 CuCl 4 (AEI-CuCl 4 ) was synthesized from ethanol solution containing copper chloride and 3-2-(aminoethyl) indole hydrochloride (AEI-HCl). High order diffraction peaks corresponding to (0 0 l; l = 2, 4, 6, ...) observed in the X-ray diffraction profile of AEI-CuCl 4 indicated the formation of hybrid crystal with layered perovskite structure. The organic-inorganic hybrid crystal thin film can be easily prepared by spin-coating method from the ethanol solution of the AEI-CuCl 4 perovskite and it showed characteristic absorptions of CuCl-based layered perovskite centered at 288 and 388 nm, as well as the photoluminescence peak at around 420 nm. The unaided-eye-detectable blue fluorescence emission comes from the cooperation of AEI-HCl and AEI-CuCl 4 perovskite, in which protonized aminoethyl indole dominates the shape of the spectrum and the enhancement of emission intensity is due to the formation of the perovskite structure. The thermal analysis presented that the AEI-CuCl 4 perovskite started to melt at 182 deg. C, together with the beginning of the decomposition of the hybrids. Compared with the organic-inorganic perovskite hybrids reported previously, the AEI-CuCl 4 perovskite shows a novel stepwise decomposition behavior

Displacement waves in La/sub 2/CuO(4-delta) and La(1. 85)Sr(0. 15)CuO(4-delta)

Energy Technology Data Exchange (ETDEWEB)

Kajitani, T.; Onozuka, T.; Yamaguchi, Y.; Hirabayashi, M.; Syono, Y.

1987-11-01

Structural investigation of orthorhombic La/sub 2/CuO(4-delta) and La(1.85)Sr(0.15)CuO(4-delta) was carried out by means of X-ray and neutron diffraction on the basis of the space group Cmmm. The periodic expansion/contraction type distortion of CuO6 octahedra was found in both orthorhombic compounds. The distortion is nearly one-dimensional in La/sub 2/CuO(4-delta) but is two-dimensional in La(1.85)Sr(0.15)CuO(4-delta). The existence of a charge-density wave is highly possible in the structures. 20 references.

Low-dimensional compounds containing cyano groups. XIV. Crystal structure, spectroscopic, thermal and magnetic properties of [CuL 2][Pt(China)4] complexes (L=ethylenediamine or N,N-dimethylethylenediamine)

International Nuclear Information System (INIS)

Potocnak, Ivan; Vavra, Martin; Cizmar, Erik; Tibenska, Katarina; Orendacova, Alzbeta; Steinborn, Dirk; Wagner, Christoph; Dusek, Michal; Fejfarova, Karla; Schmidt, Harry; Muller, Thomas; Orendac, Martin; Feher, Alexander

2006-01-01

Violet crystals of [Cu(en) 2 ][Pt(China) 4 ] and blue crystals of [Cu(dmen) 2 ][Pt(China) 4 ] were crystallized from the water-methanol solution containing CuCl 2 .2H 2 O, ethylenediamine (en) or N,N-dimethylethylenediamine (dmen) and K 2 [Pt(China) 4 ].3H 2 O. Both compounds were characterized using elemental analysis, infrared and UV-VIS spectroscopy, magnetic measurements, specific heat measurements and thermal analysis. X-ray structure analysis revealed chain-like structure in both compounds. The covalent chains are built of Cu(II) ions linked by [Pt(China) 4 ] 2- anions in the [111] and [101] direction, respectively. The Cu(II) atoms are hexacoordinated by four nitrogen atoms in the equatorial plane from two molecules of bidentate ligands L with average Cu-N distance of 2.022(2) and 2.049(4) A, respectively. Axial positions are occupied by two nitrogen atoms from bridging [Pt(China) 4 ] 2- anions at longer Cu-N distance of 2.537(2) and 2.600(5) A, respectively. Both materials are characterized by the presence of weak antiferromagnetic exchange coupling. Despite the one-dimensional (1D) character of the structure, the analysis of magnetic properties and specific heat at very low temperatures shows that [Cu(en) 2 ][Pt(China) 4 ] behaves as two-dimensional (2D) spatially anisotropic square lattice Heisenberg magnet, while more pronounced influence of interlayer coupling is observed in [Cu(dmen) 2 ][Pt(China) 4 ]. - Graphical abstract: Chain-like structure in [Cu(en) 2 ][Pt(China) 4 ] (R=H) and [Cu(dmen) 2 ][Pt(China) 4 ] (R=CH 3 ) compounds

Mineralization of volatile organic compounds (VOCs) over the catalyst CuO-Co3O4-CeO2 and its applications in industrial odor control

KAUST Repository

Somekawa, Shouichi; Hagiwara, Toshiya; Fujii, Kyoko; Kojima, Masayuki; Shinoda, Tsutomu; Takanabe, Kazuhiro; Domen, Kazunari

2011-01-01

Volatile organic compounds (VOCs) present at ppm levels were decomposed over the catalyst CuO-Co3O4-CeO2 (Cu:Co:Ce = 10:45:45 in mol) in an attempt to scale up for industrial odor control. In addition to enhancing the catalytic activity, CuO-Co3O4 and CeO2 helped, respectively, to maintain the strength of the pelleted catalysts and inhibit their sintering. Using toluene as a VOC model compound, kinetic analysis of the total oxidation to carbon dioxide was conducted. The odor emitted from paint-drying processes could be eliminated effectively using CuO-Co3O4-CeO2 (Cu:Co:Ce = 10:45:45) pelleted catalysts (188 ml) in a large-scale system. © 2011 Elsevier B.V. All rights reserved.

Mineralization of volatile organic compounds (VOCs) over the catalyst CuO-Co3O4-CeO2 and its applications in industrial odor control

KAUST Repository

Somekawa, Shouichi

2011-12-01

Volatile organic compounds (VOCs) present at ppm levels were decomposed over the catalyst CuO-Co3O4-CeO2 (Cu:Co:Ce = 10:45:45 in mol) in an attempt to scale up for industrial odor control. In addition to enhancing the catalytic activity, CuO-Co3O4 and CeO2 helped, respectively, to maintain the strength of the pelleted catalysts and inhibit their sintering. Using toluene as a VOC model compound, kinetic analysis of the total oxidation to carbon dioxide was conducted. The odor emitted from paint-drying processes could be eliminated effectively using CuO-Co3O4-CeO2 (Cu:Co:Ce = 10:45:45) pelleted catalysts (188 ml) in a large-scale system. © 2011 Elsevier B.V. All rights reserved.

Characterization of quasi-one-dimensional S=1/2 Heisenberg antiferromagnets Sr2Cu(PO4)2 and Ba2Cu(PO4)2 with magnetic susceptibility, specific heat, and thermal analysis

International Nuclear Information System (INIS)

Belik, A.A.; Azuma, M.; Takano, M.

2004-01-01

Properties of Sr 2 Cu(PO 4 ) 2 and Ba 2 Cu(PO 4 ) 2 having [Cu(PO 4 ) 2 ] ∞ linear chains in their structures with Cu-O-P-O-Cu linkages were studied by magnetic susceptibility (T=2-400 K, H=100 Oe) and specific heat measurements (T=0.45-21 K). Magnetic susceptibility versus temperature curves, χ(T), showed broad maxima at T M =92 K for Sr 2 Cu(PO 4 ) 2 and T M =82 K for Ba 2 Cu(PO 4 ) 2 characteristic of quasi-one-dimensional systems. The χ(T) data were excellently fitted by the spin susceptibility curve for the uniform S=1/2 chain (plus temperature-independent and Curie-Weiss terms) with g=2.153(4) and J/k B =143.6(2) K for Sr 2 Cu(PO 4 ) 2 and g=2.073(4) and J/k B =132.16(9) K for Ba 2 Cu(PO 4 ) 2 (Hamiltonian H=JΣS i S i+1 ). The similar J/k B values were obtained from the specific heat data. No anomaly was observed on the specific heat from 0.45 to 21 K for both compounds indicating that the temperatures of long-range magnetic ordering, T N , were below 0.45 K. Sr 2 Cu(PO 4 ) 2 and Ba 2 Cu(PO 4 ) 2 are an excellent physical realization of the S=1/2 linear chain Heisenberg antiferromagnet with k B T N /J 2 CuO 3 (k B T N /J∼0.25%) and γ-LiV 2 O 5 (k B T N /J 2 Cu(PO 4 ) 2 and Ba 2 Cu(PO 4 ) 2 were stable in air up to 1280 and 1150 K, respectively

Copper(II) perrhenate Cu(C{sub 3}H{sub 7}OH){sub 2}(ReO{sub 4}){sub 2}: Synthesis from isopropanol and CuReO{sub 4}, structure and properties

Energy Technology Data Exchange (ETDEWEB)

Mikhailova, D., E-mail: d.mikhailova@ifw-dresden.de [Karlsruhe Institute of Technology (KIT), Institute for Applied Materials (IAM), Hermann-von-Helmholtz-Platz 1, D-76434 Eggenstein-Leopoldshafen (Germany); Institute for Complex Materials, IFW Dresden, Helmholtzstrasse 20, D-01069 Dresden (Germany); Max Planck Institute for Chemical Physics of Solids, Nöthnitzer Str. 40, D-01187 Dresden (Germany); Engel, J.M. [Materials Science, Technische Universität Darmstadt, Alarich-Weiss-Str. 2, D-64287 Darmstadt (Germany); Schmidt, M. [Max Planck Institute for Chemical Physics of Solids, Nöthnitzer Str. 40, D-01187 Dresden (Germany); Tsirlin, A.A. [National Institute of Chemical Physics and Biophysics, Akadeemia tee 23, 12618 Tallinn (Estonia); Ehrenberg, H. [Karlsruhe Institute of Technology (KIT), Institute for Applied Materials (IAM), Hermann-von-Helmholtz-Platz 1, D-76434 Eggenstein-Leopoldshafen (Germany); Materials Science, Technische Universität Darmstadt, Alarich-Weiss-Str. 2, D-64287 Darmstadt (Germany)

2015-12-15

The crystal structure of Cu{sup +}Re{sup 7+}O{sub 4} is capable of a quasi-reversible incorporation of C{sub 3}H{sub 7}OH molecules. A room-temperature reaction between CuReO{sub 4} and C{sub 3}H{sub 7}OH under oxidizing conditions leads to the formation of a novel metal-organic hybrid compound Cu{sup 2+}(C{sub 3}H{sub 7}OH){sub 2}(ReO{sub 4}){sub 2}. Upon heating under reducing conditions, this compound transforms back into CuReO{sub 4}, albeit with ReO{sub 2} and metallic Cu as by-products. The crystal structure of Cu(C{sub 3}H{sub 7}OH){sub 2}(ReO{sub 4}){sub 2} solved from single-crystal X-ray diffraction (Pbca, a=10.005(3) Å, b=7.833(2) Å, and c=19.180(5) Å) reveals layers of corner-sharing CuO{sub 6}-octahedra and ReO{sub 4}-tetrahedra, whereas isopropyl groups are attached to both sides of these layers, thus providing additional connections within the layers through hydrogen bonds. Cu(C{sub 3}H{sub 7}OH){sub 2}(ReO{sub 4}){sub 2} is paramagnetic down to 4 K because the spatial arrangement of the Cu{sup 2+} half-filled orbitals prevents magnetic superexchange. The paramagnetic effective moment of 2.0(1) μ{sub B} is slightly above the spin-only value and typical for Cu{sup 2+} ions. - Highlights: • Novel Cu(C{sub 3}H{sub 7}OH){sub 2}(ReO{sub 4}){sub 2} compound has a sequence of inorganic and organic layers. • Hydrogen bonds provide an additional bonding Isopropanol molecules serve as a reducing agent during decomposition. • No direct Cu-O-Re-O-Cu connections via d{sub x2-y2} orbital of Cu{sup 2+} explain paramagnetism. • Hydrogen bonds provide an additional bonding. • Isopropanol molecules serve as a reducing agent during decomposition.

Structural characterization of two new quaternary chalcogenides: CuCo{sub 2}InTe{sub 4} and CuNi{sub 2}InTe{sub 4}

Energy Technology Data Exchange (ETDEWEB)

Delgado, Gerzon E.; Grima-Gallardo, Pedro; Nieves, Luis, E-mail: gerzon@ula.ve [Universidad de Los Andes, Merida (Venezuela, Bolivarian Republic of); Cabrera, Humberto [Centro Multidisciplinario de Ciencias, Instituto Venezolano de Investigaciones Cientificas (IVIC), Merida (Venezuela, Bolivarian Republic of); Glenn, Jennifer R.; Aitken, Jennifer A. [Department of Chemistry and Biochemistry, Duquesne University, Pittsburgh, PA (United States)

2016-11-15

The crystal structure of the chalcogenide compounds CuCo{sub 2}InTe{sub 4} and CuNi{sub 2}InTe{sub 4} , two new members of the I-II{sub 2}-III-VI{sub 4} family, were characterized by Rietveld refinement using X-ray powder diffraction data. Both materials crystallize in the tetragonal space group I4-bar 2m (No. 121), Z = 2, with a stannite-type structure, with the binaries CoTe and NiTe as secondary phases. (author)

Quadruple-layered perovskite (CuCl)Ca2NaNb4O13

International Nuclear Information System (INIS)

Kitada, A.; Tsujimoto, Y.; Yamamoto, T.; Kobayashi, Y.; Narumi, Y.; Kindo, K.; Aczel, A.A.; Luke, G.M.; Uemura, Y.J.; Kiuchi, Y.; Ueda, Y.; Yoshimura, K.; Ajiro, Y.; Kageyama, H.

2012-01-01

We will present the synthesis, structure and magnetic properties of a new quadruple-layered perovskite (CuCl)Ca 2 NaNb 4 O 13 . Through a topotactic ion-exchange reaction with CuCl 2 , the precursor RbCa 2 NaNb 4 O 13 presumably having an incoherent octahederal tliting changes into (CuCl)Ca 2 NaNb 4 O 13 with a 2a p ×2a p ×2c p superstructure (tetragonal; a=7.73232(5) Å, c=39.2156(4) Å). The well-defined superstructure for the ion-exchanged product should be stabilized by the inserted CuCl 4 O 2 octahedral layers that firmly connect with neighboring perovskite layers. Magnetic studies show the absence of long-range magnetic ordering down to 2 K despite strong in-plane interactions. Aleksandrov′s group theory and Rietveld refinement of synchrotron X-ray diffraction data suggest the structure to be of I4/mmm space group with in-phase tilting along the a and b axes, a two-tilt system (++0). - Graphical Abstract: We present a quadruple-layered copper oxyhalide (CuCl)Ca 2 NaNb 4 O 13 synthesized through a topotactic ion-exchange reaction of RbCa 2 NaNb 4 O 13 with CuCl 2 . The compound has a well-defined superstructure. Magnetic studies suggest the absence of magnetic order even at 2 K. Highlights: ► (CuCl)Ca 2 NaNb 4 O 13 was prepared by ion-exchange reaction of RbCa 2 NaNb 4 O 13 with CuCl 2 . ► Compound has a 2a p ×2a p ×2c p superstructure (tetragonal; a=7.73 Å, c=39.21 Å). ► Such a well-defined superstructure was not observed in the precursor compound. ► Aleksandrov′s theory and Rietveld study suggest a (++0) octahedral tilting (I4/mmm). ► Magnetic studies revealed the absence of magnetic order down to 2 K.

Synthesis of a new compound - Sr2CuO2CO3

International Nuclear Information System (INIS)

Fomichev, D.V.; Khardanov, A.L.; Antipov, E.V.; Kovba, L.M.

1990-01-01

A new compound of Sr 2 CuO 2 CO 3 composition, being an intermediate product of solid phase synthesis in air in SrCo 3 -CuO system at T 2 CuO 2 CO 3 have low resistance at room temperature and semiconductor type conductivity

NMR/NQR study of the superconductor Y2Ba4Cu7O15

International Nuclear Information System (INIS)

Stern, R.

1995-01-01

This dissertation concentrates on several important aspects of the high temperature superconductivity research. Nuclear magnetic resonance (NMR) and nuclear quadrupole resonance (NQR) studies in Y-Ba-O compounds contribute information regarding various aspects, ranging from the direct observation of strong coupling between the adjacent planes in the double plane to conclusions concerning the spatial symmetry of paring state in these cuprates. We report the first results in the 93 K superconductor Y 2 Ba 4 Cu 7 O 15 . This compound turns out to be a structure containing differently doped CuO 2 planes. The planes in the 1-2-3(1-2-4) block are only slightly lower (higher) doped than those in the corresponding parent compounds YBa 2 Cu 3 O 7 and YBa 2 Cu 4 O 8 . The results obtained from measurements on oxygen depleted Y 2 Ba 4 Cu 7 O 15-x show two new features which could explain the dissimilar variation of T c with oxygen content compared to YBa 2 Cu 3 O 7-x : i) the double chains donate charge carriers to the planes and ii) the chain fragments which survive when emptying single chains are longer than in YBa 2 Cu 3 O 7-x . The pressure induced charge transfer from chain to plane in each block of Y 2 Ba 4 Cu 7 O 15 is the same as in the corresponding parent compound. We explore the strong coupling between nonequivalent planes in this compound using the three main NMR/NQR quantities, K spin , 1/T 1 ; and T 2G,ind , and estimate its approximate strength directly from spin-echo double resonance (SEDOR) experiments. We obtain for the ratio of the effective inter- and intraplane exchange-coupling constants the value of 0.3 just above T c . This ratio decreases with increasing temperature. (author) figs., tabs., refs

Synthesis and characterization of YBaCu2O5-δ compound

Science.gov (United States)

Ehsandoust, A.; Sandoghchi, M.; Mokhtari, P.; Akhavan, M.

2018-05-01

YBaCu2O5 compound as one of the possible microstructures of Y3Ba5Cu8O19 has been synthesized. The X-ray diffraction analysis of this compound indicates that its formation is accompanied with the formation of YBa2Cu3O7-δ. The observed superconductivity around ∼92 K supports this. So, it seems that YBa2Cu3O7-δ is responsible for the observed superconductivity in YBaCu2O5, and this phase is not an independent superconducting phase. Consequently, the overall effect of the YBaCu2O5 formation during the Y3Ba5Cu8O19 fabrication process could be a reduction in Tc.

Low-dimensional compounds containing cyano groups. XVII. Crystal structure, spectroscopic, thermal and magnetic properties of [Cu(bmen)2][Pt(CN)4] (bmen=N,N'-dimethylethylenediamine)

International Nuclear Information System (INIS)

Potocnak, Ivan; Vavra, Martin; Cizmar, Erik; Kajnakova, Marcela; Radvakova, Alena; Steinborn, Dirk; Zvyagin, Sergei A.; Wosnitza, Jochen; Feher, Alexander

2009-01-01

The synthesis, structural analysis, spectroscopic studies, susceptibility and specific-heat measurements of {[Cu(bmen) 2 ][Pt(CN) 4 ]} n (bmen=N,N'-dimethylethylenediamine) are presented. X-ray crystal-structure analysis revealed that the [Pt(CN) 4 ] 2- building blocks are combined with [Cu(bmen) 2 ] 2+ units to form a chain-like structure along the a axis. The Cu(II) atoms are hexacoordinated by four nitrogen atoms in the equatorial plane belonging to two molecules of bidentate bmen ligands with average Cu-N distance of 2.043(18) A. The axial positions are occupied by two nitrogen atoms from bridging [Pt(CN) 4 ] 2- anions at a longer axial Cu-N distance of 2.490(4) A. The compound is characterized by the presence of a weak antiferromagnetic exchange coupling J/k B =0.6 K. Despite the one-dimensional (1D) character of the structure, the analysis of the magnetic properties and specific heat at very low temperatures shows that [Cu(bmen) 2 ][Pt(CN) 4 ] behaves as a two-dimensional (2D) square-lattice Heisenberg magnet with weak interlayer coupling. - Graphical abstract: The synthesis, structural analysis, spectroscopic studies, susceptibility and specific-heat measurements of {[Cu(bmen) 2 ][Pt(CN) 4 ]} n (bmen=N,N'-dimethylethylenediamine) are presented. X-ray crystal-structure analysis revealed that the [Pt(CN) 4 ] 2- building blocks are combined with [Cu(bmen) 2 ] 2+ units to form a chain-like structure. The compound is characterized by the presence of a weak antiferromagnetic exchange coupling J/k B =-0.6 K. Despite the one-dimensional character of the structure, the analysis of the magnetic properties and specific heat at very low temperatures shows that [Cu(bmen) 2 ][Pt(CN) 4 ] behaves as a two-dimensional square-lattice Heisenberg magnet with weak interlayer coupling

Phase relations in the quasi-binary Cu{sub 2}GeS{sub 3}-ZnS and quasi-ternary Cu{sub 2}S-Zn(Cd)S-GeS{sub 2} systems and crystal structure of Cu{sub 2}ZnGeS{sub 4}

Energy Technology Data Exchange (ETDEWEB)

Parasyuk, O.V. [Department of General and Inorganic Chemistry, Volyn State University, Voli Ave 13, 43009 Lutsk (Ukraine)]. E-mail: oleg@lab.univer.lutsk.ua; Piskach, L.V. [Department of General and Inorganic Chemistry, Volyn State University, Voli Ave 13, 43009 Lutsk (Ukraine); Romanyuk, Y.E. [Advanced Photonics Laboratory, Institute of Imaging and Applied Optics, Ecole Polytechnique Federale de Lausanne, CH-1015 Lausanne (Switzerland); Olekseyuk, I.D. [Department of General and Inorganic Chemistry, Volyn State University, Voli Ave 13, 43009 Lutsk (Ukraine); Zaremba, V.I. [Department of Inorganic Chemistry, Ivan Franko National University of Lviv, 6 Kyryla and Mefodiya Str., 79005 L' viv (Ukraine); Pekhnyo, V.I. [V.I. Vernadskii Institute of General and Inorganic Chemistry, Ukrainian National Academy of Sciences, Palladina Ave 32-34, 03680 Kiev (Ukraine)

2005-07-19

The isothermal section of the Cu{sub 2}S-Zn(Cd)S-GeS{sub 2} systems at 670K was constructed using X-ray diffraction analysis. At this temperature, two quaternary intermediate phases, Cu{sub 2}CdGeS{sub 4} and {approx}Cu{sub 8}CdGeS{sub 7}, exist in the Cu{sub 2}S-CdS-GeS{sub 2} system, and only one phase, Cu{sub 2}ZnGeS{sub 4}, exists in the Cu{sub 2}S-ZnS-GeS{sub 2} system. The phase diagram of the Cu{sub 2}GeS{sub 3}-ZnS system was constructed using differential-thermal analysis and X-ray diffraction, and the existence of Cu{sub 2}ZnGeS{sub 4} has been confirmed. It forms incongruently at 1359K. Powder X-ray diffraction was used to refine the crystal structure of Cu{sub 2}ZnGeS{sub 4}, which crystallizes in the tetragonal stannite-type structure at 670K (space group I4-bar 2m, a=0.534127(9)nm, c=1.05090(2)nm, R{sub I}=0.0477). The possibility of the formation of quaternary compounds in the quasi-ternary systems A{sup I}{sub 2}X-B{sup II}X-C{sup IV}X{sub 2}, where A{sup I}-Cu, Ag; B{sup II}-Zn, Cd, Hg; C{sup IV}-Si, Ge, Sn and X-S, Se, Te is discussed.

A hardware-oriented concurrent TZ search algorithm for High-Efficiency Video Coding

Science.gov (United States)

Doan, Nghia; Kim, Tae Sung; Rhee, Chae Eun; Lee, Hyuk-Jae

2017-12-01

High-Efficiency Video Coding (HEVC) is the latest video coding standard, in which the compression performance is double that of its predecessor, the H.264/AVC standard, while the video quality remains unchanged. In HEVC, the test zone (TZ) search algorithm is widely used for integer motion estimation because it effectively searches the good-quality motion vector with a relatively small amount of computation. However, the complex computation structure of the TZ search algorithm makes it difficult to implement it in the hardware. This paper proposes a new integer motion estimation algorithm which is designed for hardware execution by modifying the conventional TZ search to allow parallel motion estimations of all prediction unit (PU) partitions. The algorithm consists of the three phases of zonal, raster, and refinement searches. At the beginning of each phase, the algorithm obtains the search points required by the original TZ search for all PU partitions in a coding unit (CU). Then, all redundant search points are removed prior to the estimation of the motion costs, and the best search points are then selected for all PUs. Compared to the conventional TZ search algorithm, experimental results show that the proposed algorithm significantly decreases the Bjøntegaard Delta bitrate (BD-BR) by 0.84%, and it also reduces the computational complexity by 54.54%.

Magnetic Excitations in Cu2Fe2Ge4O13

International Nuclear Information System (INIS)

Masuda, Takatsugu; Zheludev, Andrey I.; Sales, Brian C.; Imai, S.; Uchinokura, K.

2005-01-01

Magnetic excitations in the cooperative ordered state in a weakly coupled Fe chains and Cu dimers compound Cu 2 Fe 2 Ge 4 O 13 is studied by thermal neutron scattering technique. We show that the low energy excitations up to 10 meV in wide q range are well described by spin wave theory of weakly coupled Fe chains. In higher energy range a narrow band excitation that can be associated with Cu dimers is observed at ℎω-24 meV. Both types of excitations can be understood by treating the weak coupling between Fe chains and Cu dimers at the level of Mean Field/Random Phase Approximation.

Structural and elemental characterization of high efficiency Cu2ZnSnS4 solar cells

Science.gov (United States)

Wang, Kejia; Shin, Byungha; Reuter, Kathleen B.; Todorov, Teodor; Mitzi, David B.; Guha, Supratik

2011-01-01

We have carried out detailed microstructural studies of phase separation and grain boundary composition in Cu2ZnSnS4 based solar cells. The absorber layer was fabricated by thermal evaporation followed by post high temperature annealing on hot plate. We show that inter-reactions between the bottom molybdenum and the Cu2ZnSnS4, besides triggering the formation of interfacial MoSx, results in the out-diffusion of Cu from the Cu2ZnSnS4 layer. Phase separation of Cu2ZnSnS4 into ZnS and a Cu-Sn-S compound is observed at the molybdenum-Cu2ZnSnS4 interface, perhaps as a result of the compositional out-diffusion. Additionally, grain boundaries within the thermally evaporated absorber layer are found to be either Cu-rich or at the expected bulk composition. Such interfacial compound formation and grain boundary chemistry likely contributes to the lower than expected open circuit voltages observed for the Cu2ZnSnS4 devices.

First-principles study of defect formation in a photovoltaic semiconductor Cu2ZnGeSe4

Science.gov (United States)

Nishihara, Hironori; Maeda, Tsuyoshi; Wada, Takahiro

2018-02-01

The formation energies of neutral Cu, Zn, Ge, and Se vacancies in kesterite-type Cu2ZnGeSe4 were evaluated by first-principles pseudopotential calculations using plane-wave basis functions. The calculations were performed at typical points in Cu-(Zn1/2Ge1/2)-Se and Cu3Se2-ZnSe-GeSe2 pseudoternary phase diagrams for Cu2ZnGeSe4. The results were compared with those for Cu2ZnSnSe4, Cu2ZnGeS4, and Cu2ZnSnS4 calculated using the same version of the CASTEP program code. The results indicate that Cu vacancies are easily formed in Cu2ZnGeSe4 under the Cu-poor condition as in the above compounds and CuInSe2, suggesting that Cu2ZnGeSe4 is also a preferable p-type absorber material for thin-film solar cells. The formation energies of possible antisite defects, such as CuZn and CuGe, and of possible complex defects, such as CuZn+ZnCu, were also calculated and compared within the above materials. The antisite defect of CuZn, which has the smallest formation energy within the possible defects, is concluded to be the most hardly formed in Cu2ZnGeSe4 among the compounds.

A new (4, 6)-connected Cu(I) coordination polymer based on rare tetranuclear [Cu4I2] clusters: Synthesis, crystal structure, luminescent and photocatalytic properties

Science.gov (United States)

Cui, Li-Jing; Liu, Chun-Yan; Bian, Ming; Yu, Li-Jun

2018-03-01

A new Cu(I) coordination polymer, namely [Cu5I3(L)2]n (1 HL = 3-(4-pyridyl)-5-(3-pyridyl)-1,2,4-triazolyl), was solvothermally synthesized using CuI, HL and NaI as the starting materials. Single crystal X-ray structural analysis shows that compound 1 features a (4, 6)-connected 3D framework employing rare tetranuclear [Cu4I2] clusters as building subunits. It exhibits intense metal-to-ligand luminescence and excellent photocatalytic activity on degradation of methylene blue (MB).

POX 4 and Tol 35: Two Peculiar Wolf-Rayet Dwarf Galaxies

Science.gov (United States)

Méndez, David I.; Esteban, César

1999-12-01

We present results of narrowband (Hα and adjacent continuum) and broadband (U, B, and V) optical CCD imaging together with high-resolution Hα spectroscopy of the blue compact Wolf-Rayet dwarf galaxies POX 4 and Tol 35. POX 4 has a fainter, irregular, and diffuse companion located 20.5" (4.7 kpc) along the minor axis of the galaxy, which is visible also in the Hα emission. The difference in recession velocity between the galaxy and the companion is about 130 km s-1. The observational results lead us to propose that POX 4 could be interpreted as a low-mass ring galaxy, produced by a head-on intrusion of the fainter companion. Regarding the other object, a spectrum taken along the major axis of Tol 35 shows the coexistence of systems of motion with a velocity difference of about 50 km s-1. Moreover, the deep continuum-subtracted Hα image of the galaxy shows very faint features that resemble the beginning of crossed tidal tails or gaseous filaments powered by the mechanical action of the young stellar population. In this sense, Tol 35 could be interpreted either as an object in an intermediate-stage merging process between two gas-rich dwarf galaxies or as an object suffering the effect of a galactic wind.

Subsolidus phase relations of Bi2O3-Nd2O3-CuO

International Nuclear Information System (INIS)

Sun Yezhou

1997-01-01

The subsolidus phase relations of the Bi 2 O 3 -Nd 2 O 3 -CuO ternary system and its binary systems along with crystallographic parameters of the compounds were investigated by X-ray powder diffraction and differential thermal analysis. The room temperature section of the phase diagram of the Bi 2 O 3 -Nd 2 O 3 -CuO system can be divided into two diphase regions and six triphase regions. No ternary compound was found. There exist two solid solutions (α, β) and a compound Bi 0.55 Nd 0.45 O 1.5 in the (Bi 2 O 2 ) 1-x (Nd 2 O 3 ) x system. Both solid solution α (0.05≤x≤0.30) and β (0.53≤x≤0.73) belong to the rhombohedral system (R3m). The lattice parameters represented by a hexagonal cell are a=3.9832(4), c=27.536(5) A for Bi 0.8 Nd 0.2 O 1.5 (α phase) and a=3.8826(3), c=9.727(1) A for Bi 0.4 Nd 0.8 O 1.5 (β phase). The Bi 0.55 Nd 0.45 O 1.5 compound crystallizes in a face-centered cubic (f.c.c.) lattice with a=5.5480(2) A. (orig.)

Muon-spin-rotation studies of the temperature dependence of the magnetic penetration depth in the YBa2Cu3Ox family and related compounds

International Nuclear Information System (INIS)

Zimmermann, P.; Keller, H.; Lee, S.L.; Savic, I.M.; Warden, M.; Zech, D.; Cubitt, R.; Forgan, E.M.; Kaldis, E.; Karpinski, J.; Krueger, C.

1995-01-01

A systematic muon-spin-rotation (μ + SR) study is presented of the temperature dependence of the London penetration depth in sintered powder samples of the YBa 2 Cu 3 O x system and related compounds. The in-plane penetration depth λ ab is estimated from the μ + SR depolarization rate of Bi 2 Sr 2 CaCu 2 O 8+δ , YBa 2 Cu 4 O 8 , and a series of samples of the YBa 2 Cu 3 O x family, respectively. It is found that not only the low-temperature value λ ab (0), but also the temperature behavior λ ab (T) is specific to each compound. The form of λ ab (T) can be well characterized by a simple power law. In particular, the YBa 2 Cu 3 O x family shows a systematic variation of the form of λ ab (T) with the oxygen content x which points to a varying coupling strength, whereas λ ab (0) as a function of x suggests a positive charge transfer into the CuO 2 planes with increasing oxygen doping. Furthermore, our data is consistent with an empirical ansatz which has been proposed in the framework of a Bose-gas picture of high-temperature superconductivity. As a consequence, the pressure and the isotope coefficients can be extracted from the μ + SR depolarization rate and compared to direct measurements of these quantities, showing good agreement. Moreover, in the Bose-gas picture the variation of λ ab (T) in the YBa 2 Cu 3 O x family may be interpreted as a crossover from a dense (high-T c ) to a dilute (low-T c ) system of weakly interacting local pairs

Antiferromagnetic Coupling in the Polynuclear Compound [Cu(II) (Allopurinolate) (OH-)] n

Science.gov (United States)

Acevedo-Chávez, Rodolfo; Costas, María. Eugenia; Escudero-Derat, Roberto

1994-11-01

Synthetic, spectral, and magnetic studies of the Cu(II) polynuclear coordination compound [Cu(HL(OH-)]n with bridging OH- and HL (allopurinolate; C5H3N4O-) ligands are reported. The compound is obtained from aqueous media (at several pH values and from CI-, Br-, NO-3, SO2-4, ClO-4, and CH3CO-2 Cu(II) salts), from DMSO at ca. 70°C using several of the above salts, and under refluxing methanol employing Cu(SO4) or Cu(CH3CO2)2. The results suggest that the compound [Cu(HL)(OH-)]n has a polynuclear form in which the bridging allopurinolate is coordinated through the N(1) and N(2) atoms of the pyrazolic moiety. All attempts to grow crystals suitable for X-ray studies were unsuccessful, and an amorphous compound was always obtained. Magnetic studies show the existence of a strong antiferromagnetic coupling, which may be associated with a favorable structural arrangement between the metallic centers and the bridging ligands. This magnetic behavior is remarkable for a Cu(II) polynuclear coordination compound. Spectral and magnetic results together with the coordination modes of the bridging groups let us postulate as a possible arrangement a cyclic polynuclear structure presenting the allopurinolate and OH- bridging ligands in a mutually trans configuration. This work is the first EPR spectral and magnetic study reported for a coordination compound with the allopurinol heterocycle as a ligand and, thus for the first example of a polynuclear coordination compound combining allopurinolate and OH- as bridging groups.

Cu2ZnSnS4 thin films grown by flash evaporation and subsequent annealing in Ar atmosphere

International Nuclear Information System (INIS)

Caballero, R.; Izquierdo-Roca, V.; Merino, J.M.; Friedrich, E.J.; Climent-Font, A.; Saucedo, E.; 2UB, Departament d'Electrònica, Universitat de Barcelona, C. Martí i Franquès 1, E-08028 Barcelona (Spain))" data-affiliation=" (IREC, Catalonia Institute for Energy Research, C. Jardins de les Dones de Negre 1, Sant Adriá del Besòs, E-08930 Barcelona (Spain); IN2UB, Departament d'Electrònica, Universitat de Barcelona, C. Martí i Franquès 1, E-08028 Barcelona (Spain))" >Pérez-Rodríguez, A.; León, M.

2013-01-01

A study of Cu 2 ZnSnS 4 thin films grown by flash evaporation and subsequently annealed in Ar atmosphere has been carried out. Prior to thin film deposition, Cu 2 ZnSnS 4 bulk compounds with stoichiometric and Zn-rich compositions were synthesized as evaporation sources. The characteristics of the bulk compounds and thin films were investigated by X-ray diffraction, Raman spectroscopy, scanning electron microscopy and elastic back scattering. Cu 2 ZnSnS 4 deposited films contain lower concentrations of Zn than the bulk compounds used as evaporation sources, which is related to a preferential Zn re-evaporation during the deposition process. The desired kesterite composition for solar cell applications was achieved by using a Zn-rich compound as the evaporation source plus a thermal treatment at 620 °C in Ar atmosphere. - Highlights: ► Cu 2 ZnSnS 4 (CZTS) thin films by flash evaporation + annealing in Ar atmosphere ► Difficulty of growing a single phase kesterite material ► X-ray diffraction and Raman spectroscopy to identify the different phases ► Importance of the starting film composition to get the desired CZTS material ► Annealing treatment to obtain the optimum material to be used for CZTS solar cells

Bi2O3–CuO–P2O5 system: Two novel compounds built from the intergrowths oxocentered polycationic 1D-ribbons

International Nuclear Information System (INIS)

Colmont, Marie; Endara, Diana; Aliev, Almaz; Terryn, Christine; Huvé, Marielle; Mentré, Olivier

2013-01-01

Single crystals of two novel bismuth copper oxyphosphates were grown from a unique melt. They have been structurally characterized by means of single crystal X-Ray Diffraction (XRD). Bi 29.4 Cu 9.29 O 32 (PO 4 ) 16 Cu 2.63 (1) is orthorhombic, space group Pca2 1 , a=33.0549(2)A, b=11.6991(4)A and c=5.2902(2)A, R 1 =0.059 and wR 2 =0.061. Bi 37.2 Cu 18.8 O 44 (PO 4 ) 24 Cu 5 (2) is orthorhombic, space group Pna2 1 , a=11.6010(3)A, b=47.4384(5)A and c=5.267(2)A, R 1 =0.0940 and wR 2 =0.0981. Both compounds are formed of similar 1D building units (BUs) organized into two different 3D regular intergrowths mediated by phosphate groups. Here, the so-called 1D-BUs are infinite ribbons formed by edge-sharing O(Bi,M) 4 tetrahedra with n=4 and n=3 tetrahedra-wide units. Both compounds were analyzed from the viewpoint of their relationship with the parent δ-Bi 2 O 3 fluorite-like structure, where phosphorus atoms substitutes for some Bi sites. A non-exhaustive review of the related structural types is given. We have checked by second harmonic generacy (SHG) microscopy that the two non-centrosymmetric structures (despite polar subunits) lead to SHG before the samples are irreversibly damaged. - Graphical abstract: This paper reports the crystal structure of two new bismuth oxophosphate compounds. Both are built on the association of n=3 and 4 building unit ribbons surrounded by isolated PO4 tetrahedra and tunnels hosting Cu 2+ cations. They come in addition to the numerous Bi-based compounds already pointed out. Once more, this is the proof of the richness of this crystal system. - Highlights: • Two new bismuth oxophosphates were synthesized. • Crystal structure were solved thanks to single crystal X-Ray diffraction. • They show two different associations of n=3 and 4 ribbons built on [O,(Bi,M) 4 ] tetrahedral sharing edges and surrounded by isolated PO4 groups. • SHG microscopy confirm the NCS character of both compounds. • The family of bismuth oxophosphate

Theoretical investigation of the Fermi surfaces of La2-xSrxCuO4 and YBa2Cu3O7

International Nuclear Information System (INIS)

Antonov, V.N.; Antonov, Vl.N.; Bar'yakhtar, V.G.; Baglyuk, A.I.; Maksimov, E.G.; Nemoshkalenko, V.V.; Perlov, A.Ya.; Savrasov, S.Yu.; Uspenskii, Yu.A.

1989-01-01

A theoretical investigation is made of the shape of the Fermi surface and of the constant-energy surfaces near the Fermi energy of the La 2-x Sr x CuO 4 and YBa 2 Cu 3 O 7 oxides by a self-consistent linear muffin-tin orbital method in the atomic sphere approximation (OMTO-ASA). It is shown that the Fermi surfaces of these compounds are strongly two-dimensional. The Fermi surface of La 2-x Sr x CuO 4 is a corrugated rounded box centered at the point Λ. The Fermi surface of YBa 2 Cu 3 O 7 consists of four sheets: an electron cushion at the point Λ and three nested hole surfaces centered at the point S. The electron cushion and one of the hole surfaces are strongly corrugated along the z direction. The theoretically calculated Fermi surfaces of La 2 CuO 4 and YBa 2 Cu 3 O 7 are compared with the experimental data on electron-positron annihilation

Physicochemical, Spectral, and Biological Studies of Mn(II, Cu(II, Cd(II, Zr(OH2(IV, and UO2(VI Compounds with Ligand Containing Thiazolidin-4-one Moiety

Directory of Open Access Journals (Sweden)

Dinesh Kumar

2014-01-01

Full Text Available The Schiff base (I upon reacting with mercaptoacetic acid in dry benzene undergoes cyclization and forms N-(2-carbamoylthienyl-C-(3′-carboxy-2′-hydroxyphenylthiazolidin-4-one, LH3 (II. A MeOH solution of II reacts with Mn(II, Cu(II, Cd(II, Zr(OH2(IV, and UO2(VI ions and forms the coordination compounds, [Mn(LH(MeOH2], [Cu(LH]2, [Cd(LH], [Zr(OH2(OAc2(LH3], and [UO2(NO3(LH2(MeOH]. The compounds have been characterized on the basis of elemental analyses, molar conductance, molecular weight, spectral (IR, reflectance, and EPR studies and magnetic susceptibility measurements. LH3 behaves as a neutral tridentate ONS donor ligand in [Zr(OH2(OAc2(LH3], monobasic tridentate ONS donor ligand in [UO2(NO3(LH2(MeOH], dibasic tridentate OOS donor ligand in [Cu(LH]2 and dibasic tetradentate OONO donor ligand in [Mn(LH(MeOH2] and [Cd(LH]. [Cu(LH]2 is dimer, while all other compounds are monomers in diphenyl. A square-planar structure for [Cu(LH]2, a tetrahedral structure for [Cd(LH], an octahedral structure for [Mn(LH(MeOH2], a pentagonal-bipyramidal structure for [Zr(OH2(OAc2(LH3], and an eight-coordinate structure for [UO2(NO3(LH2(MeOH] are proposed. The ligand (II and its compounds show antibacterial activities towards E. coli. (Gram negative and S. aureus (Gram positive.

Thermal gravimetric analysis of the CsCuCl3, Cs2CuCl4 and Cs2CuCl4x2H2O crystals

International Nuclear Information System (INIS)

Soboleva, L.V.; Vasil'eva, M.G.

1977-01-01

The thermal characteristics of crystals of Cs 2 CuCl 4 , Cs 2 CuCl 4 x2H 2 O, and CsCuCl 3 were investigated thermogravimetrically. The derivatogram of the Cs 2 CuCl 4 crystal is characterized by the presence of a single endothermal effect at 505 deg C. The derivatogram of the Cs 2 CuCl 4 x2H 2 O crystal contains three endothermal effects: at 40, 135, and 480 deg C. The derivatogram of the CsCuCl 3 crystal shows the presence of two endothermal effects at 142 and 455 deg C. The thermogravimetric data on Cs 2 CuCl 4 and CsCuCl 3 crystals reveal crystal decomposition on melting; hence, these crystals cannot be grown from melts

Bonding in d9 complexes derived from EPR: Application to CuCl2-4, CuBr2-4, and CdCl2:Cu2+

Science.gov (United States)

Aramburu, J. A.; Moreno, M.

1985-12-01

In this work are reported the theoretical expressions for the [g], hyperfine, and superhyperfine (shf) tensors of a d9 square-planar complex within a molecular orbital (MO) scheme. These expressions include contributions arising from crystal field and charge transfer excitations calculated up to third and second order perturbations, respectively. This makes the present framework more general than those previously used. Through those expressions we have derived from the experimental EPR and optical data the MO coefficients corresponding to the valence b1g(x2-y2), b2g(xy), and eg(xz,yz) levels and also the core polarization contribution K to the hyperfine tensor for the systems CuCl2-4, CuBr2-4, and CdCl2:Cu2+. The 3d charge obtained for CuCl2-4 is equal to 0.61, 0.83, and 0.85 for the antibonding 3b1g, 2b2g, and 2eg levels, respectively. These figures are much closer to the Xα results by Bencini and Gatteschi [J. Am. Chem. Soc. 105, 5535 (1983)] than to those by Desjardins et al. [J. Am. Chem. Soc. 105, 4590 (1983)]. The σ and π covalency for CuBr2-4 are both higher than for CuCl2-4 in accord to the lower electronegativity for bromine. However, only for the antibonding 3b1g level of CuBr2-4 have we obtained an electronic charge lying mainly on ligands. The covalency of CdCl2:Cu2+ is smaller than that found for CuCl2-4, a fact associated to a higher metal-ligand distance for the former. Evidence of this statement are also given from the analysis of crystal-field spectra and isotropic shf constant. The values of K derived for CuCl2-4 (128.1×10-4 cm-1), CuBr2-4 (103.6×10-4 cm-1), and CdCl2:Cu2+ (123.9×10-4 cm-1) point out the dependence of K on the equatorial covalency but also on the existence of axial ligands. The [g] tensor of CuBr2-4 is dominated by the charge transfer contribution while the crystal field one is negative. Finally an analysis of the importance of each one of the involved contributions to the spin-Hamiltonian parameters is reported for the

Compounds Containing Tetragonal Cu2+ Complexes: Is the dx2–y2–d3z2–r2 Gap a Direct Reflection of the Distortion?

DEFF Research Database (Denmark)

García-Fernández, Pablo; Barriuso, María Teresa; García Lastra, Juan Maria

2013-01-01

– complex. This internal field, especially important for layered compounds, is shown to explain all puzzling experimental facts on the d–d transitions of the studied systems and is of interest in the search of new Cu2+ and Ag2+ superconducting materials where a strong correlation between Δ...... to be not correct through the study of pure K2CuF4-, KCuF3-, and Cu2+-doped KZnF3 and K2ZnF4 model compounds. Indeed, ab initio calculations prove that Δ in these insulating materials also depends on the internal electric field created by the rest of lattice ions on active electrons confined in a given CuF64...

The periplasmic protein TolB as a potential drug target in Pseudomonas aeruginosa.

Directory of Open Access Journals (Sweden)

Alessandra Lo Sciuto

Full Text Available The Gram-negative bacterium Pseudomonas aeruginosa is one of the most dreaded pathogens in the hospital setting, and represents a prototype of multi-drug resistant "superbug" for which effective therapeutic options are very limited. The identification and characterization of new cellular functions that are essential for P. aeruginosa viability and/or virulence could drive the development of anti-Pseudomonas compounds with novel mechanisms of action. In this study we investigated whether TolB, the periplasmic component of the Tol-Pal trans-envelope protein complex of Gram-negative bacteria, represents a potential drug target in P. aeruginosa. By combining conditional mutagenesis with the analysis of specific pathogenicity-related phenotypes, we demonstrated that TolB is essential for P. aeruginosa growth, both in laboratory and clinical strains, and that TolB-depleted P. aeruginosa cells are strongly defective in cell-envelope integrity, resistance to human serum and several antibiotics, as well as in the ability to cause infection and persist in an insect model of P. aeruginosa infection. The essentiality of TolB for P. aeruginosa growth, resistance and pathogenicity highlights the potential of TolB as a novel molecular target for anti-P. aeruginosa drug discovery.

Pressure-induced metal-insulator transition in spinel compound CuV2S4

International Nuclear Information System (INIS)

Okada, H.; Koyama, K.; Hedo, M.; Uwatoko, Y.; Watanabe, K.

2008-01-01

In order to investigate the pressure effect on electrical properties of CuV 2 S 4 , we performed the electrical resistivity measurements under high pressures up to 8 GPa for a high-quality polycrystalline sample. The charge density wave (CDW) transition temperatures increase with increasing pressure. The residual resistivity rapidly increases with increasing pressure over 4 GPa, and the temperature dependence of the electrical resistivity at 8 GPa exhibits a semiconducting behavior below about 150 K, indicating that a pressure-induced metal-insulator transition occurs in CuV 2 S 4 at 8 GPa

Hydrothermal synthesis and structural characterization of an organic–inorganic hybrid sandwich-type tungstoantimonate [Cu(en)2(H2O)]4[Cu(en)2(H2O)2][Cu2Na4(α-SbW9O33)2]·6H2O

International Nuclear Information System (INIS)

Liu, Yingjie; Cao, Jing; Wang, Yujie; Li, Yanzhou; Zhao, Junwei; Chen, Lijuan; Ma, Pengtao; Niu, Jingyang

2014-01-01

An organic–inorganic hybrid sandwich-type tungstoantimonate [Cu(en) 2 (H 2 O)] 4 [Cu(en) 2 (H 2 O) 2 ][Cu 2 Na 4 (α-SbW 9 O 33 ) 2 ]·6H 2 O (1) has been synthesized by reaction of Sb 2 O 3 , Na 2 WO 4 ·2H 2 O, CuCl 2 ·2H 2 O with en (en=ethanediamine) under hydrothermal conditions and structurally characterized by elemental analysis, inductively coupled plasma atomic emission spectrometry, IR spectrum and single-crystal X-ray diffraction. 1 displays a centric dimeric structure formed by two equivalent trivacant Keggin [α-SbW 9 O 33 ] 9− subunits sandwiching a hexagonal (Cu 2 Na 4 ) cluster. Moreover, those related hexagonal hexa-metal cluster sandwiched tungstoantimonates have been also summarized and compared. The variable-temperature magnetic measurements of 1 exhibit the weak ferromagnetic exchange interactions within the hexagonal (Cu 2 Na 4 ) cluster mediated by the oxygen bridges. - Graphical abstract: An organic–inorganic hybrid (Cu 2 Na 4 ) sandwiched tungstoantimonate [Cu(en) 2 (H 2 O)] 4 [Cu (en) 2 (H 2 O) 2 ][Cu 2 Na 4 (α-SbW 9 O 33 ) 2 ]·6H 2 O was synthesized and magnetic properties was investigated. Display Omitted - Highlights: • Organic–inorganic hybrid sandwich-type tungstoantimonate. • (Cu 2 Na 4 sandwiched) tungstoantimonate [Cu 2 Na 4 (α-SbW 9 O 33 ) 2 ] 10− . • Ferromagnetic tungstoantimonate

Spontaneous electric polarization in the B-site magnetic spinel GeCu2O4

Science.gov (United States)

Yanda, Premakumar; Ghara, Somnath; Sundaresan, A.

2018-04-01

We report the observation of a spontaneous electric polarization at the antiferromagnetic ordering temperature (TN ∼ 33 K) of Cu2+ ions in the B-site magnetic spinel GeCu2O4, synthesized at high pressure and high temperature. This compound is known to crystallize in a tetragonal structure (space group I41/amd) due to Jahn-Teller distortion of Cu2+ ions and exhibit a collinear up-up-down-down (↑↑↓↓) antiferromagnetic spin configuration below TN. We found a clear dielectric anomaly at TN, where an electric polarization appears in the absence of applied magnetic field. The electric polarization is suppressed by applied magnetic fields, which demonstrates that the compound GeCu2O4 is a type-II multiferroic.

Crystal structure and anisotropic magnetic properties of new ferromagnetic Kondo lattice compound Ce(Cu,Al,Si){sub 2}

Energy Technology Data Exchange (ETDEWEB)

Maurya, A.; Thamizhavel, A.; Dhar, S.K. [Department of Condensed Matter Physics & Materials Science, Tata Institute of Fundamental Research, Homi Bhabha Road, Mumbai 400 005 (India); Provino, A.; Pani, M.; Costa, G.A. [Department of Chemistry, University of Genova, Via Dodecaneso 31, 16146 Genova (Italy); Institute SPIN-CNR, Corso Perrone 24, 16152 Genova (Italy)

2017-03-15

Single crystals of the new compound CeCu{sub 0.18}Al{sub 0.24}Si{sub 1.58} have been grown by high-temperature solution growth method using a eutectic Al-Si mixture as flux. This compound is derived from the binary CeSi{sub 2} (tetragonal α-ThSi{sub 2}-type, Pearson symbol tI12, space group I4{sub 1}/amd) obtained by partial substitution of Si by Cu and Al atoms but showing full occupation of the Si crystal site (8e). While CeSi{sub 2} is a well-known valence-fluctuating paramagnetic compound, the CeCu{sub 0.18}Al{sub 0.24}Si{sub 1.58} phase orders ferromagnetically at T{sub C}=9.3 K. At low temperatures the easy-axis of magnetization is along the a-axis, which re-orients itself along the c-axis above 30 K. The presence of hysteresis in the magnetization curve, negative temperature coefficient of resistivity at high temperatures, reduced jump in the heat capacity and a relatively lower entropy released up to the ordering temperature, and enhanced Sommerfeld coefficient (≈100 mJ/mol K{sup 2}) show that CeCu{sub 0.18}Al{sub 0.24}Si{sub 1.58} is a Kondo lattice ferromagnetic, moderate heavy fermion compound. Analysis of the high temperature heat capacity data in the paramagnetic region lets us infer that the crystal electric field split doublet levels are located at 178 and 357 K, respectively, and Kondo temperature (8.4 K) is of the order of T{sub C} in CeCu{sub 0.18}Al{sub 0.24}Si{sub 1.58}.

Characteristics of chemical bond and vacancy formation in chalcopyrite-type CuInSe2 and related compounds

International Nuclear Information System (INIS)

Maeda, Tsuyoshi; Wada, Takahiro

2009-01-01

We studied characteristics of chemical bond and vacancy formation in chalcopyrite-type CuInSe 2 (CIS) by first principles calculations. The chalcopyrite-type CIS has two kinds of chemical bonds, Cu-Se and In-Se. The Cu-Se bond is a weak covalent bonding because electrons occupy both bonding and antibonding orbitals of Cu 3d and Se 4p and occupy only the bonding orbital (a 1 ) of Cu 4s and Se 4p and do not occupy the antibonding orbital (a 1 * ) of Cu 4s and Se 4p. On the other hand, the In-Se bond has a partially covalent and partially ionic character because the In 5s orbital covalently interacts with Se 4p; the In 5p orbital is higher than Se 4p and so the electron in the In 5p orbital moves to the Se 4p orbital. The average bond order of the Cu-Se and In-Se bonds can be calculated to be 1/4 and 1, respectively. The bond order of Cu-Se is smaller than that of In-Se. The characteristics of these two chemical bonds are related to the formation of Cu and In vacancies in CIS. The formation energy of the Cu vacancy is smaller than that of the In vacancy under both Cu-poor and In-poor conditions. The displacement (Δl) of the surrounding Se atoms after the formation of the Cu vacancy is smaller than the Δl after the formation of the In vacancy. The interesting and unique characteristics of CIS are discussed on the basis of the characteristics of the chemical bond. (copyright 2009 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

La{sub 3}Cu{sub 4}P{sub 4}O{sub 2} and La{sub 5}Cu{sub 4}P{sub 4}O{sub 4}Cl{sub 2}. Synthesis, structure and {sup 31}P solid state NMR spectroscopy

Energy Technology Data Exchange (ETDEWEB)

Bartsch, Timo; Eul, Matthias; Poettgen, Rainer [Muenster Univ. (Germany). Inst. fuer Anorganische und Analytische Chemie; Benndorf, Christopher; Eckert, Hellmut [Muenster Univ. (Germany). Inst. fuer Physikalische Chemie; Sao Paulo Univ., Sao Carlos, SP (Brazil). Inst. of Physics

2016-04-01

The phosphide oxides La{sub 3}Cu{sub 4}P{sub 4}O{sub 2} and La{sub 5}Cu{sub 4}P{sub 4}O{sub 4}Cl{sub 2} were synthesized from lanthanum, copper(I) oxide, red phosphorus, and lanthanum(III) chloride through a ceramic technique. Single crystals can be grown in a NaCl/KCl flux. Both structures were refined from single crystal X-ray diffractometer data: I4/mmm, a = 403.89(4), c = 2681.7(3) pm, wR2 = 0.0660, 269 F{sup 2} values, 19 variables for La{sub 3}Cu{sub 4}P{sub 4}O{sub 2} and a = 407.52(5), c = 4056.8(7) pm, wR2 = 0.0905, 426 F{sup 2} values, 27 variables for La{sub 5}Cu{sub 4}P{sub 4}O{sub 4}Cl{sub 2}. Refinement of the occupancy parameters revealed full occupancy for the oxygen sites in both compounds. The structures are composed of cationic (La{sub 2}O{sub 2}){sup 2+} layers and covalently bonded (Cu{sub 4}P{sub 4}){sup 5-} polyanionic layers with metallic characteristics, and an additional La{sup 3+} between two adjacent (Cu{sub 4}P{sub 4}){sup 5-} layers. The structure of La{sub 5}Cu{sub 4}P{sub 4}O{sub 4}Cl{sub 2} comprises two additional LaOCl slabs per unit cell. Temperature-dependent magnetic susceptibility studies revealed Pauli paramagnetism. The phosphide substructure of La{sub 3}Cu{sub 4}P{sub 4}O{sub 2} was studied by {sup 31}P solid state NMR spectroscopy. By using a suitable dipolar re-coupling approach the two distinct resonances belonging to the P{sub 2}{sup 4-} and the P{sup 3-} units could be identified.

Theoretical investigation of the Fermi surface of La2-xSrxCuO4 and YBa2Cu3O7

International Nuclear Information System (INIS)

Antonov, V.N.; Antonov, V.N.; Bar'yakhtar, V.G.

1989-01-01

The theoretical investigation of both the Fermi surface (FS) form and isoenergetic surfaces near the Fermi energy of La 2-x Sr x CuO 4 and YBa 2 Cu 3 O 7 is carried out by selfconsistent LMTO/method in an atomic sphere approximation. The FS of these compounds is established to have an essential two-dimensional character. The FS La 2 CuO 4 is a corrugated rounded box centered in Γ point. The FS YBa 2 Cu 3 O 7 consists of four plates: an electron ''cushion'' in Γ point and three embeded hole surfaces centered in S point. In this case the ''cushion'' and one of the hole surfaces are vigorously corrugated along the z-direction. A comparison between both the FS calculated theoretically of La 2 CuO 4 and YBa 2 Cu 3 O 7 and experimental data on electron-positron annihilation is carried out. The electron-rate maps and numerical results of various characteristics, i.e., plate areas, mean rates, mean squares of the rates, partial densities of states for each plate of the FS YBa 2 Cu 3 O 7 are given

Preparation of ZnO/Cu2O compound photocatalyst and application in treating organic dyes

International Nuclear Information System (INIS)

Xu Chao; Cao Lixin; Su Ge; Liu Wei; Liu Hui; Yu Yaqin; Qu Xiaofei

2010-01-01

ZnO/Cu 2 O compound photocatalysts were prepared by 'soak-deoxidize-air oxidation' with different concentrations of Cu 2+ (0.125, 0.25, 0.5, 1, 1.5 and 2 mol/L). The prepared ZnO/Cu 2 O samples were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), energy-dispersive spectrometer (EDS), UV-vis diffuse reflectance spectrometer, and photochemical reaction instrument. The results show that ZnO was hexagonal wurtzite structure and the crystallinity had no change with the increase of Cu 2+ concentration. Cu 2 O belonged to cubic structure and the crystallinity increased with the increase of Cu 2+ concentration. ZnO were rods and bulks which had diameter of about 300-400 nm, some small round Cu 2 O particles which had a diameter of about 50 nm adhered to these rods and bulks. In the compounds the mole ratio of Cu 2 O to ZnO was 0.017, 0.025, 0.076, 0.137, 0.138, and 0.136, respectively. An absorbance in the visible light region between 400 and 610 nm was seen and the reflection rate became less with the mole ratio of Cu 2 O to ZnO increasing. The photocatalytic activities of ZnO/Cu 2 O compound were evaluated using a basic organic dye, methyl orange (MO). It was found that, compared with pure ZnO, the photocatalytic properties of ZnO/Cu 2 O compound were improved greatly and some compounds were better than pure Cu 2 O.

2,2,3,3,5,5,6,6-Octa-p-tolyl-1,4-dioxa-2,3,5,6-tetragermacyclohexane dichloromethane disolvate

Directory of Open Access Journals (Sweden)

Monika L. Amadoruge

2009-09-01

Full Text Available The title compound, C56H56Ge4O2·2CH2Cl2 or Tol8Ge4O2·2CH2Cl2 (Tol = p-CH3C6H4, was obtained serendipitously during the attempted synthesis of a branched oligogermane from Tol3GeNMe2 and PhGeH3. The molecule contains an inversion center in the middle of the Ge4O2 ring which is in a chair conformation. The Ge—Ge bond distance is 2.4418 (5 Å and the Ge—O bond distances are 1.790 (2 and 1.785 (2 Å. The torsion angles within the Ge4O2 ring are −56.7 (1 and 56.1 (1° for the Ge—Ge—O—Ge angles and −43.9 (1° for the O—Ge—Ge—O angle.

Insulators containing CuCl4X22- (X=H2O, NH3) units: Origin of the orthorhombic distortion observed only for CuCl4(H2O)22-

DEFF Research Database (Denmark)

García-Fernández, P.; García Lastra, Juan Maria; Trueba, A.

2012-01-01

The origin of the difference in structure between compounds containing CuCl4X22- (X=H2O, NH3) units is analyzed by means of first-principles calculations. While NH3-containing compounds display tetragonal symmetry, H2O-containing ones display an orthorhombic distortion at low temperature where...... the equatorial Cl- ions are no longer equivalent. Our simulations of optical and vibrational transitions show good agreement with all available experimental optical absorption and Raman data. As a salient feature, the value of the force constant for the B1g mode, K(B1g), driving the orthorhombic distortion......CuCl4(H2O)2 has a local origin....

Fingerprints of field-induced Berezinskii–Kosterlitz–Thouless transition in quasi-two-dimensional S=1/2 Heisenberg magnets Cu(en)(H2O)2SO4 and Cu(tn)Cl2

International Nuclear Information System (INIS)

Baranová, Lucia; Orendáčová, Alžbeta; Čižmár, Erik; Tarasenko, Róbert; Tkáč, Vladimír; Orendáč, Martin; Feher, Alexander

2016-01-01

Organo-metallic compounds Cu(en)(H 2 O) 2 SO 4 (en=C 2 H 8 N 2 ) and Cu(tn)Cl 2 (tn=C 3 H 10 N 2 ) representing S=1/2 quasi-two-dimensional Heisenberg antiferromagnets with an effective intra-layer exchange coupling J/k B ≈3 K, have been examined by specific heat measurements at temperatures down to nominally 50 mK and magnetic fields up to 14 T. A comparative analysis of magnetic specific heat in zero magnetic field revealed nearly identical contribution of short-range magnetic correlations and significant differences were observed at lowest temperatures. A phase transition to long-range order was observed in Cu(en)(H 2 O) 2 SO 4 at T C =0.9 K while hidden in Cu(tn)Cl 2 . A response of both compounds to the application of magnetic field has rather universal features characteristic for a field-induced Berezinskii–Kosterlitz–Thouless transition theoretically predicted for ideal two-dimensional magnets. - Highlights: • Magnetic specific heat of Cu(en)(H 2 O) 2 SO 4 (1) and Cu(tn)Cl 2 (2) was analysed. • In zero magnetic field, (1) and (2) behave as quasi-two-dimensional magnets. • We observed universal thermodynamic response of (1) and (2) to applied field. • Features of field-induced Berezinskii–Kosterlitz–Thouless transition were detected.

Investigations in anhydrous liquid ammonia. Reaction of group 2, 4, 5, 11 metal and actinoids compounds

International Nuclear Information System (INIS)

Woidy, Patrick

2014-01-01

The solubility and reactivity of metal halides, transition metal halides, and actinoid halides in liquid ammonia can lead to new starting materials for the synthesis of fluorides in low oxidation states or for nitrides via a ''low-temperature route''. In this context the ability of metal and actinoid halides to act as an acceptor for or donor of fluoride ions is also of interest. Four different systems were investigated in this study. In the first section, the synthesis and characterization of new compounds were carried out in the system CuX/NH 3 (X = F, Cl, Br, I, and CN) and lead to a ligand stabilized monovalent copper fluoride as a main result. In the second section, the solubility of uranyl compounds and uranium halides in liquid ammonia was investigated and the products were characterized. In the third section, alkali metal thorates were synthesized. Their solubility in liquid ammonia and their behavior as an acceptor for fluoride ions was investigated. In the last section, the results on the solubility behavior of transition metal halides in liquid ammonia and their coordination behavior are presented. In the first system CuX/NH 3 several new compounds, such as [Cu(NH 3 ) 3 ]X (X = Br, I or CN) were synthesized and characterized. The reactions of this compounds with fluoride ion donors (NH 4 F or Me 4 NF) led unfortunately not to the monovalent copper fluoride CuF. The comproportionation reaction of Cu and CuF 2 in liquid ammonia lead to the compounds [Cu(NH 3 ) 3 ] 2 [Cu 2 (NH 3 ) 2 ] . 4 NH 3 and [Cu(NH 3 ) 2 ]F . NH 3 . For the preparation of binary CuF, various decomposition experiments were executed on the compound [Cu(NH 3 ) 2 ]F . NH 3 which resulted in different decomposition products. In additional studies various complexes of divalent copper was investigated and with the compound [Cu(NH 3 ) 5 ]F 2 . NH 3 the solubility of fluoride containing substances in liquid ammonia could be shown. Studies of six- and tetravalent uranium

Effect of Pressure on the Ferromagnetic Cerium Compound CeCu9Sn4

International Nuclear Information System (INIS)

Ishii, Y.; Mori, N.; Hedo, M.; Uwatoko, Y.

2003-01-01

Electrical resistivity measurements under hydrostatic pressure up to 2.2 GPa was carried out for a ferromagnetic ternary cerium compound CeCu 9 Sn 4 . The ferromagnetic transition temperature increases with increasing pressure up to 0.8 GPa and then decreases with increasing pressure above 1 GPa. Origins of this pressure dependence may be the competition between magnetic interaction in the c-plane and along the c-direction. (author)

Mono(p-tolyl)platinum(II) and bis(p-tolyl)platinum(II) complexes of diethylsulfide as reagents for organoplatinum synthesis. Structures of [Pt(p-Tol)2(µ-SEt2)]2 and PtCl(p-Tol)(bpy) (bpy = 2,2'-bipyridine)

NARCIS (Netherlands)

Koten, G. van; Casado Lacabra, M.A.; Canty, A.J.; Lutz, M.H.; Patel, J.; Spek, A.L.; Sun, H.

2001-01-01

The complex trans-PtCl(p-Tol)(SEt{2}){2} is obtained from the reaction of [Pt(p-Tol){2}(SEt{2})]{2} with PtCl{2}(SEt{2}){2} and SEt{2} in mole ratio 1:2:2. The mono(p-tolyl)platinum(II) and bis(p-tolyl)platinum(II) complexes of diethylsulfide react with 2, 2'-bipyridine to form the complexes

The crystal structure of paramagnetic copper(ii) oxalate (CuC2O4):

DEFF Research Database (Denmark)

Christensen, Axel Nørlund; Lebech, Bente; Andersen, Niels Hessel

2014-01-01

Synthetic copper(ii) oxalate, CuC2O4, was obtained in a precipitation reaction between a copper(ii) solution and an aqueous solution of oxalic acid. The product was identified from its conventional X-ray powder patterns which match that of the copper mineral Moolooite reported to have...... the composition CuC2O4·0.44H2O. Time resolved in situ investigations of the thermal decomposition of copper(ii) oxalate using synchrotron X-ray powder diffraction showed that in air the compound converts to Cu2O at 215 °C and oxidizes to CuO at 345 °C. Thermo gravimetric analysis performed in an inert Ar....... The crystal structure consists of a random stacking of CuC2O4 micro-crystallites where half the Cu-atoms are placed at (2a) and the other half at (2b) positions with the corresponding oxalate molecules centred around the corresponding (2b) and (2a) site positions, respectively. The diffraction patterns...

Tuning of magnetic frustration in S = 1 / 2 Kagomé lattices {[Cu3(CO3)2(bpe)3](CLO4)2}n and {[Cu3(CO3)2(bpy)3](CLO4)2}n through rigid and flexible ligands

Science.gov (United States)

Ajeesh, M. O.; Yogi, A.; Padmanabhan, M.; Nath, R.

2015-04-01

Single crystalline and polycrystalline samples of S = 1 / 2 Kagomé lattices { [Cu3(CO3)2(bpe)3 ](CLO4)2 } n and { [Cu3(CO3)2(bpy)3 ](CLO4)2 } n, respectively were synthesized. Their structural and magnetic properties were characterized by means of x-ray diffraction and magnetization measurements. Both compounds crystalize in a hexagonal structure (space group P-6) consisting of CuO4 Kagomé layers in the ab-plane but linked along c direction through either rigid bpy or flexible bpe ligands to form 3D frame works. Magnetic measurements reveal that both the compounds undergo ferromagnetic ordering (TC) at low temperatures and the TC and the extent of frustration could be tuned by changing the nature of the pillar ligands. {[Cu3(CO3)2(bpe)3](CLO4)2}n which is made up of flexible bpe ligands has a TC of 5.7 K and a Curie-Weiss temperature (θCW) of -39.7 K giving rise to a frustration parameter of |θCW | /TC ≃ 6.96. But the replacement of bpe by a more rigid and electronically delocalized bpy ligand leads to an enhanced TC ≃ 9.3 K and a reduced frustration parameter of |θCW | /TC ≃ 3.54.

AcrA suppressor alterations reverse the drug hypersensitivity phenotype of a TolC mutant by inducing TolC aperture opening

Science.gov (United States)

Weeks, Jon W.; Celaya-Kolb, Teresa; Pecora, Sara; Misra, Rajeev

2010-01-01

Summary In Escherichia coli, the TolC–AcrAB complex forms a major antibiotic efflux system with broad substrate specificity. During the complex assembly, the periplasmic helices and bottom turns of TolC are thought to interact with a hairpin helix of AcrA and hairpin loops of AcrB respectively. In the present study we show that a four-residue substitution in TolC’s turn 1, which connects outer helices 3 and 4 proximal to TolC’s periplasmic aperture, confers antibiotic hypersensitivity without affecting TolC-mediated phage or colicin infection. However, despite the null-like drug sensitivity phenotype, chemical cross-linking analysis revealed no apparent defects in the ability of the mutant TolC protein to physically interact with AcrA and AcrB. A role for TolC turn 1 residues in the functional assembly of the tripartite efflux pump complex was uncovered through isolating suppressor mutations of the mutant TolC protein that mapped within acrA and by utilizing a labile AcrA protein. The data showed that AcrA-mediated suppression of antibiotic sensitivity was achieved by dilating the TolC aperture/channel in an AcrB-dependent manner. The results underscore the importance of the periplasmic turn 1 of TolC in the functional assembly of the tripartite efflux complex and AcrA in transitioning TolC from its closed to open state. PMID:20132445

Mixed-Spin Diamond Chain Cu2FePO4F4(H2O)4 with a Noncollinear Spin Order and Possible Successive Phase Transitions.

Science.gov (United States)

Lu, Hongcheng; Hayashi, Naoaki; Matsumoto, Yuki; Takatsu, Hiroshi; Kageyama, Hiroshi

2017-08-07

A diamond spin chain system, one of the one-dimensional frustrated lattices, is known to exhibit novel properties, but experimental studies have been exclusively confined to materials with a single spin component. Here, we report on the synthesis, structure, and magnetic properties of a new diamond chain compound Cu 2 FePO 4 F 4 (H 2 O) 4 1 composed of mixed-spins of Cu 2+ (S = 1/2 × 2) and Fe 3+ (S = 5/2). Compound 1 crystallizes in the space group C2/c of the monoclinic crystal system with a = 7.7546(4) Å, b = 12.1290(6) Å, c = 9.9209(6) Å, β = 105.29(1)°, and Z = 4. DC magnetization, Mössbauer spectroscopy, and heat capacity measurements revealed an antiferromagnetic order at 11.3 K with a small ferromagnetic component. It is suggested that ferrimagnetic diamond chains are arranged in an antiferromagnetic fashion (i.e., [...Fe(↑)-2Cu(↓↓)-Fe(↑)...] and [...Fe(↓)-2Cu(↑↑)-Fe(↓)...]) within the ab plane to cancel net magnetization, and the spin orientation of the diamond chains changes alternately along the c axis due to the magnetic anisotropy, leading to a noncollinear spin order. Furthermore, another anomaly is observed in the heat capacity at around 3 K, suggesting a successive magnetic transition or crossover due to competing magnetic interactions.

Optical properties of La2CuO4 and La2−xCaxCuO4 crystallites in UV–vis–NIR region synthesized by sol–gel process

International Nuclear Information System (INIS)

Li Yifeng; Huang Jianfeng; Cao Liyun; Wu Jianpeng; Fei Jie

2012-01-01

La 2 CuO 4 and La 2−x Ca x CuO 4 crystallites were prepared via a simple sol–gel process. The as-prepared La 2 CuO 4 and La 2 −x Ca x CuO 4 crystallites were characterized by X-ray diffraction, transmission electron microscope and UV–vis–NIR spectra. Results show that the grain size of La 2 CuO 4 crystallites increases with the increase of heat treatment temperature from 600 °C to 800 °C. Optical properties show that La 2 CuO 4 crystallites have broad absorption both in the UV–vis region and in the NIR region. The band gap of the as-prepared crystallites decreases from 1.367 eV to 1.284 eV with the increase of calcination temperature from 600 °C to 800 °C. In the series of La 2−x Ca x CuO 4 compounds (x = 0.05, 0.08, 0.10, 0.12, 0.15 and 0.20), all of the samples exhibit an orthogonal crystal structure and the solubility limit of Ca 2+ in La 2 CuO 4 is within the range of x = 0.12–0.15. In the whole UV–vis–NIR region, La 2−x Ca x CuO 4 crystallites exhibit a broad absorption and the corresponding band gap first increases and then decreases with increasing of Ca 2+ content. - Highlights: ► The optical band gap can be tuned by adjusting the grain size and Ca 2+ content. ► La 2 CuO 4 crystallites exhibit a broad absorption band both in the UV–vis region and in the NIR region. ► The band gap increases from 1.284 eV to 1.319 eV with the decrease of heat treatment temperature. ► In the whole UV–vis–NIR region, the La 2−x Ca x CuO 4 crystallites displayed a broad absorption. ► The band gap of La 2−x Ca x CuO 4 increases linearly with doping level when 0 ≤ x ≤ 0.12.

Study of the magnetic phase transitions and magnetocaloric effect in Dy{sub 2}Cu{sub 2}In compound

Energy Technology Data Exchange (ETDEWEB)

Zhang, Yikun, E-mail: ykzhang10@hotmail.com [State Key Laboratory of Advanced Special Steels, Shanghai University, Shanghai, 200072 (China); Shanghai Key Laboratory of Advanced Ferrometallurgy, Shanghai University, Shanghai, 200072 (China); School of Materials Science and Engineering, Shanghai University, 200072 (China); Institute of Materials Physics, University of Münster, Wilhelm-Klemm-Straße 10, D-48149, Münster (Germany); Xu, Xiao; Yang, Yang; Hou, Long; Ren, Zhongming [State Key Laboratory of Advanced Special Steels, Shanghai University, Shanghai, 200072 (China); Shanghai Key Laboratory of Advanced Ferrometallurgy, Shanghai University, Shanghai, 200072 (China); School of Materials Science and Engineering, Shanghai University, 200072 (China); Li, Xi, E-mail: lx_net@sina.com [State Key Laboratory of Advanced Special Steels, Shanghai University, Shanghai, 200072 (China); Shanghai Key Laboratory of Advanced Ferrometallurgy, Shanghai University, Shanghai, 200072 (China); School of Materials Science and Engineering, Shanghai University, 200072 (China); Wilde, Gerhard [Institute of Materials Physics, University of Münster, Wilhelm-Klemm-Straße 10, D-48149, Münster (Germany)

2016-05-15

The magnetic properties and magnetocaloric effect (MCE) in Dy{sub 2}Cu{sub 2}In compound have been investigated. Dy{sub 2}Cu{sub 2}In undergoes two magnetic phase transitions, a paramagnetic to ferromagnetic (FM) at T{sub C} ∼ 49.5 K followed by a spin reorientation (SR) at T{sub SR} ∼ 19.5 K. For a magnetic field change of 0–7 T, the maximum values of the magnetic entropy change (−ΔS{sub M}{sup max}) are estimated to be 16.5 around T{sub C} and 6.7 J/kg K around T{sub SR} with a large relative cooling power (RCP) value of 617 J/kg. The modified Arrott plots and universal curves of the rescaled ΔS{sub M} confirmed that the magnetic phase transitions in Dy{sub 2}Cu{sub 2}In compound belongs the second order phase transitions. The present results may provide some clues to search for new magnetocaloric materials belonging to RE{sub 2}T{sub 2}X system. - Highlights: • Magnetic properties and magnetocaloric effect in Dy{sub 2}Cu{sub 2}In was studied. • The Dy{sub 2}Cu{sub 2}In undergoes 2 s order magnetic phase transitions. • A large reversible MCE was observed in Dy{sub 2}Cu{sub 2}In. • The origin of MCE and its potential application in Dy{sub 2}Cu{sub 2}In were discussed.

Radiation-induced amorphization of intermetallic compounds: A molecular-dynamics study of CuTi and Cu4Ti3

International Nuclear Information System (INIS)

Lam, N.Q.; Okamoto, P.R.; Sabochick, M.J.

1991-06-01

In the present paper, important results of our recent computer simulation of radiation-induced amorphization in the ordered compounds CuTi and Cu 4 Ti 3 are summarized. The energetic, structural, thermodynamic and mechanical responses of these intermetallics during chemical disordering, point-defect production and heating were simulated, using molecular dynamics and embedded-atom potentials. From the atomistic details obtained, the critical role of radiation-induced structural disorder in driving the crystalline-to-amorphous phase transformation is discussed. 25 refs., 4 figs

Cu{sub 2}ZnSnS{sub 4} thin films grown by flash evaporation and subsequent annealing in Ar atmosphere

Energy Technology Data Exchange (ETDEWEB)

Caballero, R., E-mail: raquel.caballero@uam.es [Universidad Autónoma de Madrid, Departamento de Física Aplicada, M12, C/Francisco Tomás y Valiente 7, E-28049 Madrid (Spain); Izquierdo-Roca, V. [IREC, Catalonia Institute for Energy Research, C. Jardins de les Dones de Negre 1, Sant Adriá del Besòs, E-08930 Barcelona (Spain); Merino, J.M.; Friedrich, E.J. [Universidad Autónoma de Madrid, Departamento de Física Aplicada, M12, C/Francisco Tomás y Valiente 7, E-28049 Madrid (Spain); Climent-Font, A. [Universidad Autónoma de Madrid, Departamento de Física Aplicada, M12, C/Francisco Tomás y Valiente 7, E-28049 Madrid (Spain); CMAM, Universidad Autónoma de Madrid, C/Faraday 3, E-28049, Madrid (Spain); Saucedo, E. [IREC, Catalonia Institute for Energy Research, C. Jardins de les Dones de Negre 1, Sant Adriá del Besòs, E-08930 Barcelona (Spain); Pérez-Rodríguez, A. [IREC, Catalonia Institute for Energy Research, C. Jardins de les Dones de Negre 1, Sant Adriá del Besòs, E-08930 Barcelona (Spain); IN" 2UB, Departament d' Electrònica, Universitat de Barcelona, C. Martí i Franquès 1, E-08028 Barcelona (Spain); León, M. [Universidad Autónoma de Madrid, Departamento de Física Aplicada, M12, C/Francisco Tomás y Valiente 7, E-28049 Madrid (Spain)

2013-05-01

A study of Cu{sub 2}ZnSnS{sub 4} thin films grown by flash evaporation and subsequently annealed in Ar atmosphere has been carried out. Prior to thin film deposition, Cu{sub 2}ZnSnS{sub 4} bulk compounds with stoichiometric and Zn-rich compositions were synthesized as evaporation sources. The characteristics of the bulk compounds and thin films were investigated by X-ray diffraction, Raman spectroscopy, scanning electron microscopy and elastic back scattering. Cu{sub 2}ZnSnS{sub 4} deposited films contain lower concentrations of Zn than the bulk compounds used as evaporation sources, which is related to a preferential Zn re-evaporation during the deposition process. The desired kesterite composition for solar cell applications was achieved by using a Zn-rich compound as the evaporation source plus a thermal treatment at 620 °C in Ar atmosphere. - Highlights: ► Cu{sub 2}ZnSnS{sub 4} (CZTS) thin films by flash evaporation + annealing in Ar atmosphere ► Difficulty of growing a single phase kesterite material ► X-ray diffraction and Raman spectroscopy to identify the different phases ► Importance of the starting film composition to get the desired CZTS material ► Annealing treatment to obtain the optimum material to be used for CZTS solar cells.

Bi{sub 2}O{sub 3}–CuO–P{sub 2}O{sub 5} system: Two novel compounds built from the intergrowths oxocentered polycationic 1D-ribbons

Energy Technology Data Exchange (ETDEWEB)

Colmont, Marie, E-mail: marie.colmont@ensc-lille.fr [Universite Lille 1, Universite Lille Nord France, ENSCL, CNRS, UCCS, UMR 8181, F-59652 Villeneuve d' Ascq (France); Endara, Diana; Aliev, Almaz [Universite Lille 1, Universite Lille Nord France, ENSCL, CNRS, UCCS, UMR 8181, F-59652 Villeneuve d' Ascq (France); Terryn, Christine [Plateforme Imagerie Cellulaire et Tissulaire, 51 Rue Cognacq-Jay, 51100 Reims (France); Huvé, Marielle; Mentré, Olivier [Universite Lille 1, Universite Lille Nord France, ENSCL, CNRS, UCCS, UMR 8181, F-59652 Villeneuve d' Ascq (France)

2013-07-15

Single crystals of two novel bismuth copper oxyphosphates were grown from a unique melt. They have been structurally characterized by means of single crystal X-Ray Diffraction (XRD). Bi{sub 29.4}Cu{sub 9.29}O{sub 32}(PO{sub 4}){sub 16}Cu{sub 2.63} (1) is orthorhombic, space group Pca2{sub 1}, a=33.0549(2)A, b=11.6991(4)A and c=5.2902(2)A, R{sub 1}=0.059 and wR{sub 2}=0.061. Bi{sub 37.2}Cu{sub 18.8}O{sub 44}(PO{sub 4}){sub 24}Cu{sub 5} (2) is orthorhombic, space group Pna2{sub 1}, a=11.6010(3)A, b=47.4384(5)A and c=5.267(2)A, R{sub 1}=0.0940 and wR{sub 2}=0.0981. Both compounds are formed of similar 1D building units (BUs) organized into two different 3D regular intergrowths mediated by phosphate groups. Here, the so-called 1D-BUs are infinite ribbons formed by edge-sharing O(Bi,M){sub 4} tetrahedra with n=4 and n=3 tetrahedra-wide units. Both compounds were analyzed from the viewpoint of their relationship with the parent δ-Bi{sub 2}O{sub 3} fluorite-like structure, where phosphorus atoms substitutes for some Bi sites. A non-exhaustive review of the related structural types is given. We have checked by second harmonic generacy (SHG) microscopy that the two non-centrosymmetric structures (despite polar subunits) lead to SHG before the samples are irreversibly damaged. - Graphical abstract: This paper reports the crystal structure of two new bismuth oxophosphate compounds. Both are built on the association of n=3 and 4 building unit ribbons surrounded by isolated PO4 tetrahedra and tunnels hosting Cu{sup 2+} cations. They come in addition to the numerous Bi-based compounds already pointed out. Once more, this is the proof of the richness of this crystal system. - Highlights: • Two new bismuth oxophosphates were synthesized. • Crystal structure were solved thanks to single crystal X-Ray diffraction. • They show two different associations of n=3 and 4 ribbons built on [O,(Bi,M){sub 4}] tetrahedral sharing edges and surrounded by isolated PO4 groups. • SHG

Compound cuing in free recall.

Science.gov (United States)

Lohnas, Lynn J; Kahana, Michael J

2014-01-01

According to the retrieved context theory of episodic memory, the cue for recall of an item is a weighted sum of recently activated cognitive states, including previously recalled and studied items as well as their associations. We show that this theory predicts there should be compound cuing in free recall. Specifically, the temporal contiguity effect should be greater when the 2 most recently recalled items were studied in contiguous list positions. A meta-analysis of published free recall experiments demonstrates evidence for compound cuing in both conditional response probabilities and interresponse times. To help rule out a rehearsal-based account of these compound cuing effects, we conducted an experiment with immediate, delayed, and continual-distractor free recall conditions. Consistent with retrieved context theory but not with a rehearsal-based account, compound cuing was present in all conditions, and was not significantly influenced by the presence of interitem distractors.

Vibrational spectroscopic and theoretical study of 3,5-dimethyl-1-thiocarboxamide pyrazole (L) and the complexes Co2L2Cl4, Cu2L2Cl4 and Cu2L2Br2

International Nuclear Information System (INIS)

Nemcsok, Denes; Kovacs, Attila; Szecsenyi, Katalin Meszaros; Leovac, Vukadin M.

2006-01-01

In the present paper we report a joint experimental and theoretical study of 3,5-dimethyl-1-thiocarboxamide pyrazole (L) and its complexes Co 2 L 2 Cl 4 , Cu 2 L 2 Cl 4 and Cu 2 L 2 Br 2 . DFT computations were used to model the structural and bonding properties of the title compounds as well as to derive a reliable force field for the normal coordinate analysis of L. The computations indicated the importance of hydrogen bonding interactions in stabilising the global minimum structures on the potential energy surfaces. In contrast to the S-bridged binuclear Cu 2 L 2 Br 2 complex found in the crystal, our computations predicted the formation of (CuLBr) 2 dimers in the isolated state stabilized by very strong (53 kJ/mol) N-H...Br hydrogen bonding interactions. On the basis of FT-IR and FT-Raman experiments and the DFT-derived scaled quantum mechanical force field we carried out a complete normal coordinate analysis of L. The FT-IR spectra of the three complexes were interpreted using the present assignment of L, literature data and computed results

On the superconductivity of doped La2 Cu O4

International Nuclear Information System (INIS)

Vasiliu-Doloc, L.; Apostol, M.

1992-01-01

The superconducting critical temperature and the oxygen isotope shift are analyzed as functions of the doping level x for both La 2-x Sr x Cu O 4 and La 2-x Ba x Cu O 4 within the framework of the theory of high-temperature superconductivity that assumes a coupling between the charge carriers and the oxygen-displacive modes of the lattice. It is shown that an energy gap in the electronic structure at q = ± π/4 (1,±1,0) would markedly depress the critical temperature around x = 1/8 , as for low-temperature tetragonal phase of La 2-x Ba x Cu O 4 , even in the absence of the Fermi surface nesting. On the other hand, a slight reduction in the coupling strength of the model, which may arise in the narrow range around x = 0.12, implies an increase in the oxygen-mass exponent of the lattice frequencies, a decrease in the isotope shift of the critical temperature and a depression of the critical temperature as observed experimentally for both compounds. (Author)

Quick photo-Fenton degradation of phenolic compounds by Cu/Al2O3-MCM-41 under visible light irradiation: small particle size, stabilization of copper, easy reducibility of Cu and visible light active material.

Science.gov (United States)

Pradhan, Amaresh C; Nanda, Binita; Parida, K M; Das, Mira

2013-01-14

The present study reports the photo-Fenton degradation of phenolic compounds (phenol, 2-chloro-4-nitrophenol and 4-chloro-2-nitrophenol) in aqueous solution using mesoporous Cu/Al(2)O(3)-MCM-41 nanocomposite as a heterogeneous photo-Fenton-like catalyst. The in situ incorporation of mesoporous Al(2)O(3) (MA) into the framework of MCM-41 (sol-gel method) forms Al(2)O(3)-MCM-41 and wetness impregnation of Cu(II) on Al(2)O(3)-MCM-41 generates mesoporous Cu/Al(2)O(3)-MCM-41 composite. The effects of pH and H(2)O(2) concentration on degradation of phenol, 2-chloro-4-nitrophenol and 4-chloro-2-nitrophenol are studied. Kinetics analysis shows that the photocatalytic degradation reaction follows a first-order rate equation. Mesoporous 5 Cu/Al(2)O(3)-MCM-41 is found to be an efficient photo-Fenton-like catalyst for the degradation of phenolic compounds. It shows nearly 100% degradation in 45 min at pH 4. The combined effect of small particle size, stabilization of Cu(2+) on the support Al(2)O(3)-MCM-41, ease reducibility of Cu(2+) and visible light activeness are the key factors for quick degradation of phenolic compounds by Cu/Al(2)O(3)-MCM-41.

Cu k-edge studies of the charge carries in Th-doped cuprate system R2-xThxCuO4-δ (R = Nd, Sm and Gd)

International Nuclear Information System (INIS)

Liang, G.; Yi, Y.; Jardim, R.F.; Wang, L.V.

1999-01-01

To further study the charge carrier concentration in electron doped cuprate superconductors, a systematic x-ray absorption near edge structure (XANES) measurement has been carried out on Th-doped superconductor system R 2-x Th x CuO 4-δ (R = Nd, Sm, and Gd). The XANES results show that, similar to the Ce-doped compounds, while the intensity of the Cu 1+ 4p π feature increase with the increase of the Th doping level x, the intensities of the Cu 2+ 4p π and 4p σ features decreases. This clearly indicates that the electrons doped by the Th atoms are injected into the local Cu 3d-orbitals. The normalized Cu 1+ 4p π intensity data show that the Cu 1+ concentration in the Th-doped compound series with different R-elements is linearly proportional to the Th doping-level x. The data suggest that both Ce and Th donate the same fraction of electrons into the Cu sites

Synthesis of double molybdates of copper (1) and trivalent metals, CuR(MoO4)2

International Nuclear Information System (INIS)

Klevtsov, P.V.; Perepelitsa, A.P.; Sinkevich, A.V.; Ishchenko, V.N.; Fomenko, V.V.; Nagornyj, P.G.; AN SSSR, Novosibirsk. Inst. Neorganicheskoj Khimii)

1987-01-01

The method of Cu 2 O solid-phase synthesis was applied to prepare CuR(MoO 4 ) 2 in the vacuum at 480-500 deg C. Cu 2 O, R 2 O 3 and MoO 3 or R 2 '(MoO 4 ) 2 (R'=Ce, Pr, Tb) and MoO 3 were the initial components. The methods of X-ray phase analysis and IR spectroscopy were applied to discover 5 types of compound structures. Among them only CuIn(MoO 4 ) 2 is found crystallized in the known structural type LiFe(WO 4 ) 2 (modification of tungstite structure, (Fe,Mn)WO 4 ). Thermal behaviour of double molybdates is studied thermographically

EXAFS investigations of Cu-Mg-O compound

CERN Document Server

Sidorenko, A F; Babanov, Y A; Naumov, S V; Samokhvalov, A A

2001-01-01

The interest to systems containing copper oxide is connected with the problem of high-temperature superconductivity because of the closeness of its basic physical properties and properties of superconductor mother Cu-compounds. In this work, EXAFS study of the Cu sub 0 sub . sub 2 Mg sub 0 sub . sub 8 O compound is presented. A new iterative algorithm of the solution of ill-posed problem on determining three partial pair correlation functions from one EXAFS-data set near the Cu K-edge is described. The results of X-ray scattering study of a given sample show a presence of a single phase with the MgO structure and a lattice parameter of 4.219 A instead of 4.208 A for pure MgO. From the EXAFS investigations, we find the local distortion of the lattice. We revealed that the short range order differs both from a hypothetical alloy with the MgO structure and from copper oxide.

Barium contributions to the valence electronic structure of YBa2Cu3O7-δ, PrBa2Cu3O7-δ, and other barium-containing compounds

International Nuclear Information System (INIS)

Mueller, D.R.; Wallace, J.S.; Jia, J.J.; O'Brien, W.L.; Dong, Q.; Callcott, T.A.; Miyano, K.E.; Ederer, D.L.

1995-01-01

Monochromatic photon beams were used to excite barium N IV,V soft x-ray emission spectra from YBa 2 Cu 3 O 7-δ , PrBa 2 Cu 3 O 7-δ , BaF 2 , and BaTiO 3 . Near threshold excitation was used to demonstrate that small contributions to the barium N V and N IV emission spectra in the energy region above the 5p→4d core-core transitions do not arise as satellite emission from transitions in multiply excited atoms but rather occur as a result of transitions from the valence states. The emission spectrum of YBa 2 Cu 3 O 7-δ and PrBa 2 Cu 3 O 7-δ reveals a contribution to the electronic density of states at the barium site in the region near the Fermi level. The YBa 2 Cu 3 O 7-δ compound is a superconductor and PrBa 2 Cu 3 O 7-δ is an insulator. It has been proposed that the difference between them is due to mixing of praseodymium and barium among the sites occupied by yttrium and barium, with an accompanying change in electronic structure. However, our measurements indicate that the barium partial density of states for the two compounds are essentially identical

Use of Chitosan-modified Bentonite for Removal of Cu2+, Cl- and 2,4-Dichlorophenoxyacetic Acid (2,4-D from Aqueous Solution

Directory of Open Access Journals (Sweden)

Ba, K.

2014-07-01

Full Text Available Batch experiments were performed to investigate the removal of Cu2+ , Cl- , and 2,4-dichlorophe- noxyacetic acid (2,4-D from aqueous solution using chitosan-modified bentonite. When the chi-tosan was loaded on the bentonite, the inter-layer space of the montmorillonite increased and the adsorption efficiency enhanced, as chitosan contains large numbers of -NH2 and -OH functional groups that could serve as coordination sites to bind heavy metals. In this study, the bentonite that was prepared through three procedures: Na2CO3 treatment, thermal treatment and compound treatment, was modified by chitosan. Experimental results demonstrated that the average removal rates of Cu2+ , Cl-, and 2,4-D effectively were 94.87 %, 86.19 % and 91.06 %, respectively.

Heterospin systems constructed from [Cu2Ln]3+ and [Ni(mnt)2]1-,2- Tectons: First 3p-3d-4f complexes (mnt = maleonitriledithiolato).

Science.gov (United States)

Madalan, Augustin M; Avarvari, Narcis; Fourmigué, Marc; Clérac, Rodolphe; Chibotaru, Liviu F; Clima, Sergiu; Andruh, Marius

2008-02-04

New heterospin complexes have been obtained by combining the binuclear complexes [{Cu(H(2)O)L(1)}Ln(O(2)NO)(3)] or [{CuL(2)}Ln(O(2)NO)(3)] (L(1) = N,N'-propylene-di(3-methoxysalicylideneiminato); L(2) = N,N'-ethylene-di(3-methoxysalicylideneiminato); Ln = Gd(3+), Sm(3+), Tb(3+)), with the mononuclear [CuL(1)(2)] and the nickel dithiolene complexes [Ni(mnt)(2)](q)- (q = 1, 2; mnt = maleonitriledithiolate), as follows: (1)infinity[{CuL(1)}(2)Ln(O(2)NO){Ni(mnt)(2)}].Solv.CH(3)CN (Ln = Gd(3+), Solv = CH(3)OH (1), Ln = Sm(3+), Solv = CH(3)CN (2)) and [{(CH(3)OH)CuL(2)}(2)Sm(O(2)NO)][Ni(mnt)(2)] (3) with [Ni(mnt)2]2-, [{(CH(3)CN)CuL(1)}(2)Ln(H(2)O)][Ni(mnt)(2)]3.2CH(3)CN (Ln = Gd(3+) (4), Sm(3+) (5), Tb(3+) (6)), and [{(CH(3)OH)CuL(2)}{CuL(2)}Gd(O(2)NO){Ni(mnt)(2)}][Ni(mnt)(2)].CH(2)Cl(2) (7) with [Ni(mnt))(2]*-. Trinuclear, almost linear, [CuLnCu] motifs are found in all the compounds. In the isostructural 1 and 2, two trans cyano groups from a [Ni(mnt)2]2- unit bridge two trimetallic nodes through axial coordination to the Cu centers, thus leading to the establishment of infinite chains. 3 is an ionic compound, containing discrete [{(CH(3)OH)CuL(2)}(2)Sm(O(2)NO)](2+) cations and [Ni(mnt)(2)](2-) anions. Within the series 4-6, layers of discrete [CuLnCu](3+) motifs alternate with stacks of interacting [Ni(mnt)(2)](*-) radical anions, for which two overlap modes, providing two different types of stacks, can be disclosed. The strength of the intermolecular interactions between the open-shell species is estimated through extended Hückel calculations. In compound 7, [Ni(mnt)(2)](*-) radical anions coordinate group one of the Cu centers of a trinuclear [Cu(2)Gd] motif through a CN, while discrete [Ni(mnt)(2)](*-) units are also present, overlapping in between, but also with the coordinated ones. Furthermore, the [Cu(2)Gd] moieties dimerize each other upon linkage by two nitrato groups, both acting as chelate toward the gadolinium ion from one unit and monodentate toward a

Effect of cupric salts (Cu (NO{sub 3}){sub 2}, CuSO4{sub ,} Cu(CH{sub 3}COO){sub 2}) on Cu{sub 2}(OH)PO{sub 4} morphology for photocatalytic degradation of 2,4-dichlorophenol under near-infrared light irradiation

Energy Technology Data Exchange (ETDEWEB)

Hu, Chao; Li, Pei; Zhang, Wei; Che, Yanhao; Sun, Yaxin; Chi, Fangli; Ran, Songlin; Liu, Xianguo; Lv, Yaohui, E-mail: yaohui2015@163.com [School of Materials Science and Engineering, Anhui Key Laboratory of Metal Materials and Processing, Anhui University of Technology (China)

2017-03-15

Cu{sub 2}(OH)PO{sub 4} microstructures were synthesized by the hydrothermal method using three different types cupric salts (Cu (NO{sub 3}){sub 2}, CuSO{sub 4}, Cu(CH{sub 3}COO){sub 2}) as raw materials. The X-ray diffraction (XRD), scanning electron microscopy (SEM) and UV-visible-NIR absorption spectra were used to characterize the as-obtained products. The different anions (SO{sub 4}{sup 2-}, CH{sub 3}COO-, NO{sub 3-}) have different shapes and polarities, which can generate different interactions in reaction bath, induced the difference of structure and morphology of the prepared Cu{sub 2}(OH)PO{sub 4}. The Cu{sub 2}(OH)PO{sub 4} microstructures prepared form Cu(NO{sub 3}){sub 2} ·3H{sub 2}O showed the best photocatalytic activity induced by near-infrared light to degrade 2,4-dichlorophenol (2,4-DCP) solution. Our work suggests that the active morphological surfaces as well as different coordination environments for the metal ions has an important influence on the photocatalytic performance of Cu{sub 2}(OH)PO{sub 4} microstructure. (author)

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

CERN Document Server

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

2003-01-01

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

Computational insight on the structural, mechanical and thermal properties of Cu2CdSnSe4 and Cu2HgSnSe4 adamantine materials

Directory of Open Access Journals (Sweden)

S. Bensalem

2016-12-01

Full Text Available Through first-principles calculation based on the density functional theory (DFT within the pseudo potential-plane wave (PP-PW approach, we studied the structural, mechanical and thermal properties of Cu2CdSnSe4 and Cu2HgSnSe4 adamantine materials. The calculated lattice parameters are in good agreement with experimental and theoretical reported data. The elastic constants are calculated for both compounds using the static finite strain scheme. The hydrostatic pressure action on the elastic constants predicts that both materials are mechanically stable up to 10 GPa. The polycrystalline mechanical parameters, i.e., the anisotropy factor (A, bulk modulus (B, shear modulus (G, Young's modulus (E, Lame's coefficient (λ and Poisson's ratio (ν have been estimated from the calculated single crystal elastic constants. The analysis of B/G ratio shows that the two studied compounds behave as ductile. Based on the calculated mechanical parameters, the Debye temperature and the thermal conductivity have been probed. In the framework of the quasi-harmonic approximation, the temperature dependence of the lattice heat capacity of both crystals has been investigated.

Cu2+-labeled dansyl compounds as fluorescent and PET probes for imaging apoptosis.

Science.gov (United States)

Han, Junyan; Wang, Xukui; Yu, MeiXiang

2016-11-15

Compound DNSTT-Cu 2+ , a novel chelate of Cu 2+ with DOTA conjugated to a fluorescent dansyl fragment, is developed for imaging cell apoptosis. Apoptotic U-87MG cells could be selectively visualized by the fluorescence of DNSTT-Cu 2+ from cytoplasm of cells, confirmed by the fluorescence of apoptosis cells co-labeled with Alexa Fluor 568-labeled annexin V, a conventional probe for selectively labeling membranes of apoptosis cells. A radioactive 64 Cu 2 + analog, DNSTT- 64 Cu 2+ , was easily synthesized, providing a potential PET probe for imaging apoptosis in vivo. Copyright © 2016 Elsevier Ltd. All rights reserved.

Fingerprints of field-induced Berezinskii–Kosterlitz–Thouless transition in quasi-two-dimensional S=1/2 Heisenberg magnets Cu(en)(H{sub 2}O){sub 2}SO{sub 4} and Cu(tn)Cl{sub 2}

Energy Technology Data Exchange (ETDEWEB)

Baranová, Lucia [Civil Engineering Faculty, Department of Applied Mathematics, Technical University of Košice, Vysokoškolská 4 SK-042 00, Košice (Slovakia); Orendáčová, Alžbeta, E-mail: alzbeta.orendacova@upjs.sk [Center of Low Temperature Physics, Faculty of Science, P. J. Šafárik University, Park Angelinum 9 SK-041 54, Košice (Slovakia); Čižmár, Erik [Center of Low Temperature Physics, Faculty of Science, P. J. Šafárik University, Park Angelinum 9 SK-041 54, Košice (Slovakia); Tarasenko, Róbert; Tkáč, Vladimír [Center of Low Temperature Physics, Faculty of Science, P. J. Šafárik University, Park Angelinum 9 SK-041 54, Košice (Slovakia); Charles University, Faculty of Mathematics and Physics, Ke Karlovu 5 12116, Prague (Czech Republic); Orendáč, Martin; Feher, Alexander [Center of Low Temperature Physics, Faculty of Science, P. J. Šafárik University, Park Angelinum 9 SK-041 54, Košice (Slovakia)

2016-04-15

Organo-metallic compounds Cu(en)(H{sub 2}O){sub 2}SO{sub 4} (en=C{sub 2}H{sub 8}N{sub 2}) and Cu(tn)Cl{sub 2} (tn=C{sub 3}H{sub 10}N{sub 2}) representing S=1/2 quasi-two-dimensional Heisenberg antiferromagnets with an effective intra-layer exchange coupling J/k{sub B}≈3 K, have been examined by specific heat measurements at temperatures down to nominally 50 mK and magnetic fields up to 14 T. A comparative analysis of magnetic specific heat in zero magnetic field revealed nearly identical contribution of short-range magnetic correlations and significant differences were observed at lowest temperatures. A phase transition to long-range order was observed in Cu(en)(H{sub 2}O){sub 2}SO{sub 4} at T{sub C}=0.9 K while hidden in Cu(tn)Cl{sub 2}. A response of both compounds to the application of magnetic field has rather universal features characteristic for a field-induced Berezinskii–Kosterlitz–Thouless transition theoretically predicted for ideal two-dimensional magnets. - Highlights: • Magnetic specific heat of Cu(en)(H{sub 2}O){sub 2}SO{sub 4} (1) and Cu(tn)Cl{sub 2} (2) was analysed. • In zero magnetic field, (1) and (2) behave as quasi-two-dimensional magnets. • We observed universal thermodynamic response of (1) and (2) to applied field. • Features of field-induced Berezinskii–Kosterlitz–Thouless transition were detected.

Chemical bond properties and Mossbauer spectroscopy in (La1-xMx)2CuO4 (M=Ba, Sr)

Institute of Scientific and Technical Information of China (English)

无

2002-01-01

By using the average band-gap model, the chemical bond properties of (La1-x Mx)2CuO4(M=Ba, Sr) were calculated . The calculated covalencies for Cu(O and La(O bond in the compounds are 0.3 and 0.03 respectively. M?ssbauer isomer shifts of 57Fe doped in La2CuO4 and 119Sn doped in La2CuO4 were calculated by using the chemical surrounding factor defined by covalency and electronic polarizability. Four valence state tin and three valence iron sites were identified in 57Fe and 119Sn doped La2CuO4.

Bonding in [CuNRR′]4 type clusters

Institute of Scientific and Technical Information of China (English)

WANG Bingwu; XU Guangxian; CHEN Zhida

2004-01-01

Many polynuclear Cu(I) compounds have been synthesized, but the problem whether there is direct or no direct Cu-Cu bonding in these compounds is not clear. The electronic structure of [CuNRR′]4 type clusters was investigated by using density functional methods. The results of geometrical optimization are in good agreement with experiment, and the localization of MO's shows that there are four Cu-Cu ( bonds to form the square Cu4 ring in addition to the four bridging Cu-N-Cu bonds. A concept of the covalence of molecular fragments is proposed to describe the bonding in these clusters.

Room temperature transport properties of new BiSrCaCuO compounds; Proprietes de transport a la temperature ambiante de nouveaux composes BiSrCaCuO

Energy Technology Data Exchange (ETDEWEB)

Lagues, M.; Partiot, C.; Mairet, V.; Hatterer, C.; Xu, X.Z.; Deville Cavellin, C. [Laboratoire Surface et Supraconducteurs, Ecole Superieure de Physique et de Chimie Industrielle, CNRS UPR5, Universite Paris, 75 - Paris (France); Beuran, C.; Eustache, B.; Moussy, J.B. [Wintici SA, 94 - Vincennes (France)

1997-05-01

New compounds belonging to the BiSrCaCuO cuprate family have been synthesized by sequentially imposed layer epitaxy. The Cu/Ca ratio in these compounds is typically twice the value for conventional Bi{sub 2}Sr{sub 2}Ca{sub n-1}Cu{sub n+4}. A second characteristic of the new compounds is a Bi deficiency relative to conventional BSCCO. The room temperature electrical resistivity of these compounds reaches extremely low values, orders of magnitude below that of copper. Strongly non-linear I(V) characteristics of various forms are observed; Typical examples are describes where the voltage dependence at the onset of measurable dissipation is either exponential or parabolic as a function of current intensity. Examples are also presented I(V) exhibits and hysteric behavior. (authors). 51 refs.

Magnetic Study of the Novel Polynuclear Compound [Cu(II)(6-Mercaptopurinolate 2-)] n

Science.gov (United States)

Acevedo-Chávez, Rodolfo; Costas, María. Eugenia; Escudero, Roberto

1997-08-01

Chemical reactions between Cu(II) and 6-mercaptopurine, both in aqueous and in methanolic media, yield the novel amorphous polynuclear compound [Cu(II)(6-mercaptopurinolate)2-]n, which is also obtained from diverse Cu(II)-heterocyclic ligand competitive reactions. The kinetic and thermodynamic stabilities associated with the formation of this compound are inferred as remarkable. The spectroscopic data let us suggest the involvement of the exocyclic S(6) donor site and the N atoms in the imidazolic moiety of the deprotonated heterocyclic ligand in the coordination to Cu(II) atoms, forming a distorted bidimensional metallic network. The magnetic studies show the existence of very weak antiferromagnetic coupling in the solid sample. This system represents the first example of a 1 : 1 metal : 6-mercaptopurinolate2-system with ad-type open shell metallic center. The magnetic study carried out also represents the first example of magnetic characterization for this type of polynuclear Cu(II) systems with the dianionic 6-mercaptopurine ligand.

Diamagnetism in spinel compound CuIr2S4

International Nuclear Information System (INIS)

Yagasaki, K.; Nakama, T.

2007-01-01

The diamagnetic susceptibility in CuIr 2 S 4 is independent of temperature up to just below metal-insulator transition temperature. If activation of electrons to higher levels occurs with breaking dimer pairs, the residual electrons at the dimer position and the activated electrons to the anti-bonding orbital make localized free spins giving a Langevin paramagnetism. Assuming no magnetic interaction between the localized free spins, the susceptibility is calculated using the energy gap obtained from the conductivity assumed to be a conventional semiconductor. The calculated results cannot explain the temperature-independent diamagnetism. The real energy gap is too large for thermal electron activation, however, conduction is induced thermally over several orders of magnitude within insulating phase. From the above results, we claimed new conduction mechanism named traveling dimer conduction: dimer shifts its position by electron hopping to neighbor position without electron activation over the energy gap

A Novel Ternary CoFe2O4/CuO/CoFe2O4 as a Giant Magnetoresistance Sensor

Directory of Open Access Journals (Sweden)

Ramli

2016-12-01

Full Text Available This paper reports the results of a study relating to the synthesis of a novel ternary CoFe2O4/CuO/CoFe2O4 thin film as a giant magnetoresistance (GMR sensor. The CoFe2O4/CuO/CoFe2O4 thin film was prepared onto silicon substrate via DC magnetron sputtering with the targets facing each other. X-ray diffraction was used to determine the structure of the thin film and a 4-point method was used to measure the MR ratio. The GMR ratio is highly dependent on the ferrimagnetic (CoFe2O4 and nonmagnetic (CuO layer thickness. The maximum GMR ratio at room temperature obtained in the CoFe2O4/CuO/CoFe2O4 thin film was 70% when the CoFe2O4 and the CuO layer had a thickness of 62.5 nm and 14.4 nm respectively.

Synthesis of the compound tetrakis (2- methoxy isobutyl isonitrile) copper (I) tetrafluoroborate -(Cu[MIBI]4BF4): substance used in the production of the radiopharmaceutical sestamibi 99m Tc

International Nuclear Information System (INIS)

Silva, Katia Suzi da Silveira

2005-01-01

The radiopharmaceutical SESTAMIBI- 99m Tc presents interest and application in the clinical routine in Nuclear Medicine, especially for evaluation of the myocardium function and in the diagnosis of some tumors types, and the Center of Radiopharmacy of the IPEN has interest in the development of this radiopharmaceutical for attendance of the nuclear medicine class necessities. In this work it was demonstrated the synthesis and characterization of the active compound tetrakis (2- methoxy isobutyl isonitrile) copper (I) tetrafluoroborate - Cu[MIBI] 4 BF 4 - to be used in the preparation of lyophilized reagents for labeling with technetium- 99m as well as labeling studies and biological distribution. The synthesis of the reagent Cu[MIBI] 4 BF 4 was carried out in accordance with previously described procedures, in 5 steps and the compounds were characterized for infra-red, magnetic nuclear resonance, melting point and thin layer chromatography. The characterization of the chelate of MIBI -Cu[MIBI] 4 BF 4 - was carried out using high performance liquid chromatography, compared with a standard sample of the product and presented similar results, as described in literature. The lyophilized reagent was prepared and labeled with technetium- 99m , showing high radiochemical purity, higher than 97%, with high stability. Biological distribution in different animals showed good uptake in the heart, in time compatible with the acquisition of scintigraphy images, demonstrating the applicability of the reagent synthesized in the attainment of cardiac scintigraphy images. (author)

Galvanomagnetic properties of atomically disordered compounds YBa2Cu3O7

International Nuclear Information System (INIS)

Kar'kin, A.E.; Goshchitskij, B.N.

2001-01-01

To clarify the peculiarities of the metal-dielectric transition (MDT) in the HTSC type compounds one investigated into the galvanomagnetic properties of YBa 2 Cu 3 O 7 polycrystalline specimens irradiated by fast neutrons under 80 K temperature with F = 2x10 19 cm -2 fluence and subsequent to their exposure to the isochronal annealings within 150-390 K temperature range. It was determined that temperature dependences of R H Hall coefficient and of MR magnetic resistances of YBa 2 Cu 3 O 7 polycrystalline compounds disordered by fast neutrons retained the anomalous properties peculiar to the HTSC type disordered compounds in spite of the fact that conductivity was not a metallic one. This behavior is explained by the fact that in the disordered compounds there are two co-existing electron phases with conductivity as to the localized and the metallic states. Concentration of metallic phase is lower than threshold of passing, that is why, conductivity of this system is of dielectric type while R H and MR have temperature dependences similar to metallic phase that are renormalized by magnitude [ru

Antiferromagnetic order in the ladder compound SrCu{sub 2}O{sub 3}: Cu-NMR/NQR measurements

Energy Technology Data Exchange (ETDEWEB)

Ohsugi, S.; Kitaoka, Y.; Azuma, M.; Fujishiro, Y.; Takano, M.

1999-12-01

The authors carried out the extensive Cu-nuclear magnetic and quadrupole resonance (NMR/NQR) experiments on the Zn(Ni)-doped ladder compound SrCu{sub 2}O{sub 3} (Sr123), Sr(Cu{sub 1{minus}x}M{sub x}){sub 2}O{sub 3} (M = Zn and Ni) with x {le} 0.02 and the La-doped Sr123, Sr{sub 1{minus}x}La{sub x}Cu{sub 2}O{sub 3} with {alpha} {le} 0.03. A spin-correlation length {xi}{sub s}/a (a: the lattice spacing between the Cu sites along the leg) of nonmagnetic impurity-induced staggered polarization (IISP) estimated from a quasi-one-dimensional (Q1D) IISP along the two legs in the 0.1--2% Zn-doped Sr123 was found to be independent of temperature (T) and scaled to an mean impurity distance D{sub AV} with the relation of {xi}{sub s}/a = 2.5 + D{sub AV}. The {xi}{sub s}/a's are much longer in x = 0.001 ({xi}{sub s}/a {approximately} 50) and 0.005 ({xi}{sub s}/a {approximately} 12) than an instantaneous spin-correlation length {xi}{sub 0}/a {approximately} 3--8 in Sr123. The formula of Neel T, T{sub N} (WC-Q1D) = J exp({minus}D{sub AV}/({xi}{sub s}/a)) (J = 2,000 K) based on the weakly interladder-coupled (WC) Q1D model explains the experimental T{sub N} values quantitatively.

Electronic structures of PrBa2Cu3O7, Pr2Ba4Cu7O15-y(y=0,1), and PrBa2Cu4O8 based on LSDA+U method

International Nuclear Information System (INIS)

Tavana, A.; Shirazi, M.; Akhavan, M.

2009-01-01

The electronic structures of PrBa 2 Cu 3 O 7 (Pr123), Pr 2 Ba 4 Cu 7 O 15-y (Pr247), and PrBa 2 Cu 4 O 8 (Pr124) cuprates have been obtained using density-functional theory in the local spin density approximation plus onsite Coulomb interaction (LSDA+U). Onsite Hubbard correlation, U, has been considered for Pr-f and Cu-d orbitals and the effects of considering these correlation corrections on the Pr-O hybridizations have been inspected. Results imply that the Pr ionization state in Pr123 system is constituted from two different configurations, and the energy of the f states in these two configurations has an important role in superconductivity properties of the system. Our calculations also show that in both Pr124 and Pr247 systems, suppression of superconductivity is weaker than that in the Pr123 system. This occurs due to the weaker Pr-O bond in both Pr124 and Pr247 systems. The role of the double chain and single chain on the conduction properties of these compounds has been investigated. We have also studied the effect of oxygen deficiency in Pr247 system, which seems to revive superconductivity in this system. Investigating the hole carriers in the CuO 2 plane shows a correlation between superconductivity suppression and hole decrement in the planes. (Abstract Copyright [2009], Wiley Periodicals, Inc.)

Low-temperature structural phase transition in synthetic libethenite Cu2PO4OH

International Nuclear Information System (INIS)

Belik, Alexei A.; Naumov, Pance; Kim, Jungeun; Tsuda, Shunsuke

2011-01-01

Low-temperature structural properties of the synthetic mineral libethenite Cu 2 PO 4 OH were investigated by single-crystal X-ray diffraction, synchrotron X-ray powder diffraction, specific heat measurements, and Raman spectroscopy. A second-order structural phase transition from the Pnnm symmetry (a=8.0553(8) A, b=8.3750(9) A, c=5.8818(6) A at 180 K) to the P2 1 /n symmetry (a=8.0545(8) A, b=8.3622(9) A, c=5.8755(6) A, β=90.0012(15) at 120 K) was found at 160 K during cooling. At 120 K, the monoclinic angle is 90.0012(15) from single crystal X-ray data vs 90.083(1) from powder X-ray diffraction data. The P2 1 /n-to-Pnnm transition may be a general feature of the adamite-type compounds, M 2 XO 4 OH. - Graphical Abstract: Fragments of experimental synchrotron X-ray powder diffraction patterns of Cu 2 PO 4 OH between 100 and 280 K. Arrows show additional reflections that appear below 160 K in the monoclinic P2 1 /n phase. Highlights: → A low-temperature phase transition was found in the mineral libethenite Cu 2 PO 4 OH. → No magnetic anomalies and weak specific heat anomalies are detected. → Phase transition is of the second order. → Libethenite may exemplify a general feature of the adamite-type compounds.

X-ray attenuation coefficient measurements for photon energies 4.508-13.375 keV in Cu, Cr and their compounds and the validity of the mixture rule

International Nuclear Information System (INIS)

Turgut, Ue.; Simsek, Oe.; Bueyuekkasap, E.; Ertugrul, M.

2004-01-01

To investigate the validity of the mixture rule which is used to compute the mass attenuation coefficients in compounds, the total mass attenuation coefficients for Cu, Cr elements and Cu 2 O, CuC 2 O 4 , CuCl 2 ·2H 2 O, Cu(C 2 H 3 O 2 ) 2 ·H 2 O, Cr 2 O 3 , Cr(NO 3 ) 3 , Cr 2 (SO 4 ) 3 ·H 2 O, Cr 3 (CH 3 CO 7 )(OH) 2 compounds were measured at photon energies between 4.508 and 13.375 keV by using the secondary excitation method. Ti, Mn, Fe, Ni, Zn, Ge, As, Rb elements were used as secondary exciters. 59.5 keV gamma rays emitted from an 241 Am annular source were used to excite the secondary exciters and Kα (K-L 3 , L 2 ) rays emitted from the secondary exciter were counted by a Si(Li) detector with a resolution of 160 eV at 5.9 keV. Our measurements indicate that the mixture rule is not a suitable method for the computation of mass attenuation coefficients of compounds especially at an energy that is near the absorption edge. Obtained values were compared with theoretical values

Electronic structures of PrBa2Cu3O7 and PrBa2Cu4O8 systems based on LSDA+U approach

International Nuclear Information System (INIS)

Shirazi, M.; Tavana, A.; Akhavan, M.

2007-01-01

Full text: The electronic structures of PrBa 2 Cu 3 O 7 (Pr123) and PrBa 2 Cu 4 O 8 (Pr124) have been obtained by means of the density functional theory in the local spin density approximation plus on-site Coulomb interaction. The correlation correction has been applied to the Cu 3d and Pr 4f states. Calculations show that the localized Pr-O bands form near the Fermi surface and do not cross the Fermi level. Comparison of the hole absorbing ability of pfy and the pdy states shows that pfy state has dominant role in grabbing holes from the system and causes Pr124 to be non-superconducting like Pr123. We suggest that hybridization of Pr and O atoms in Pr124 system is weaker than Pr123 compound and this may be the reason for the higher critical doping of Pr by which the superconductivity is completely suppressed. Displacement of the conduction bands at the Fermi level is the criterion of Cu (3dx2-y2) character, and when Cu (3dx2-y2) character is stronger in a band, the band displaces more intensively under applying the correction Ucu. We estimate the hole-concentration from this displacement, and good agreement with experiment is seen. The displacement of the CuO 2 plane bands in the minority and majority spin channels in Pr124 is less than that in Pr123. Displacement of the double chain bands in Pr124 is higher than the single chain bands in Pr123. This feature is related to a stronger Cu (3dx2-y2) character in the double chain. So, the spin and conduction features of the Pr124 double chains are stronger than Pr123 single chain, which is the origin of metallic behavior of Pr124 at low temperatures.(authors)

Electronic structures of PrBa2Cu3O7 and PrBa2Cu4O8 systems based on LSDA+U approach

International Nuclear Information System (INIS)

Shirazi, M.; Tavana, A.; Akhavan, M.

2007-01-01

Full text: The electronic structures of PrBa 2 Cu 3 O 7 (Pr123) and PrBa 2 Cu 4 O 8 (Pr124) have been obtained by means of the density functional theory in the local spin density approximation plus on-site Coulomb interaction. The correlation correction has been applied to the Cu 3d and Pr 4f states. Calculations show that the localized Pr-O bands form near the Fermi surface and do not cross the Fermi level. Comparison of the hole absorbing ability of pfy and the pdy states shows that pfy state has dominant role in grabbing holes from the system and causes Pr124 to be non-superconducting like Pr123. We suggest that hybridization of Pr and O atoms in Pr124 system is weaker than Pr123 compound and this may be the reason for the higher critical doping of Pr by which the superconductivity is completely suppressed. Displacement of the conduction bands at the Fermi level is the criterion of Cu (3dx2-y2) character, and when Cu (3dx2-y2) character is stronger in a band, the band displaces more intensively under applying the correction Ucu. We estimate the hole-concentration from this displacement, and good agreement with experiment is seen. The displacement of the CuO 2 plane bands in the minority and majority spin channels in Pr124 is less than that in Pr123. Displacement of the double chain bands in Pr124 is higher than the single chain bands in Pr123. This feature is related to a stronger Cu (3dx2-y2) character in the double chain. So, the spin and conduction features of the Pr124 double chains are stronger than Pr123 single chain, which is the origin of metallic behavior of Pr124 at low temperatures. (authors)

ZrCu2P2 and HfCu2P2 phosphides and their crystal structure

International Nuclear Information System (INIS)

Lomnitskaya, Ya.F.

1986-01-01

Isostructural ZrCu 2 P 2 and HfCu 2 P 2 compounds are prepared for the first time. X-ray diffraction analysis (of powder, DRON-2.0 diffractometer, FeKsub(α) radiation) was used to study crystal structure of HfCu 2 P 2 phosphide belonging to the CaAl 2 Si 2 structural type (sp. group P anti 3 m 1, R=0.095). Lattice parameters the compounds are as follows: for ZrCu 2 P 2 a=0.3810(1), c=0.6184(5); for HfCu 2 P 2 a=0.3799(1), c=0.6160(2) (nm). Atomic parameters in the HfCu 2 P 2 structure and interatomic distances are determined

Synthesis and vibrational spectra of cooper(II) and erbium(III) complexes with 2-diazo[2'-(oxymethyldiphenylphosphinyl)phenyl]-4-tert-butylphenol (HL) - [CuL2]·2H2O and Er(NO3)3·2HL·2H2O. Crystal structure of [CuL2]·2H2O

International Nuclear Information System (INIS)

Tsivadze, A.Yu.; Minacheva, L.Kh.; Ivanova, I.S.; Pyatova, E.N.; Sergienko, V.S.; Baulin, V.E.

2008-01-01

Paper describes synthesis of CuL 2 ·2H 2 O (I) complex cupric salt and of Er(NO 3 ) 3 ·2HL·2H 2 O (II) erbium nitrate complex (HL=2-diazo-[2'(oxymethyl-diphenyl-phosphinyl)phenyl]-4-tert-butylphenol). One interprets the fundamental frequencies within the IR-spectra of (I) and (II) compounds. One has performed X-ray diffraction analysis of I compound. The crystals are monoclinic ones, a=15.157(3), b=17.080(2), c=22.451(9) A, β=106.09(3) Deg, V=5584(3) A 3 , Z=4, C2/c sp.gr., R=0.0546 as to 1152 reflections with I>2σ(I). The copper atom coordination polyhedron (C 2 symmetry) may be described as a symmetrically-prolonged square bipyramid (4+2). Cu polyhedron central square is formed by substituted phenol oxygen atom and by one of diazo-group nitrogen atoms of either of two deprotonated ligands, namely: L - (Cu-N 1.969(6), Cu-O 1.899(5) A). The angles between lying opposite O and N atoms constitute 157.6 Deg, while the rest equatorial angles range within 90.6 Deg-95.9 Deg. The axial positions are occupied by O(2) and O(2A) anisole atoms (Cu-O 2.737(6) A, O(2)Cu(1)O(2A) angle constitutes 132.3 Deg). Within crystal I the complex molecules and the crystallization molecules of water are combined by by the hydrogen bond system. According to the IR-spectra data, within complex II in contrast to compound I erbium atom coordination by HL ligand involves oxygen phosphoryl atom [ru

Interaction of copper(II) halides with 4-(piperidyl-1)-2-phenylpyrido[2,3-a]anthraquinone-7,12 (L) in acidic media: Crystal structure and spectral characteristics of (HL)2[Cu2Cl6] and (HL)[CuBr2

International Nuclear Information System (INIS)

Kovalchukova, O. V.; Stash, A. I.; Strashnova, S. B.; Belsky, V. K.; Tung, Tran Than; Zaitsev, B. E.

2008-01-01

4-(Piperidyl-1)-2-phenylpyrido[2,3-a]anthraquinonium-7,12 hexachlorodicuprate(II) and 4-(piperidyl-1)-2-phenylpyrido[2,3-a]anthraquinonium-7,12 dibromocuprate(I) are isolated in the crystalline state and investigated using X-ray diffraction. It is established that the Cu(II) cation is reduced to the Cu(I) cation during the synthesis of anionic bromocuprate complexes in the presence of hydrobromic acid. The spectral characteristics of the prepared compounds are discussed.

Kinetic and mechanism formation reaction of complex compound Cu with di-n-buthildithiocarbamate (dbdtc) ligand

Science.gov (United States)

Haryani, S.; Kurniawan, C.; Kasmui

2018-04-01

Synthesis of complex compound is one field of research which intensively studied. Metal-dithiocarbamate complexes find wide-ranging applications in nanomaterial and metal separation science, and have potential use as chemotherapeutic, pesticides, and as additives to lubricants. However, the information about is reaction kinetic and mechanism are very much lacking. The research and analyzes results show that reaction synthesis ligand DBDTC and complex compounds Cu-DBDTC. Optimum reaction condition of formation of complex compounds Cu with DBDTC at pH=3, [DBDTC] = 4.10-3 M, and the time of reaction 5 minutes. Based the analysis varian reaction of complex compounds at pH 3 and 4, diffrence significance at the other pH: 5; 5,5; 6; 6,5 ; 7; and 8. The various of mole with reactants comosition difference sigbificance, those the time reaction for 5 and 6 minutes diffrence by significance with the other time, it is 3,4,8, and 10 minutes. The great product to at condition pH 6, the time optimum at 5 minutes and molar ratio of logam: ligand = 1:2. The reaction kinetic equation of complex compound Cu with chelathing ligand DBDTC is V=0.917106 [Cu2+]0.87921 [DBDTC]2.03021. Based on the kinetic data, and formed complex compounds estimation, the mechanism explaining by 2 stages. In the first stage formation of [Cu(DBDTC)], and then [Cu(DBDTC)2] with the last structure geomethry planar rectangle. The result of this research will be more useful if an effort is being done in reaction mechanism by chemical computation method for obtain intermediate, and for constant “k” in same stage, k1.k2. and compound complex constanta (β).

Structural and antimicrobial studies of coordination compounds of VO(II, Co(II, Ni(II and Cu(II with some Schiff bases involving 2-amino-4-chlorophenol

Directory of Open Access Journals (Sweden)

A. P. MISHRA

2009-05-01

Full Text Available Complexes of tailor-made ligands with life essential metal ions may be an emerging area to answer the problem of multi-drug resistance (MDR. The coordination complexes of VO(II, Co(II, Ni(II and Cu(II with the Schiff bases derived from 2-hydroxyacetophenone/2-chlorobenzaldehyde with 2-ami¬no-4-chlorophenol were synthesized and characterized by elemental analysis, molar conductance, electronic spectra, FT-IR, ESR, FAB mass, thermal and magnetic susceptibility measurements. The FAB mass and thermal data show degradation of the complexes. The ligand A (2-hydroxyacetophenone-2amino-4-chlorophenol behaved as tridentate and ligand B (2-chlorobenzylidene-2-amino-4-chlorophenol as bidentate, coordinating through O and N donors. The complexes [VO(A(H2O]×xH2O, [M(A(H2On]×xH2O for Co and Ni, [Cu(A(H2O] and [VO(B2]×xH2O, [M(B2(H2On] for Co and Cu and [Ni(B2] exhibited coordination numbers 4, 5 or 6. X-ray powder diffraction data (a = 11.00417 Å, b = 11.706081 Å and c = 54.46780 Å showed that [Cu(CACP2(H2O2], complex 8, crystallized in the orthorhombic system. The in vitro biological screening effects of the investigated compounds were tested against the bacteria Escherichia coli, Staphylococcus aureus and Streptococcus fecalis and the fungi Aspergillus niger, Trichoderma polysporum and Candida albicans by the serial dilution method. A comparative study of the MIC values of the Schiff base and their [M(B2(H2O2] complexes (Co(II, complex 6 and Cu(II, complex 8, indicated that the metal complexes exhibited a higher or lower antimicrobial activity than 2-chlorobenzylidene-2-amino-4-chlorophenol as the free ligand (B.

Cu4Pr6(MoO4)11-Pr2(MoO4)3 system

International Nuclear Information System (INIS)

Arzumanyan, G.A.

1982-01-01

Existence boundaries and Dalton compositions (CuPr(MoO 4 ) 2 , CuPr 3 (MoO 4 ) 5 ) of solid solutions that in the mojority are of shcheelite dsitored structure have been determined in the Cu 4 Pr 6 (MoO 4 ) 11 -Pr 2 (MoO 4 ) 3 system. It has been revealed that regions of homogeneity near the CuPr(MoO 4 ) 2 composition have a horseshoeshaped profile

Novel chemical route for deposition of Cu{sub 2}ZnSnS{sub 4} photovoltaic absorbers

Energy Technology Data Exchange (ETDEWEB)

Gordillo, Gerardo; Becerra, Raul A.; Calderón, Clara L., E-mail: ggordillog@unal.edu.co [Universidad Nacional de Colombia, Bogota (Colombia)

2018-05-01

This work reports results of a study carried out to optimize the preparation conditions of Cu{sub 2}ZnSnS{sub 4} (CZTS) thin films grown by sequential deposition of Cu{sub 2}SnS{sub 3} (CTS) and ZnS layers, where the Cu{sub 2}SnS{sub 3} compound was grown using a novel procedure consisting of simultaneous precipitation of Cu{sub 2}S and SnS{sub 2} performed by diffusion membrane assisted chemical bath deposition (CBD) technique. The precipitation across the diffusion membranes allows achieving moderate control of release of metal ions into the work solution favoring the heterogeneous growth mainly through an ion-ion mechanism. Through a parameters study, conditions were found to grow Cu{sub 2}SnS{sub 3} thin films which were used as precursors for the formation of Cu{sub 2}ZnSnS{sub 4} films. The formation of CZTS thin films grown in the Cu{sub 2}ZnSnS{sub 4} phase was verified through measurements of X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS) and Raman spectroscopy. Solar cells with efficiencies of 4.9% were obtained using CZTS films prepared by membrane assisted CBD technique as absorber layer. (author)

Some crystal chemistry of (Ln,Ce)2CuO4-δ superconductors

International Nuclear Information System (INIS)

Goodman, P.; Keating, A.; Myhra, S.; White, T.J.

1989-01-01

Compounds of the form (Ln, Sr, Ce) 2 CuO 4-δ (Ln = rare earth element) crystallise as the Nd 2 CuO 4 structure type, K 2 NiF 4 structure type or perfectly and imperfectly ordered intergrowths of these parent structures. These structurally similar phases exhibit superconductivity in which the charge carriers are holes (in Sr-doped material) or electrons (in Ce doped material). In this study, X-ray Photoelectron Spectroscopy (XPS) and High Resolution Electron Microscopy (HREM) were used to investigate the charge balancing mechanisms operating in each superconducting regime and the structural changes accompanying compositional variation. It was found that under slightly reducing conditions charge coupled cation substitutions predominate, whilst at low pO 2 ( -5 atm) perfectly ordered oxygen superlattices form. The structural and electronic changes which accompany deoxygenation were observed in situ during XPS and HREM observations. 29 refs., 8 figs., 3 tabs

Electronic Structure of GdCuGe Intermetallic Compound

Science.gov (United States)

Lukoyanov, A. V.; Knyazev, Yu. V.; Kuz'min, Yu. I.

2018-04-01

The electronic structure of GdCuGe intermetallic compound has been studied. Spin-polarized energy spectrum calculations have been performed by the band method with allowance for strong electron correlations in the 4 f-shell of gadolinium ions. Antiferromagnetic ordering of GdCuGe at low temperatures has been obtained in a theoretical calculation, with the value of the effective magnetic moment of gadolinium ions reproduced in fair agreement with experimental data. The electronic density of states has been analyzed. An optical conductivity spectrum has been calculated for GdCuGe; it reveals specific features that are analogous to the ones discovered previously in the GdCuSi compound with a similar hexagonal structure.

Magnetic dimerization in the frustrated spin ladder Li2Cu2O (SO4)2

Science.gov (United States)

Vaccarelli, O.; Rousse, G.; Saúl, A.; Radtke, G.

2017-11-01

The magnetic properties of Li2Cu2O (SO4)2 are investigated in the framework of density functional theory. In its high-temperature tetragonal structure, this compound appears as a rare material realization of a frustrated spin-1/2 two-leg ladder, where magnetic frustration arises from competing nearest and next-nearest interactions along the legs. Through a large magnetoelastic coupling, the triclinic distortion occurring around 125 K is shown to induce the formation of a staggered dimer structure, lifting most of the magnetic frustration.

Crystal structure of Nd4Cu2O7

International Nuclear Information System (INIS)

Pederzolli, D.R.; Attfield, J.P.

1998-01-01

The structure of Nd 4 Cu 2 O 7 (A2/m, a = 8.449 A, b = 3.759 A, c = 12.601 A, β = 109.57 ), prepared by topotactic reduction of the high-T c superconductor parent phase Nd 2 CuO 4 , has been determined from time-of-flight neutron powder diffraction data revealing a new oxygen vacancy-ordered arrangement containing cooperatively distorted Cu 2 O 3 planes in which 2- and 4- coordinate Cu - sites are present. (orig.)

Exploring the thermoelectric and magnetic properties of uranium selenides: Tl2Ag2USe4 and Tl3Cu4USe6

International Nuclear Information System (INIS)

Azam, Sikander; Khan, Saleem Ayaz; Din, Haleem Ud; Khenata, Rabah; Goumri-Said, Souraya

2016-01-01

The electronic, magnetic and thermoelectric properties of Tl 2 Ag 2 USe 4 and Tl 3 Cu 4 USe 6 compounds were investigated using the full potential linear augmented plane wave (FP-LAPW) method based on the density functional theory (DFT). The exchange correlation was treated with the generalized gradient approximation plus optimized effective Hubbard parameter and spin–orbit coupling (GGA+U+SOC). The present uranium selenides show narrow direct energy band gap values of 0.7 and 0.875 eV for Tl 2 Ag 2 USe 4 and Tl 3 Cu 4 USe 6 respectively. For both selenides U-d/f states are responsible for electrical transport properties. Uranium atoms were the most contributors in the magnetic moment compared to other atoms and show ferromagnetic nature. The spin density isosurfaces show the polarization of neighboring atoms of Uranium, such as silver/copper and selenium. Thermoelectric calculations reveal that Tl 3 Cu 4 USe 6 is more suitable for thermoelectric device applications than Tl 2 Ag 2 USe 4 . - Highlights: • Electronic, magnetic and thermoelectric properties of uranium selenides are investigated with DFT. • They show a narrow direct energy band gap of 0.7 and 0.875 eV. • U-d/f states are responsible for electrical transport properties. • Tl 3 Cu 4 USe 6 is more suitable for thermoelectric device applications than Tl 2 Ag 2 USe 4 .

Novel CuCr_2O_4 embedded CuO nanocomposites for efficient photodegradation of organic dyes

International Nuclear Information System (INIS)

Mageshwari, K.; Sathyamoorthy, R.; Lee, Jeong Yong; Park, Jinsub

2015-01-01

Graphical abstract: - Highlights: • Novel CuO–CuCr_2O_4 nanocomposites synthesized by reflux condensation method. • Methyl orange and methylene blue dye degradation studied under UV light irradiation. • Nanocomposites characterized by XRD, FESEM, TEM, EDX, UV–vis DRS and PL. • CuCr_2O_4 loading effectively enhanced the catalytic activity of CuO. - Abstract: Novel photocatalyst based on CuO–CuCr_2O_4 nanocomposites was synthesized for different Cr"3"+ concentration by reflux condensation method, and their photocatalytic activity was evaluated by monitoring the photodegradation of methyl orange (MO) and methylene blue dyes (MB) under UV light irradiation. Phase evolution by X-ray diffraction showed monoclinic CuO and tetragonal CuCr_2O_4 as the components of the prepared nanocomposites. Morphological analysis by scanning electron microscope and transmission electron microscope revealed that the incorporation of Cr"3"+ in CuO lattice alters the morphology of CuO from microsphere to cluster shape. Photoluminescence spectra of CuO–CuCr_2O_4 nanocomposites exhibited reduced PL emissions compared to pure CuO, indicating the low recombination rate of photogenerated electrons and holes. As expected, the CuCr_2O_4 loaded CuO showed enhanced photocatalytic activity for MO and MB dyes, and the kinetic studies suggest that the degradation follows pseudo-first-order kinetics. The enhanced photocatalytic activity of CuO–CuCr_2O_4 nanocomposites can be attributed to the presence of CuCr_2O_4 as an electron acceptor, which improves the effective charge separation in CuO.

Tolérance & Droit

OpenAIRE

Cottereau, Marc; Friouret, Laurent; Grabias, Fanny; Groulier, Cédric; Guimezanes, Marie; Lavergne, Benjamin; Maugard, Florian; Pacteau, Bernard; Sztulman, Marc

2018-01-01

Que reste-t-il à dire sur la tolérance ? Panacée médiatique aux problèmes de société, elle est sommairement définie comme une “indulgence pour ce qu’on ne peut pas ou ne veut pas empêcher”. De l’acception de la tolérance comme affaiblissement de la norme au comportement pragmatique de l’administration qui renonce à appliquer une sanction, en passant par la tolérance comme composante d’une société démocratique, le concept brille par son hétérogénéité. Concept à la frontière du droit, de la s...

Crystal structure of the new diamond-like semiconductor CuMn2InSe4

Indian Academy of Sciences (India)

Abstract. The crystal structure of the semiconductor compound CuMn2InSe4 was analysed using X-ray powder ... properties arising from the presence of magnetic ions in the ... by SEM technique, using a Hitachi S2500 microscope equip-.

Genome-wide target profiling of piggyBac and Tol2 in HEK 293: pros and cons for gene discovery and gene therapy

Science.gov (United States)

2011-01-01

Background DNA transposons have emerged as indispensible tools for manipulating vertebrate genomes with applications ranging from insertional mutagenesis and transgenesis to gene therapy. To fully explore the potential of two highly active DNA transposons, piggyBac and Tol2, as mammalian genetic tools, we have conducted a side-by-side comparison of the two transposon systems in the same setting to evaluate their advantages and disadvantages for use in gene therapy and gene discovery. Results We have observed that (1) the Tol2 transposase (but not piggyBac) is highly sensitive to molecular engineering; (2) the piggyBac donor with only the 40 bp 3'-and 67 bp 5'-terminal repeat domain is sufficient for effective transposition; and (3) a small amount of piggyBac transposases results in robust transposition suggesting the piggyBac transpospase is highly active. Performing genome-wide target profiling on data sets obtained by retrieving chromosomal targeting sequences from individual clones, we have identified several piggyBac and Tol2 hotspots and observed that (4) piggyBac and Tol2 display a clear difference in targeting preferences in the human genome. Finally, we have observed that (5) only sites with a particular sequence context can be targeted by either piggyBac or Tol2. Conclusions The non-overlapping targeting preference of piggyBac and Tol2 makes them complementary research tools for manipulating mammalian genomes. PiggyBac is the most promising transposon-based vector system for achieving site-specific targeting of therapeutic genes due to the flexibility of its transposase for being molecularly engineered. Insights from this study will provide a basis for engineering piggyBac transposases to achieve site-specific therapeutic gene targeting. PMID:21447194

CuAlO2 and CuAl2O4 thin films obtained by stacking Cu and Al films using physical vapor deposition

Science.gov (United States)

Castillo-Hernández, G.; Mayén-Hernández, S.; Castaño-Tostado, E.; DeMoure-Flores, F.; Campos-González, E.; Martínez-Alonso, C.; Santos-Cruz, J.

2018-06-01

CuAlO2 and CuAl2O4 thin films were synthesized by the deposition of the precursor metals using the physical vapor deposition technique and subsequent annealing. Annealing was carried out for 4-6 h in open and nitrogen atmospheres respectively at temperatures of 900-1000 °C with control of heating and cooling ramps. The band gap measurements ranged from 3.3 to 4.5 eV. Electrical properties were measured using the van der Pauw technique. The preferred orientations of CuAlO2 and CuAl2O4 were found to be along the (1 1 2) and (3 1 1) planes, respectively. The phase percentages were quantified using a Rietveld refinement simulation and the energy dispersive X-ray spectroscopy indicated that the composition is very close to the stoichiometry of CuAlO2 samples and with excess of aluminum and deficiency of copper for CuAl2O4 respectively. High resolution transmission electron microscopy identified the principal planes in CuAlO2 and in CuAl2O4. Higher purities were achieved in nitrogen atmosphere with the control of the cooling ramps.

Cu²⁺ in Layered Compounds

DEFF Research Database (Denmark)

Aramburu, J. A.; García Lastra, Juan Maria; García-Fernández, P.

2013-01-01

been analyzed using a parametrized Jahn–Teller model with an imposed strain [Reinen, D. Inorg. Chem.2012, 51, 4458]. Here, we present results of ab initio periodic supercell and cluster calculations on K2ZnF4:Cu2+, showing unequivocally that the actual origin of the unusual compressed geometry......– distances are, respectively, Rax = 193 pm and Req = 204 pm, and so the calculated distortion Rax – Req = 11 pm is three times smaller than the estimated through the parametrized Jahn–Teller model. As a salient feature, we find that if the CuF64– complex would assume a perfect octahedral geometry (Rax = Req...

Cu-O network dependence of optical charge-transfer gaps and spin-pair excitations in single-CuO2-layer compounds

International Nuclear Information System (INIS)

Tokura, Y.; Koshihara, S.; Arima, T.; Takagi, H.; Ishibashi, S.; Ido, T.; Uchida, S.

1990-01-01

Spectra of optical conductivity and magnon Raman scattering have been investigated in single crystals of a parent family of cuprate superconductors with various types of Cu-O single-layer networks. The analysis of the spectra shows the systematic dependence of the charge-transfer gaps and covalent character of Cu-O bonds on the pattern of the Cu-O network, while the spin-exchange energy is rather convergent for all the single-CuO 2 -sheet compounds

Thermoelectric properties of chalcogenide based Cu2+xZnSn1−xSe4

Directory of Open Access Journals (Sweden)

Ch. Raju

2013-03-01

Full Text Available Quaternary chalcogenide compounds Cu2+xZnSn1−xSe4 (0 ≤ x ≤ 0.15 were prepared by solid state synthesis. Rietveld powder X-ray diffraction (XRD refinements combined with Electron Probe Micro Analyses (EPMA, WDS-Wavelength Dispersive Spectroscopy and Raman spectra of all samples confirmed the stannite structure (Cu2FeSnS4-type as the main phase. In addition to the main phase, small amounts of secondary phases like ZnSe, CuSe and SnSe were observed. Transport properties of all samples were measured as a function of temperature in the range from 300 K to 720 K. The electrical resistivity of all samples decreases with an increase in Cu content except for Cu2.1ZnSn0.9Se4, most likely due to a higher content of the ZnSe. All samples showed positive Seebeck coefficients indicating that holes are the majority charge carriers. The thermal conductivity of doped samples was high compared to Cu2ZnSnSe4 and this may be due to the larger electronic contribution and the presence of the ZnSe phase in the doped samples. The maximum zT = 0.3 at 720 K occurs for Cu2.05ZnSn0.95Se4 for which a high-pressure torsion treatment resulted in an enhancement of zT by 30% at 625 K.

A requirement of TolC and MDR efflux pumps for acid adaptation and GadAB induction in Escherichia coli.

Directory of Open Access Journals (Sweden)

Kari N W Deininger

Full Text Available BACKGROUND: The TolC outer membrane channel is a key component of several multidrug resistance (MDR efflux pumps driven by H(+ transport in Escherichia coli. While tolC expression is under the regulation of the EvgA-Gad acid resistance regulon, the role of TolC in growth at low pH and extreme-acid survival is unknown. METHODS AND PRINCIPAL FINDINGS: TolC was required for extreme-acid survival (pH 2 of strain W3110 grown aerobically to stationary phase. A tolC deletion decreased extreme-acid survival (acid resistance of aerated pH 7.0-grown cells by 10(5-fold and of pH 5.5-grown cells by 10-fold. The requirement was specific for acid resistance since a tolC defect had no effect on aerobic survival in extreme base (pH 10. TolC was required for expression of glutamate decarboxylase (GadA, GadB, a key component of glutamate-dependent acid resistance (Gad. TolC was also required for maximal exponential growth of E. coli K-12 W3110, in LBK medium buffered at pH 4.5-6.0, but not at pH 6.5-8.5. The TolC growth requirement in moderate acid was independent of Gad. TolC-associated pump components EmrB and MdtB contributed to survival in extreme acid (pH 2, but were not required for growth at pH 5. A mutant lacking the known TolC-associated efflux pumps (acrB, acrD, emrB, emrY, macB, mdtC, mdtF, acrEF showed no growth defect at acidic pH and a relatively small decrease in extreme-acid survival when pre-grown at pH 5.5. CONCLUSIONS: TolC and proton-driven MDR efflux pump components EmrB and MdtB contribute to E. coli survival in extreme acid and TolC is required for maximal growth rates below pH 6.5. The TolC enhancement of extreme-acid survival includes Gad induction, but TolC-dependent growth rates below pH 6.5 do not involve Gad. That MDR resistance can enhance growth and survival in acid is an important consideration for enteric organisms passing through the acidic stomach.

Isospin symmetry of Tz =±3/2→±1/2 Gamow-Teller transitions in A=41 nuclei

Science.gov (United States)

Fujita, Y.; Shimbara, Y.; Adachi, T.; Berg, G. P.; Brown, B. A.; Fujita, H.; Hatanaka, K.; Kamiya, J.; Nakanishi, K.; Sakemi, Y.; Sasaki, S.; Shimizu, Y.; Tameshige, Y.; Uchida, M.; Wakasa, T.; Yosoi, M.

2004-11-01

Under the assumption that isospin T is a good quantum number, isobaric analog states and various analogous transitions are expected in isobars with mass number A . The strengths of Tz =±3/2→±1/2 analogous Gamow-Teller (GT) transitions and analogous M1 transitions within the A=41 isobar quartet are compared in detail. The Tz =+3/2→+1/2 GT transitions from the Jπ = 3/2+ ground state of 41K leading to excited Jπ = 1/2+ , 3/2+ , and 5/2+ states in 41Ca were measured using the ( 3He ,t) charge-exchange reaction. With a high energy resolution of 35 keV , many fragmented states were observed, and the GT strength distribution was determined up to 10 MeV excitation energy ( Ex ) . The main part of the strength was concentrated in the Ex =4 6 MeV region. A shell-model calculation could reproduce the concentration, but not so well details of the strength distribution. The obtained distribution was further compared with two results of 41Ti β decay studying the analogous Tz =-3/2→-1/2 GT strengths. They reported contradicting distributions. One-to-one correspondences of analogous transitions and analog states were assigned up to Ex =6 MeV in the comparison with one of these 41Ti β -decay results. Combining the spectroscopic information of the analog states in 41Ca and 41Sc , the most probable Jπ values were deduced for each pair of analog states. It was found that 5/2+ states carry the main part of the observed GT strength, while much less GT strength was carried by 1/2+ and 3/2+ states. The gross features of the GT strength distributions for each J were similar for the isospin analogous Tz =±3/2→±1/2 transitions, but the details were somewhat different. From the difference of the distributions, isospin-asymmetry matrix elements of ≈8 keV were deduced. The Coulomb displacement energy, which is sensitive to the configuration of states, showed a sudden increase of about 50 keV at the excitation energy of 3.8 MeV . The strengths of several M1 transitions to the

Synthesis and Characterization of an Earth-Abundant Cu2BaSn(S,Se)4 Chalcogenide for Photoelectrochemical Cell Application.

Science.gov (United States)

Shin, Donghyeop; Ngaboyamahina, Edgard; Zhou, Yihao; Glass, Jeffrey T; Mitzi, David B

2016-11-17

Cu 2 BaSnS 4-x Se x films consisting of earth-abundant metals have been examined for photocathode application. Films with different Se contents (i.e., Cu 2 BaSnS 4-x Se x with x ≤ 2.4) were synthesized using a cosputter system with post-deposition sulfurization/selenization annealing treatments. Each film adopts a trigonal P3 1 crystal structure, with progressively larger lattice constants and with band gaps shifting from 2.0 to 1.6 eV, as more Se substitutes for S in the parent compound Cu 2 BaSnS 4 . Given the suitable bandgap and earth-abundant elements, the Cu 2 BaSnS 4-x Se x films were studied as prospective photocathodes for water splitting. Greater than 6 mA/cm 2 was obtained under illumination at -0.4 V versus reversible hydrogen electrode for Pt/Cu 2 BaSnS 4-x Se x films with ∼60% Se content (i.e., x = 2.4), whereas a bare Cu 2 BaSnS 4-x Se x (x = 2.4) film yielded ∼3 mA/cm 2 at -0.4 V/RHE.

Dispersion of the linear and nonlinear optical susceptibilities of the CuAl(S1−xSex)2 mixed chaclcopyrite compounds

International Nuclear Information System (INIS)

Reshak, A. H.; Brik, M. G.; Auluck, S.

2014-01-01

Based on the electronic band structure, we have calculated the dispersion of the linear and nonlinear optical susceptibilities for the mixed CuAl(S 1−x Se x ) 2 chaclcopyrite compounds with x = 0.0, 0.25, 0.5, 0.75, and 1.0. Calculations are performed within the Perdew-Becke-Ernzerhof general gradient approximation. The investigated compounds possess a direct band gap of about 2.2 eV (CuAlS 2 ), 1.9 eV (CuAl(S 0.75 Se 0.25 ) 2 ), 1.7 eV (CuAl(S 0.5 Se 0.5 ) 2 ), 1.5 eV (CuAl(S 0.25 Se 0.75 ) 2 ), and 1.4 eV (CuAlSe 2 ) which tuned to make them optically active for the optoelectronics and photovoltaic applications. These results confirm that substituting S by Se causes significant band gaps' reduction. The optical function's dispersion ε 2 xx (ω) and ε 2 zz (ω)/ε 2 xx (ω), ε 2 yy (ω), and ε 2 zz (ω) was calculated and discussed in detail. To demonstrate the effect of substituting S by Se on the complex second-order nonlinear optical susceptibility tensors, we performed detailed calculations for the complex second-order nonlinear optical susceptibility tensors, which show that the neat parents compounds CuAlS 2 and CuAlSe 2 exhibit | χ 123 (2) (−2ω;ω;ω) | as the dominant component, while the mixed alloys exhibit | χ 111 (2) (−2ω;ω;ω) | as the dominant component. The features of | χ 123 (2) (−2ω;ω;ω) | and | χ 111 (2) (−2ω;ω;ω) | spectra were analyzed on the basis of the absorptive part of the corresponding dielectric function ε 2 (ω) as a function of both ω/2 and ω.

1D Cu(II) coordination polymer derived from 2-(2-(2,4-dioxopentan-3-ylidene)hydrazinyl)benzenesulfonate chelator and pyrazine spacer

Science.gov (United States)

Mahmudov, Kamran T.; Haukka, Matti; Sutradhar, Manas; Mizar, Archana; Kopylovich, Maximilian N.; Pombeiro, Armando J. L.

2013-02-01

Reaction of 2-(2-(2,4-dioxopentan-3-ylidene)hydrazinyl)benzenesulfonic acid (H2L) with copper(II) nitrate hydrate in the presence of pyrazine (pz) in methanol affords the coordination polymer [Cu2(μ-L)2(H2O)2(μ-pz)]n (1), where the bidentate pz molecule links two Cu(II) centres of two different dimeric units, giving rise to a one-dimensional chain. The dimeric unit [Cu2(μ-L)2(H2O)2] consists of two distorted octahedral Cu(II) centres connected via oxygen atoms of the sulfo group of the bridging L2- ligand. The extensive hydrogen bonding between the coordinated water and pz molecules leads to the formation of a supramolecular 3D associate. Compound 1 has been characterized by elemental analysis, ESI-MS, IR spectroscopy and single-crystal X-ray diffraction analysis.

Field-dependent antiferromagnetism and ferromagnetism of the two copper sublattices in Sr2Cu3O4Cl2

International Nuclear Information System (INIS)

Kastner, M.A.; Aharony, A.; Birgeneau, R.J.; Chou, F.C.; Entin-Wohlman, O.; Greven, M.; Harris, A.B.; Kim, Y.J.; Lee, Y.S.; Parks, M.E.; Zhu, Q.

1999-01-01

The Cu 3 O 4 layer in Sr 2 Cu 3 O 4 Cl 2 is a variant of the square CuO 2 lattice of the high-temperature superconductors, in which the center of every second plaquette contains an extra Cu 2+ ion. The ions that make up the conventional CuO 2 network, called CuI, have CuI-CuI exchange energy ∼130meV, and order antiferromagnetically at about 380 K; the CuII-CuII exchange is only ∼10meV, and the CuII close-quote s order at ∼40K. A study is reported here of the dependence of the magnetization on field, temperature, and crystallographic orientation for this interesting system. We show that the small permanent ferromagnetic moment, that appears when the CuI spins order, and the unusual spin rotation transitions seen most clearly for one particular direction of the magnetic field, are the result of several small bond-dependent anisotropic terms in the spin Hamiltonian that are revealed because of the frustration of the isotropic Heisenberg interaction between CuI and CuII spins. These include a term which favors collinearity of the CuI and CuII spins, which originates from quantum fluctuations, and also the pseudodipolar interaction. Some of these small interactions also come into play in other lamellar cuprates, connected with the high-T c superconductivity materials, and in many spin-chain and spin-ladder compounds. copyright 1999 The American Physical Society

Wet chemical passivation of YBa2Cu3O(7-x)

Science.gov (United States)

Vasquez, R. P.; Hunt, B. D.; Foote, M. C.

1990-01-01

Wet chemical techniques are described for treatment of YBa2Cu3O(7-x) surfaces, which result in the formation of native compounds known to have little or no reactivity to water. Suitable native compounds include CuI, BaSO4, CuS, Cu2S, YF3, and the oxalates. Formation of surface layers in which these nonreactive native compounds are major constituents is verified with X-ray photoelectron spectroscopy (XPS) measurements on YBa2Cu3O(7-x) films treated with dilute solutions of HI, H2SO4, Na2S, HF, or H2C2O4. No significant changes are observed in the XPS spectra when the sulfide, sulfate, or oxalate films are dipped in water, while the iodide and fluoride films show evidence of reaction with water. X-ray diffraction measurements show that the superconducting phase is absent in the sulfide film, but is unaffected by the oxalate and sulfate treatments.

Thioaluminogermanate M(AlS2)(GeS2)4 (M = Na, Ag, Cu): Synthesis, Crystal Structures, Characterization, Ion-Exchange and Solid-State 27Al and 23Na NMR Spectroscopy

KAUST Repository

Alahmary, Fatimah S.

2018-03-14

The new thioaluminogermanate Na(AlS2)(GeS2)4 (1) was successfully synthesized by a direct combination reaction. The compound crystallizes in the monoclinic space group P21/n (no. 14) with unit cell parameters a = 6.803(3) Å, b = 38.207(2) Å, c = 6.947(4) Å, and β = 119.17(3)°. The crystal structure is composed of a [(AlS2)(GeS2)4]− 3D polyanionic network, in which Al and Ge atoms share the atomic positions and Na cations occupy the channels and voids formed by the connection of (Ge/Al)S4 tetrahedra. The title compound shows a cation-exchange property with monovalent Ag+ and Cu+ ions at room temperature in solvent media, resulting in the formation of the isostructural compounds Ag(AlS2)(GeS2)4 (2) and Cu(AlS2)(GeS2)4 (3), respectively. The ion-exchange products Ag(AlS2)(GeS2)4 (2) and Cu(AlS2)(GeS2)4 (3) show higher air stability and narrower bandgap energies compared to those of the parent compound Na(AlS2)(GeS2)4 (1).

Thioaluminogermanate M(AlS2)(GeS2)4 (M = Na, Ag, Cu): Synthesis, Crystal Structures, Characterization, Ion-Exchange and Solid-State 27Al and 23Na NMR Spectroscopy

KAUST Repository

Alahmary, Fatimah S.; Davaasuren, Bambar; Emwas, Abdul-Hamid M.; Rothenberger, Alexander

2018-01-01

The new thioaluminogermanate Na(AlS2)(GeS2)4 (1) was successfully synthesized by a direct combination reaction. The compound crystallizes in the monoclinic space group P21/n (no. 14) with unit cell parameters a = 6.803(3) Å, b = 38.207(2) Å, c = 6.947(4) Å, and β = 119.17(3)°. The crystal structure is composed of a [(AlS2)(GeS2)4]− 3D polyanionic network, in which Al and Ge atoms share the atomic positions and Na cations occupy the channels and voids formed by the connection of (Ge/Al)S4 tetrahedra. The title compound shows a cation-exchange property with monovalent Ag+ and Cu+ ions at room temperature in solvent media, resulting in the formation of the isostructural compounds Ag(AlS2)(GeS2)4 (2) and Cu(AlS2)(GeS2)4 (3), respectively. The ion-exchange products Ag(AlS2)(GeS2)4 (2) and Cu(AlS2)(GeS2)4 (3) show higher air stability and narrower bandgap energies compared to those of the parent compound Na(AlS2)(GeS2)4 (1).

Synthesis and characterization of an energetic compound Cu(Mtta)2(NO3)2 and effect on thermal decomposition of ammonium perchlorate

International Nuclear Information System (INIS)

Yang, Qi; Chen, Sanping; Xie, Gang; Gao, Shengli

2011-01-01

Highlights: ► A new energetic compound Cu(Mtta) 2 (NO 3 ) 2 has been synthesized and structural characterized. ► Sensitivity tests reveal that the compound is insensitive to mechanical stimuli. ► Cu(Mtta) 2 (NO 3 ) 2 accelerates the decomposition of Ammonium perchlorate (AP), which is the key component of composite solid propellant. - Abstract: An energetic coordination compound Cu(Mtta) 2 (NO 3 ) 2 has been synthesized by using 1-methyltetrazole (Mtta) as ligand and its structure has been characterized by X-ray single crystal diffraction. The central copper (II) cation was coordinated by four O atoms from two Mtta ligands and two N atoms from two NO 3 − anions to form a six-coordinated and distorted octahedral structure. 2D superamolecular layer structure was formed by the extensive intermolecular hydrogen bonds between Mtta ligands and NO 3 − anions. Thermal decomposition process of the compound was predicted based on DSC and TG-DTG analyses results. The kinetic parameters of the first exothermic process of the compound were studied by the Kissinger's and Ozawa–Doyle's methods. Sensitivity tests revealed that the compound was insensitive to mechanical stimuli. In addition, compound was explored as additive to promote the thermal decomposition of ammonium perchlorate (AP) by differential scanning calorimetry.

Thermoelectric and mechanical properties of spark plasma sintered Cu3SbSe3 and Cu3SbSe4: Promising thermoelectric materials

Science.gov (United States)

Tyagi, Kriti; Gahtori, Bhasker; Bathula, Sivaiah; Toutam, Vijaykumar; Sharma, Sakshi; Singh, Niraj Kumar; Dhar, Ajay

2014-12-01

We report the synthesis of thermoelectric compounds, Cu3SbSe3 and Cu3SbSe4, employing the conventional fusion method followed by spark plasma sintering. Their thermoelectric properties indicated that despite its higher thermal conductivity, Cu3SbSe4 exhibited a much larger value of thermoelectric figure-of-merit as compared to Cu3SbSe3, which is primarily due to its higher electrical conductivity. The thermoelectric compatibility factor of Cu3SbSe4 was found to be ˜1.2 as compared to 0.2 V-1 for Cu3SbSe3 at 550 K. The results of the mechanical properties of these two compounds indicated that their microhardness and fracture toughness values were far superior to the other competing state-of-the-art thermoelectric materials.

Synthesis and the crystal and molecular structures of (H3L . Cl)[CoCl4] and H2L[CuBr4] (L is 2,4,6-Tri(N,N-dimethylamino)methylphenol)

International Nuclear Information System (INIS)

Kovalchukova, O. V.; Stash, A. I.; Strashnova, S. B.; Romashkina, E. P.; Zaitsev, B. E.

2010-01-01

The complex compounds (H 3 L . Cl)[CoCl 4 ] (I) and H 2 L[CuBr 4 ] (II), where L is 2,4,6-tri(N,N-dimethylamino)methylphenol, were isolated in the crystalline state and studied by X-ray diffraction. The organic cations were found to be outer-sphere ligands. All three nitrogen atoms of the tertiary amino groups are protonated. In compound I, the H 3 L 3+ cation exists as the cis tautomer. In compound II, the H 2 L 2+ dication exists as the trans isomer. In the crystal structure, the dications are arranged in layers via hydrogen bonds.

The crystal structure of a new ternary antimonide: TmCu4-xSb2 (x 1.065)

International Nuclear Information System (INIS)

Fedyna, L.O.; Bodak, O.I.; Fedorchuk, A.O.; Tokaychuk, Ya.O.

2005-01-01

The crystal structure of the new ternary compound TmCu 4-x Sb 2 (x 1.065) was determined by direct methods from X-ray powder data (diffractometer DRON-3M, Cu Kα-radiation). It crystallizes with the orthorhombic structure type ErFe 4 Ge 2 (low-temperature modification) and is the first representative of this structure type among known antimonides: space group Pnnm, Pearson code oP14-2.13, a = 7.00565(6) A, b = 7.83582(6) A, c = 4.25051(3) A, Z = 2. Investigated structure is an orthorhombically deformed derivative of the ZrFe 4 Si 2 structure type

Orbital topology, interlayer spin coupling, and magnetic anisotropy of the CuFeO2 compound

NARCIS (Netherlands)

Malvestuto, M.; Bondino, F.; Magnano, E.; Lummen, T. T. A.; van Loosdrecht, P. H. M.; Parmigiani, F.

2011-01-01

X-ray absorption spectroscopy performed on a CuFeO2 single crystal reveals the pivotal role of the Cu ions in the discussion of the anisotropic properties of the compound. In particular, it is shown that there is a 3d hole density on the nominal 3d(10) Cu+ ions which may lie at the origin of the

Crystal structure, Raman scattering and magnetic properties of CuCr2-xZrxSe4 and CuCr2-xSnxSe4 selenospinels

Science.gov (United States)

Pinto, C.; Galdámez, A.; Barahona, P.; Moris, S.; Peña, O.

2018-06-01

Selenospinels, CuCr2-xMxSe4 (M = Zr and Sn), were synthesized via conventional solid-state reactions. The crystal structure of CuCr1.5Sn0.5Se4, CuCr1.7Sn0.3Se4, CuCr1.5Zr0.5Se4, and CuCr1.8Zr0.2Se4 were determined using single-crystal X-ray diffraction. All the phases crystallized in a cubic spinel-type structure. The chemical compositions of the single-crystals were examined using energy-dispersive X-ray analysis (EDS). Powder X-ray diffraction patterns of CuCr1.3Sn0.7Se4 and CuCr1.7Sn0.3Se4 were consistent with phases belonging to the Fd 3 bar m Space group. An analysis of the vibrational properties on the single-crystals was performed using Raman scattering measurements. The magnetic properties showed a spin glass behavior with increasing Sn content and ferromagnetic order for CuCr1.7Sn0.3Se4.

Microanalysis on CuInSe2 compound synthesized by mechanochemical processing

International Nuclear Information System (INIS)

Wu Sumei; Xue Yuzhi; Zhang Zhihua

2010-01-01

CuInSe 2 (CIS) compound has been synthesized by mechanochemical processing (MCP) with different process parameters. The effect of milling time and different molar ratios of Cu:In:Se was investigated. The obtained materials were characterized by X-ray diffraction (XRD), scanning electron microscope (SEM), energy dispersive spectroscopy (EDS) for evaluating their crystal structure, grain size, morphology and composition. Field emission transmission electron microscopy (FETEM) was used to detect the smog particles produced during the milling. The results revealed that the obtained powder was chalcopyrite CuInSe 2 and the particle size was smaller than 5 μm after milling for 60 min. The EDS analysis indicated that the smog was volatile selenium. The composition of the products deviated from those of starting materials after MCP. The mechanism about mechanically induced self-propagating reaction which occurred during milling copper, indium and selenium powders was also discussed.

Use of response surface methodology to evaluate the effect of metal ions (Ca2+, Ni2+, Mn2+, Cu2+) on production of antifungal compounds by Paenibacillus polymyxa.

Science.gov (United States)

Raza, Waseem; Hongsheng, Wu; Qirong, Shen

2010-03-01

The effects of four metal ions (Ca(2+), Ni(2+), Mn(2+) and Cu(2+)) were evaluated on growth and production of antifungal compounds by Paenibacillus polymyxa SQR-21 and a quadratic predictive model was developed using response surface methodology (RSM). The results revealed, Mn(2+) and Ni(2+) showed most positive synergistic interactive affect on production of antifungal compounds followed by the positive interactive synergistic affect of Cu(2+) and Ni(2+) and then Mn(2+) and Cu(2+). While the interactive effect of Ca(2+) with all other three metals inhibited the production of antifungal compounds. The Mn(2+) (P=0.0384), Ni(2+) (P=0.0004) and Cu(2+) (P=0.0117) significantly affected the production of antifungal compounds while the effect of Ca(2+) (P=0.1851) was less significant. The maximum growth (OD(600)=1.55) was obtained at 500 (0), 125 (0), 100 (-2) and 37.5 (0) microM levels and the maximum size of inhibition zone (31 mm) was measured at 400 (-1), 150 (1), 400 (1) and 25 microM (-1) levels of Ca(2+), Mn(2+), Ni(2+) and Cu(2+), respectively. The RSM model provided an easy and effective way to determine the interactive effect of metal ions on production of antifungal compounds by P. polymyxa SQR-21 so that optimum media recipes can be developed to produce maximum amounts of antifungal compounds under laboratory and commercial fermentation conditions. Copyright (c) 2009 Elsevier Ltd. All rights reserved.

Contemporary zebrafish transgenesis with Tol2 and application for Cre/lox recombination experiments.

Science.gov (United States)

Felker, A; Mosimann, C

2016-01-01

Spatiotemporal transgene regulation by transgenic DNA recombinases is a central tool for reverse genetics in multicellular organisms, with excellent applications for misexpression and lineage tracing experiments. One of the most widespread technologies for this purpose is Cre recombinase-controlled lox site recombination that is attracting increasing interest in the zebrafish field. Tol2-mediated zebrafish transgenesis provides a stable platform to integrate lox cassette transgenes, while the amenability of the zebrafish embryo to drug treatments makes the model an ideal candidate for tamoxifen-inducible CreERT2 experiments. In addition, advanced transgenesis technologies such as phiC31 or CRISPR-Cas9-based knock-ins are even further promoting zebrafish transgenesis for Cre/lox applications. In this chapter, we will first introduce the basics of Cre/lox methodology, CreERT2 regulation by tamoxifen, as well as the utility of Tol2 and other contemporary transgenesis techniques for Cre/lox experiments. We will then outline in detail practical experimental steps for efficient transgenesis toward the creation of single-insertion transgenes and will introduce protocols for 4-hydroxytamoxifen-mediated CreERT2 induction to perform spatiotemporal lox transgene regulation experiments in zebrafish embryos. Last, we will discuss advanced experimental applications of Cre/lox beyond traditional lineage tracing approaches. Copyright © 2016 Elsevier Inc. All rights reserved.

SCR activity of conformed CuOx/ZrO2-SO4 catalysts

DEFF Research Database (Denmark)

Rasmussen, Søren Birk; Yates, Malcolm; Due-Hansen, Johannes

2010-01-01

CuOX/ZrO2-SO4 catalysts have been synthesised as conformed materials with the use of sepiolite as agglomerant and the performance in the NH3-SCR reaction with relation to biomass fired boiler units have been studied. The optimal Cu-loading of the catalysts is 3 wt.% CuO, both in terms of activity...

Low-temperature structural transition in the quasi-one-dimensional spin-1/2 compound L i2C u2O (SO4) 2

Science.gov (United States)

Rousse, G.; Rodríguez-Carvajal, J.; Giacobbe, C.; Sun, M.; Vaccarelli, O.; Radtke, G.

2017-04-01

A thorough structural exploration has been made on the quasi-one-dimensional S =1 /2 compound L i2C u2O (SO4) 2 by neutron and synchrotron x-ray diffraction. It reveals the occurrence of a structural transition at 125 K, characterized by a lowering of symmetry from P 42/m to P 1 ¯ , which is possibly driven by an exchange striction mechanism. This transition involves a dimerization of some Cu in the edge-sharing tetrahedral Cu chains. A symmetry mode analysis indicates that one representation, Γ3+Γ4+ , dominates the structural transition. Interestingly, no intermediate structure with P 112 /m symmetry is observed experimentally. Lastly, temperature dependent magnetic susceptibility measurements and neutron diffraction reveal that the magnetic ground state of this compound is a spin-singlet with a spin gap, characterized by the absence of long-range magnetic order down to 1.7 K.

Copper(II) manganese(II) orthophosphate, Cu_0.5Mn_2.5(PO₄)₂

DEFF Research Database (Denmark)

Warner, Terence Edwin; Bond, Andrew; Foghmoes, Søren Preben Vagn

2011-01-01

The title compound, Cu0.5Mn2.5(PO4)2, is a copper-manganese phosphate solid solution with the graftonite-type structure, (Mn,Fe,Ca,Mg)3(PO4)2. The structure has three distinct metal cation sites, two of which are occupied exclusively by MnII, and one of which accommodates CuII. Incorporation of C......II into the structure distorts the coordination geometry of the metal cation site from 5-coordinate square-pyramidal towards 4-coordinate flattened tetrahedral, and serves to contract the structure principally along the c axis....

Superconductivity in a new YBaCuO compound at 105 K

International Nuclear Information System (INIS)

Kirschner, I.; Bankuti, J.; Gal, M.; Torkos, K.; Solymos, K.G.; Horvath, G.

1987-01-01

A superconducting transition has been detected in a (Y 0.8 Ba 0.2 )(CuO 4-δ ) 2 compound by electrical and magnetic measurements. The resistivity begins to decrease at 173 K and the zero-resistivity state sets in at 105 K

TOL plasmid transfer during bacterial conjugation in vitro and rhizoremediation of oil compounds in vivo

International Nuclear Information System (INIS)

Jussila, Minna M.; Zhao, Ji; Suominen, Leena; Lindstroem, Kristina

2007-01-01

Molecular profiling methods for horizontal transfer of aromatics-degrading plasmids were developed and applied during rhizoremediation in vivo and conjugations in vitro. pWW0 was conjugated from Pseudomonas to Rhizobium. The xylE gene was detected both in Rhizobium galegae bv. officinalis and bv. orientalis, but it was neither stably maintained in orientalis nor functional in officinalis. TOL plasmids were a major group of catabolic plasmids among the bacterial strains isolated from the oil-contaminated rhizosphere of Galega orientalis. A new finding was that some Pseudomonas migulae and Pseudomonas oryzihabitans strains harbored a TOL plasmid with both pWW0- and pDK1-type xylE gene. P. oryzihabitans 29 had received the archetypal TOL plasmid pWW0 from Pseudomonas putida PaW85. As an application for environmental biotechnology, the biodegradation potential of oil-polluted soil and the success of bioremediation could be estimated by monitoring changes not only in the type and amount but also in transfer of degradation plasmids. - Horizontal transfer of degradation plasmids in the oil-contaminated rhizosphere reveals the dynamic nature of the intrinsic biodegradation potential

Isospin symmetry of T-z=+/- 3/2 ->+/- 1/2 Gamow-Teller transitions in A=41 nuclei

NARCIS (Netherlands)

Fujita, Y; Shimbara, Y; Adachi, T; Berg, GPA; Fujita, H; Hatanaka, K; Kamiya, J; Nakanishi, K; Sakemi, Y; Sasaki, S; Shimizu, Y; Tameshige, Y; Uchida, M; Wakasa, T; Yosoi, M

2004-01-01

Under the assumption that isospin T is a good quantum number, isobaric analog states and various analogous transitions are expected in isobars with mass number A. The, strengths of T-z = +/-3/2 --> 1/2 analogous Gamow-Teller (GT) transitions and analogous M1 transitions within the A = 41 isobar

Isospin symmetry of T-z=+/- 3/2 ->+/- 1/2 Gamow-Teller transitions in A=41 nuclei

NARCIS (Netherlands)

Fujita, Y; Shimbara, Y; Adachi, T; Berg, GPA; Fujita, H; Hatanaka, K; Kamiya, J; Nakanishi, K; Sakemi, Y; Sasaki, S; Shimizu, Y; Tameshige, Y; Uchida, M; Wakasa, T; Yosoi, M

Under the assumption that isospin T is a good quantum number, isobaric analog states and various analogous transitions are expected in isobars with mass number A. The, strengths of T-z = +/-3/2 --> 1/2 analogous Gamow-Teller (GT) transitions and analogous M1 transitions within the A = 41 isobar

Magnetic Excitations in Weakly Coupled Spin Dimers and Chains Material Cu2Fe2Ge4O13

International Nuclear Information System (INIS)

Masuda, Takatsugu; Zheludev, Andrey I.; Sales, Brian C.; Imai, S.; Uchinokura, K.; Park, S.

2005-01-01

Magnetic excitations in a weakly coupled spin dimers and chains compound Cu 2 Fe 2 Ge 4 O 13 are measured by inelastic neutron scattering. Both structure factors and dipsersion of low-energy excitations up to 10 meV energy transfer are well described by a semiclassical spin wave theory involving interacting Fe 3+ (S=5/2) chains. Additional dispersionsless excitations are observed at higher energies, at ℎω=24 meV, and associated with singlet-triplet transitions within Cu 2+ dimers. Both types of excitations can be understood by treating weak interactions between the Cu 2+ and Fe 3+ subsystems at the level of the mean-field random phase approximation. However, this simple model fails to account for the measured temperature dependence of the 24 meV mode.

Reduction of chromium (VI) on the hetero-system CuBi2O4/TiO2 under solar light

Science.gov (United States)

Lahmar, H.; Benamira, M.; Akika, F. Z.; Trari, M.

2017-11-01

The CuBi2O4/TiO2 heterojunction was tested with success for the photo-catalytic reduction of chromate ions under sunlight. CuBi2O4, prepared by nitrate process, was characterised photo-electrochemically. The oxide is stable against photo corrosion by consumption of holes in presence of oxalic acid. The light absorption promotes electrons in the conduction band of the sensitizer (CuBi2O4) with a very negative potential (-1.74 VSCE) to participate in the exchange of the electron with HCrO4-. The enhanced activity is due to electron injection of activated CuBi2O4 into TiO2-CB (-0.97 VSCE). The band gap of the semiconductor CuBi2O4 is 1.50 eV with a direct optical transition. This compound is a p-type semiconductor with a flat band potential of -0.39 VSCE and activation energy of 0.18 eV. The electrochemical impedance spectroscopy was undertaken to study the semiconductor/electrolyte interfacial phenomena. The photoactivity on the heterojunction is strongly enhanced. A remarkable performance is obtained in less than 4 h for a concentration of 30 mg in (Cr (VI)) at pH ∼ 4 and a dose of 1 mg/mL; a 98% reduction has been obtained. The kinetic of chromate photoreduction is well described by the Langmuir-Hinshelwood model. The chromate elimination obeys to a pseudo-first order kinetic with an apparent rate constant of 0.014 min-1.

An experimental investigation of ionic transport properties in CuI-Ag2WO4 and CuI-Ag2CrO4 mixed systems

International Nuclear Information System (INIS)

Suthanthiraraj, S. Austin; Premchand, Y. Daniel

2004-01-01

The phenomenon of ionic transport in the case of two different mixed systems (CuI) (1-x) -(Ag 2 WO 4 ) x (0.15= (1-y) -(Ag 2 CrO 4 ) y (0.15= -3 Scm -1 for the composition (CuI) 0.45 -(Ag 2 WO 4 ) 0.55 and 1.1x10 -4 Scm -1 in the case of (CuI) 0.55 -(Ag 2 CrO 4 ) 0.45 at room temperature has been discussed in terms of the observed characteristics

Spontaneous germline excision of Tol1, a DNA-based transposable element naturally occurring in the medaka fish genome.

Science.gov (United States)

Watanabe, Kohei; Koga, Hajime; Nakamura, Kodai; Fujita, Akiko; Hattori, Akimasa; Matsuda, Masaru; Koga, Akihiko

2014-04-01

DNA-based transposable elements are ubiquitous constituents of eukaryotic genomes. Vertebrates are, however, exceptional in that most of their DNA-based elements appear to be inactivated. The Tol1 element of the medaka fish, Oryzias latipes, is one of the few elements for which copies containing an undamaged gene have been found. Spontaneous transposition of this element in somatic cells has previously been demonstrated, but there is only indirect evidence for its germline transposition. Here, we show direct evidence of spontaneous excision in the germline. Tyrosinase is the key enzyme in melanin biosynthesis. In an albino laboratory strain of medaka fish, which is homozygous for a mutant tyrosinase gene in which a Tol1 copy is inserted, we identified de novo reversion mutations related to melanin pigmentation. The gamete-based reversion rate was as high as 0.4%. The revertant fish carried the tyrosinase gene from which the Tol1 copy had been excised. We previously reported the germline transposition of Tol2, another DNA-based element that is thought to be a recent invader of the medaka fish genome. Tol1 is an ancient resident of the genome. Our results indicate that even an old element can contribute to genetic variation in the host genome as a natural mutator.

Magnetic behaviour of a new compound, Eu{sub 2}CuSi{sub 3}

Energy Technology Data Exchange (ETDEWEB)

Majumdar, Subham; Mallik, R; Sampathkumaran, E V [Tata Institute of Fundamental Research, Mumbai (India)

1999-07-01

As a part of our program to synthesize new ternary Eu compounds, we report here the formation of Eu{sub 2}CuSi{sub 3} for the first time and its magnetic behaviour by magnetic susceptibility, electrical-resistivity and heat-capacity measurements. This compound is found to crystallize in an AlB{sub 2}-derived hexagonal structure. The results establish that Eu ions are divalent, undergoing long-range ferromagnetic-ordering below 38 K. (author)

Magnetism of CuCl{sub 2}·2D{sub 2}O and CuCl{sub 2}·2H{sub 2}O, and of CuBr{sub 2}·6H{sub 2}O

Energy Technology Data Exchange (ETDEWEB)

DeFotis, G.C., E-mail: gxdefo@wm.edu [Department of Chemistry, College of William and Mary, Williamsburg, VA 23187 (United States); Hampton, A.S.; Van Dongen, M.J.; Komatsu, C.H.; Benday, N.S.; Davis, C.M. [Department of Chemistry, College of William and Mary, Williamsburg, VA 23187 (United States); Hays, K.; Wagner, M.J. [Department of Chemistry, George Washington University, Washington, D.C. 20052 (United States)

2017-07-15

Highlights: • CuCl{sub 2}·2D{sub 2}O is examined magnetically and compared with CuCl{sub 2}·2H{sub 2}O. • Slightly lower magnetic characteristic temperatures occur for deuterated dihydrate. • The new compound CuBr{sub 2}·6H{sub 2}O is examined magnetically. • Unexpected relationships appears between magnetic behaviors of CuBr{sub 2}·6H{sub 2}O and CuBr{sub 2}. • Two alternative monoclinic unit cells can account for diffraction data on CuBr{sub 2}·6H{sub 2}O. - Abstract: The magnetic properties of little examined CuCl{sub 2}·2D{sub 2}O are studied and compared with those of CuCl{sub 2}·2H{sub 2}O. New CuBr{sub 2}·6H{sub 2}O is also examined. Susceptibility maxima appear for chlorides at 5.35 and 5.50 K, in the above order, with estimated antiferromagnetic ordering at 4.15 and 4.25 K. Curie-Weiss fits yield g of 2.210 and 2.205, and Weiss θ of −6.0 and −4.7 K, respectively, in χ{sub M} = C/(T − θ). One-dimensional Heisenberg model fits to susceptibilities, including interchain exchange in a mean-field approximation, are performed. Interchain exchange is significant but much weaker than intrachain. The bromide hexahydrate strongly differs magnetically from any chloride hydrate, but exhibits notable similarities and differences compared to previously studied CuBr{sub 2}. A broad susceptibility maximum occurs near 218 K, only 4% lower than for CuBr{sub 2}, but with almost twice the magnitude. Powder X-ray diffraction data for CuBr{sub 2}·6H{sub 2}O may be best accounted for by a monoclinic unit cell that is metrically orthorhombic. The volume per formula unit is consistent with trends in metal ionic radii. However, an alternative monoclinic cell with 5% smaller volume more readily rationalizes the magnetism.

Structure and phase composition of Al-Ce-Cu system alloys in range of quasi-binary Al-Al8CeCu4 section

International Nuclear Information System (INIS)

Belov, N.A.; Khvan, A.V.

2007-01-01

The phase diagram of the Al-Cu-Ce system in the quasibinary section area of Al-Al 8 CeCu 4 has been investigated by metallographic, thermal, micro-X-ray spectral and X-ray structural analyses. The parameters of the eutectic reaction L→(Al)+CeCu 4 Al 8 : T=610 Deg C were found out; the composition was 14% Cu and 7% Ce. This eutectics is of a disperse structure and the ternary compound contained is capable of fragmentation and spheroidizing in the heating process (starting from 540 Deg C). It was demonstrated that the area of optimal (Al)+CeCu 4 Al 8 eutectics-based alloy compositions was within the narrow limits. That is related to the fact that at a comparatively little variation of the Cu:Ce=2 ratio solidus sharply decreases and, as a result, the crystallization interval considerably extends [ru

Assembly of bicyclic or monocyclic clusters from [(η5-C5Me5)2Mo2(μ3-S)4(CuMeCN)2]2+ with tetraphosphine or N,P mixed ligands: syntheses, structures and enhanced third-order NLO performances.

Science.gov (United States)

Ren, Zhi-Gang; Sun, Sha; Dai, Min; Wang, Hui-Fang; Lü, Chun-Ning; Lang, Jian-Ping; Sun, Zhen-Rong

2011-09-07

Reactions of the preformed cluster [(η(5)-C(5)Me(5))(2)Mo(2)(μ(3)-S)(4)Cu(2)(MeCN)(2)](ClO(4))(2) (1) with two tetraphosphine ligands, 1,4-N,N,N',N'-tetra(diphenylphosphanylmethyl)benzene diamine (dpppda) and N,N,N',N'-tetra(diphenylphosphanylmethyl)ethylene diamine (dppeda), produced two bicyclic clusters {[(η(5)-C(5)Me(5))(2)Mo(2)(μ(3)-S)(4)Cu(2)](2)(L)}(ClO(4))(4) (3: L = dpppda; 4: L = dppeda). Analogous reactions of 1 or [(η(5)-C(5)Me(5))(2)Mo(2)(μ(3)-S)(4)Cu(2)(MeCN)(2)](PF(6))(2) (2) with two N,P mixed ligands, N,N-bi(diphenylphosphanylmethyl)-2-aminopyridine (bdppmapy) and N-diphenylphosphanylmethyl-4-aminopyridine (dppmapy), afforded two monocyclic clusters {[(η(5)-C(5)Me(5))(2)Mo(2)(μ(3)-S)(4)Cu(2)](2)(L)(2)}X(4) (5: L = bdppmapy, X = ClO(4); 6: L = dppmapy, X = PF(6)). Compounds 3-6 were fully characterized by elemental analysis, IR spectra, UV-vis spectra, (1)H and (31)P{(1)H} NMR spectra, ESI-MS and single-crystal X-ray crystallography. In the tetracations of 3-6, two cubane-like [Mo(2)(μ(3)-S)(4)Cu(2)] cores are linked either by one dpppda or dppeda bridge to form a bicyclic structure or by a pair of bdppmapy or dppmapy bridges to afford a monocyclic structure. The third-order nonlinear optical (NLO) properties of 1 and 3-6 in MeCN were also investigated by femtosecond degenerate four-wave mixing (DFWM) technique with a 50 fs pulse width at 800 nm. Compounds 3-6 exhibited enhanced third-order NLO performances relative to that of 1. This journal is © The Royal Society of Chemistry 2011

Microstructural evaluation of interfacial intermetallic compounds in Cu wire bonding with Al and Au pads

International Nuclear Information System (INIS)

Kim, Hyung Giun; Kim, Sang Min; Lee, Jae Young; Choi, Mi Ri; Choe, Si Hyun; Kim, Ki Hong; Ryu, Jae Sung; Kim, Sangshik; Han, Seung Zeon; Kim, Won Yong; Lim, Sung Hwan

2014-01-01

A comparative study on the difference in interfacial behavior of thermally aged Cu wire bonding with Al and Au pads was conducted using transmission electron microscopy. During high-temperature lifetime testing of Cu wire bonding with Al and Au pads at 175 °C for up to 2000 h, different growth rates and growth characteristics were investigated in the Cu–Al intermetallic compounds (IMCs), including CuAl 2 , CuAl and Cu 9 Al 4 , and in the Cu–Au IMCs, including (Au,Cu), Cu 3 Au and (Cu,Au). Because of the lower growth rates and greater ductility of Cu–Au IMCs compared to those of Cu–Al IMCs, the Cu wire bonding with the Au pad showed relatively better thermal aging properties of bond pull strength and ball shear strength than those with the Al pad counterpart. In this study, the coherent interfaces were found to retard the growth of IMCs, and a variety of orientation relationships between wire, pad and interfacial IMCs were identified

Effect of Cu4Ti compound formation on the characteristics of NbTi accelerator magnet wire

International Nuclear Information System (INIS)

Garber, M.; Suenaga, M.; Sampson, W.B.; Sabatini, R.L.

1985-01-01

High critical current density, J/sub c/ > 2500 A/mm 2 , and small filament diameter, d approx. 3 μm, are required in multifilamentary NbTi wire used for superconducting accelerator magnets. Wires obtained from various commercial sources had J/sub c/'s in the range 1000 to 2800 A/mm 2 amd d's in the range 1 to 23 μm. The filaments were examined by means of scanning electron microscopy in order to determine the reason for the variation in J/sub c/. It was found that the filaments in high J/sub c/ wires had clean smooth surfaces and uniform cross section along their lengths. Filaments in low J/sub c/ wires show formation of Cu 4 Ti compound particles on their surfaces and large variations in cross section. The lower critical current measured in these wires is believed to be largely due to this effect. The superconducting-normal state transition is relatively wide in these wires

Facile synthesis of SiO{sub 2}@Cu{sub x}O@TiO{sub 2} heterostructures for catalytic reductions of 4-nitrophenol and 2-nitroaniline organic pollutants

Energy Technology Data Exchange (ETDEWEB)

Zelekew, Osman Ahmed; Kuo, Dong-Hau, E-mail: dhkuo@mail.ntust.edu.tw

2017-01-30

Highlights: • The synthesis of SiO{sub 2}@Cu{sub x}O@TiO{sub 2}catalystwasillustrated (*). • The p-n junction between p-type Cu{sub x}O and n-type TiO{sub 2} built electric field. • The electric field results in avoiding the recombination of electron and hole. • The n-type TiO{sub 2} rich in electron outward facilitates the reduction. - Abstract: Herein, we designed the p-type Cu{sub x}O (x = 1 or 2) nanoparticles deposited on SiO{sub 2} spherical particle inside and coated with thin layered n-type TiO{sub 2} semiconductors outside for reduction purpose. The composite material, abbreviated as SiO{sub 2}@Cu{sub x}O@TiO{sub 2}, was characterized. The catalytic performance of the composite was tested for the reductions of 4-nitrophenol (4-NP) and 2-nitroaniline (2-NA). Complete reductions of 4-NP and 2-NA took, 210 and 150 s, respectively. The catalytic efficiency of the composite material may be associated with electron and hole separation resulted from the p-n junction formation between p-type Cu{sub x}O and n-type TiO{sub 2} and the built-in electric field. Moreover, the hydride ion and electrons released from NaBH{sub 4} together with outward electrons from n-type TiO{sub 2}, synergistically, are also responsible for the reduction of nitro aromatic compounds. Our design of composite material from low-priced metal oxides was successful towards reduction of nitro-aromatic compounds.

Cu{sub 2}ZnSnS{sub 4} thin films obtained by sulfurization of evaporated Cu{sub 2}SnS{sub 3} and ZnS layers: Influence of the ternary precursor features

Energy Technology Data Exchange (ETDEWEB)

Robles, V.; Guillén, C., E-mail: c.guillen@ciemat.es; Trigo, J.F.; Herrero, J.

2017-04-01

Highlights: • Kesterite Cu{sub 2}ZnSnS{sub 4} is got by sulfurization of evaporated Cu{sub 2}SnS{sub 3} and ZnS layers. • Smooth films are obtained by decreasing the growth temperature of Cu{sub 2}SnS{sub 3}. • The lattice strain and the electrical conductivity increase with the Cu-content. • The energy gap diminishes as the Cu-content and/or the surface roughness increase. - Abstract: Cu{sub 2}ZnSnS{sub 4} (CZTS) thin films have been grown by sulfurization of Cu{sub 2}SnS{sub 3} (CTS) and ZnS layers evaporated on glass substrates. Four CTS precursor films have been tested, with two different atomic compositions (Cu/Sn = 1.7 and Cu/Sn = 2.1) and substrate temperatures (350 and 450 °C), together with analogous ZnS layers deposited by maintaining the substrate at 200 °C. The sulfurization of the CTS and ZnS stacked layers was performed at 500 °C during 1 h. The evolution of the crystalline structure, morphology, optical and electrical properties from each CTS precursor to the CZTS compound has been studied, especially the influence of the ternary precursor features on the quaternary film characteristics. The kesterite structure has been identified after sulfurization of the various samples, with main (112) orientation and mean crystallite sizes S{sub 112} = 40–56 nm, being higher for the Cu-poor compositions. The CZTS average roughness has varied in a wide interval R{sub a} = 8–66 nm, being directly related to the CTS precursor layer, which becomes rougher for a higher deposition temperature or Cu content. Besides, the band gap energy and the electrical resistivity of the CZTS films have changed in the ranges E{sub g} = 1.54–1.64 eV and ρ = 0.2–40 Ωcm, both decreasing when the Cu content and/or the surface roughness increase.

Lattice parameters values and phase diagram for the Cu2Zn1-zFezGeSe4 alloy system

International Nuclear Information System (INIS)

Caldera, D.; Quintero, M.; Morocoima, M.; Quintero, E.; Grima, P.; Marchan, N.; Moreno, E.; Bocaranda, P.; Delgado, G.E.; Mora, A.E.; Briceno, J.M.; Fernandez, J.L.

2008-01-01

X-ray powder diffraction and differential thermal analysis (DTA) measurements were made on polycrystalline samples of the Cu 2 Zn 1-z Fe z GeSe 4 alloy system. The diffraction patterns were used to show the equilibrium conditions and to estimate crystalline parameter values. It was found that, at room temperature, a single phase solid solution with the tetragonal stannite α structure (I4-bar2m) occurs across the whole composition range. The DTA thermograms were used to construct the phase diagram of the Cu 2 Zn 1-z Fe z GeSe 4 alloy system. It was confirmed that the Cu 2 ZnGeSe 4 compound melts incongruently. It was observed that undercooling effects occur for samples with z > 0.9

Phase transition study in a [Cu2 HgI4:0⋅xAgI] mixed composite system

Indian Academy of Sciences (India)

Administrator

Diffraction, thermal analysis of compound, Ag2HgI4,. Cu2HgI4, Tl2HgI4 ... nitrogen atmosphere (200 ml/min) at a heating rate of. 5°C per min and a ..... Bates J B and Farington G C 1981 Proceedings of the interna- tional conference on fast ...

La2CuO4+δ: Synthesis under high oxygen pressure and study of phase relations and energetics

International Nuclear Information System (INIS)

Rapp, R.P.; Mehta, A.; DiCarlo, J.; Navrotsky, A.

1994-01-01

High oxygen pressures have been achieved in a piston-cylinder apparatus using a double capsule assembly consisting of a sealed outer Au capsule, containing an oxygen source (KMnO 4 ), and an inner, open Pt capsule containing the sample. Using this technique, La 2 CuO 4 was annealed at 800 degree C, 5--25 kbar for 2--4 h. Transposed temperature drop calorimetry at 704 degree C was used to determine the enthalpy of oxidation, and weight loss measurements characterized the oxygen nonstoichiometry, δ, in La 2 CuO 4+δ , in the high-pressure, oxygen annealed samples. For samples analyzed at room temperature, x-ray diffraction measurements show that beyond δ∼0.10--0.13, additional oxygen is accommodated in a perovskite-like LaCuO 3-α phase. An analysis of the thermochemical measurements indicates that the nature of holes in La 2 CuO 4+δ could change in the range of δ∼0.03--0.06. 16,17 It is further suggested that the observed change in the thermochemical behavior in the range of δ∼0.01--0.06 could be the driving influence behind the spinodal decomposition of La 2 CuO 4+δ at low temperatures (Dabrowski et al. 10 )

Positron annihilation study in La2CuO4

International Nuclear Information System (INIS)

Kubo, Y.; Asano, S.

1992-01-01

The positron annihilation study for La 2 CuO 4 are performed using the full-potential linearized augmented-plane-wave(FLAPW) calculated electron and positron densities. The electron-positron momentum density(EPMD) is computed, and the well known Lock-Crisp-West(LCW) zone folding of the EPMD is produced. In the LCW analysis, small residual variations of order about 3 % are observed. The calculations show that the relative weights of the Fermi surface discontinuities are substantially altered due to the positron preferentially sampling the Cu-O plane region

Facile synthesis of Cu/tetrapod-like ZnO whisker compounds with enhanced photocatalytic properties

Science.gov (United States)

Liu, Hong; Liu, Huarong; Fan, Ximei

2017-09-01

Cu/tetrapod-like ZnO whisker (T-ZnOw) compounds were successfully synthesized using N2H4 \\cdot H2O as a reducing agent by a simple reduction method without any insert gas at room temperature. The crystal phase composition and morphology of the as-prepared samples were investigated by XRD, SEM and FESEM tests. The photocatalytic property of the as-prepared samples was detected by the degradation of methyl orange (MO) aqueous solution under UV irradiation. It can be found that Cu nanoparticles (CuNPs) dispersed on the surface of T-ZnOw increased with the increasing of Cu/Zn molar ratios (Cu/Zn MRs), and an octahedral structure of CuNPs was obtained when the sample was prepared with less than and equal to 7.30% Cu/Zn MR, but tended to a spherical or nanorod structure of CuNPs densely arranged on the surface of T-ZnOw, which is prepared by Cu/Zn MRs up to 22.00%. All the compounds exhibited excellent photocatalytic activity in decomposing of MO than T-ZnOw, the photocatalytic property of the samples increased with the increasing of Cu/Zn MRs up to 7.30%, while it decreases when further increasing the Cu/Zn MRs. The Schottky barrier of the Cu/T-ZnOw compound can effectively capture photoinduced electrons from the interface and enhanced the photocatalytic property of T-ZnOw.

A common behaviour of thermoelectric layered cobaltites: incommensurate spin density wave states in [Ca2Co4/3Cu2/3O4]0.62[CoO2] and [Ca2CoO3]0.62[CoO2

International Nuclear Information System (INIS)

Sugiyama, J; Brewer, J H; Ansaldo, E J; Itahara, H; Dohmae, K; Xia, C; Seno, Y; Hitti, B; Tani, T

2003-01-01

Magnetism of a misfit layered cobaltite [Ca 2 Co 4/3 Cu 2/3 O 4 ] x RS [CoO 2 ] (x ∼ 0.62, RS denotes a rocksalt-type block) was investigated by a positive muon spin rotation and relaxation (μ + SR) experiment. A transition to an incommensurate (IC) spin density wave (SDW) state was found below 180 K (= T C on ); and a clear oscillation due to a static internal magnetic field was observed below 140 K(= T C ). Furthermore, an anisotropic behaviour of the zero-field μ + SR experiment indicated that the IC-SDW lies in the a-b plane, with oscillating moments directed along the c axis. These results were quite similar to those for the related compound [Ca 2 CoO 3 ] 0.62 RS [CoO 2 ], i.e., Ca 3 Co 4 O 9 . Since the IC-SDW field in [Ca 2 Co 4/3 Cu 2/3 O 4 ] 0.62 RS [CoO 2 ] was approximately the same as those in pure and doped [Ca 2 CoO 3 ] 0.62 RS [CoO 2 ], it was concluded that the IC-SDW exists in the [CoO 2 ] planes

Magnetic properties of nanostructured CuFe2O4

DEFF Research Database (Denmark)

Jiang, Jianzhong; Goya, G.F.; Rechenberg, H.R.

1999-01-01

The structural evolution and magnetic properties of nanostructured copper ferrite, CuFe2O4, have been investigated by X-ray diffraction, Mossbauer spectroscopy, and magnetization measurements. Nanometre-sized CuFe2O4 particles with a partially inverted spinel structure were synthesized by high...

X-ray photo-emission studies of Cu1-xTlxBa2Ca3Cu4O12-y superconductor thin films

International Nuclear Information System (INIS)

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

2006-01-01

X-ray photo-emission spectroscopy (XPS) studies of Cu 1-x Tl x Ba 2 Ca 3 Cu 4 O 12-y superconductor thin films have been carried out for understanding the mechanism of superconductivity and to find out the reasons for the increase of zero resistivity critical temperature T c (R = 0) with post-annealing in a nitrogen atmosphere. It is observed from these studies that reduction of charge state of thallium is a source of doping of carriers to the CuO 2 planes. The reduced charge state of thallium (i.e. Tl 1+ ) promotes lower oxygen concentration in the charge reservoir layer, which possibly results in movement of electrons to the conducting CuO 2 planes. The higher density of electrons in the CuO 2 planes optimizes the hole concentration 'n p ' in these planes. The reduced charge state of thallium in the Cu 1-x Tl x Ba 2 O 4-δ charge reservoir layer is also supported by a shift of the Ba 3d 5/2 and Ba 3d 3/2 XPS lines to lower binding energies with post-annealing in nitrogen atmosphere. Moreover, the movement of the valance band spectrum to lower binding energies suggested that the electronic density of states changes in the valance band with the post-annealing in nitrogen, which possibly becomes a source of doping of carriers to the CuO 2 planes. The increased doping of electrons to the CuO 2 planes optimizes the Fermi-vector K F and Fermi-velocity V F of the carriers and increases the T c (R = 0) of final compound

Crystal substructure and physical properties of the superconducting phase Bi4(Sr,Cr)6Cu4O16μ/sub x/

International Nuclear Information System (INIS)

Tarascon, J.M.; Le Page, Y.; Barboux, P.; Bagley, B.G.; Greene, L.H.; McKinnon, W.R.; Hull, G.W.; Giroud, M.; Hwang, D.M.

1988-01-01

We have isolated a high-T/sub c/ phase in the Bi-Sr-Ca-Cu-O system of composition Bi 4 (Sr,Ca) 6 Cu 4 O 16 μ/sub x/. The crystal substructure has a tetragonal unit cell (a = 3.817 A, c = 30.6 A) with similarities to both the oxygen-defect perovskites YBa 2 Cu 3 O 7 √/sub x/ and the K 2 NiF 4 structure of La 2 CuO 4 . The oxygen content, determined by titration and thermogravimetric analysis (TGA) experiments, corresponds to a formal oxidation state Cu(2.15). Oxygen can be reversibly depleted in an argon ambient in an amount corresponding to the reduction of the Cu(III) into Cu(II). The compound has a metalliclike resistance above its T/sub c/ near 85 K. Processing this precursor compound by heating to temperatures near its melting point (885 0 C) produces a sharp resistivity drop near 110 K that we show by ac susceptibility and Meissner effect is due to a superconducting transition

Coexistence of superconductivity and magnetism in Er{sub 2}Ba{sub 4}Cu{sub 7}O{sub 14.3}

Energy Technology Data Exchange (ETDEWEB)

Mesot, J; Boettger, G; Fischer, P [Paul Scherrer Inst. (PSI), Villigen (Switzerland); Suard, E [Institut Max von Laue - Paul Langevin (ILL), 38 - Grenoble (France); Berastegui, P

1997-09-01

The Er{sub 2}Ba{sub 4}Cu{sub 7}O{sub 14+{delta}} compounds show a very interesting behaviour upon removing of oxygen. Although the samples remain superconducting when going from {delta}=1 to {delta}=0, our low temperature elastic and inelastic measurements ({delta}<14.3) strongly indicate that a magnetic field is present at the Er site. Such a field could be generated by magnetically active Cu atoms in one of the neighbouring CuO{sub 2} planes. (author) 3 figs., 2 refs.

Microstructure and tribological properties of Ti–Cu intermetallic compound coating

International Nuclear Information System (INIS)

Guo, Chun; Zhou, Jiansong; Yu, Youjun; Wang, Lingqian; Zhou, Huidi; Chen, Jianmin

2012-01-01

Highlights: ► Ti–Cu coating has been synthesized on pure Ti substrate by laser cladding. ► Microstructure and tribological properties of Ti–Cu coating were analyzed. ► The prepared Ti–Cu intermetallic compound coating has excellent wear resistance. -- Abstract: Ti–Cu intermetallic compound coating has been in situ synthesized successfully on pure Ti substrate by laser cladding using copper powder as the precursor. It has been found that the prepared coating mainly contains of TiCu, TiCu 3 , Ti 3 Cu, and Ti phases. The transmission electron microscopy results conform further the existence of Ti–Cu intermetallic compound in the fabricated coating. Tribological properties of the prepared Ti–Cu intermetallic compound coating were systematically evaluated. It was found that normal loads and sliding speeds have a strong influence on the friction coefficient and wear rate of Ti–Cu intermetallic compound coating. Namely, the friction coefficient of the Ti–Cu intermetallic compound coating decreased with increasing normal load and sliding speed. The wear rate of the Ti–Cu intermetallic compound coating decreased rapidly with increasing sliding speed, while the wear rate increased as the normal load increased.

Cu-62, Cu-64 and Cu-66 production with 4.2 MeV deuterons; Produccion de {sup 62} Cu y {sup 64} Cu con deuterones de 4,2 MeV

Energy Technology Data Exchange (ETDEWEB)

Avila, Mario; Morales, J R; Riquelme, H O [Chile Univ., Santiago (Chile). Facultad de Ciencias. Dept. de Fisica

1997-12-31

Full text: The natural copper irradiation with deuterons produces the Cu-62, Cu-64 and Cu-66 radionuclides. Of two radioisotopes, those with deficiencies in neutrons, are applied in nuclear medicine diagnostic processes, mainly for the nuclear characteristic of the decay modes. The positron emitters, of short life mean Cu-62 (9.1 min, {beta}{sup +}) and Cu(12.7 h), are radionuclides applied in radio pharmacological preparation for brain, core, blood flux studies. The radiochemical process consists in the de solution of the irradiated metallic copper target, in acid medium. The result solution, can be neutralized with a base or a buffer at wished pH. Using a deuteron beam of 4,2 {+-} 0,1 MeV energy has been obtained total yields of 1,103 {+-} 0,011 {mu}Cl/{mu}Ah medium for 62 Cu and of 0,148 {+-} 0,015 {mu}Cl/{mu}Ah for 64 Cu.

Magnetic properties and low-temperature large magnetocaloric effect in the antiferromagnetic HoCu{sub 0.33}Ge{sub 2} and ErCu{sub 0.25}Ge{sub 2} compounds

Energy Technology Data Exchange (ETDEWEB)

Gao, R.L. [School of Metallurgy and Materials Engineering, Chongqing University of Science and Technology, Chongqing 401331 (China); Xu, Z.Y., E-mail: zhyxu@nim.ac.cn [National Institute of Metrology, Beijing 100029 (China); Wang, L.C. [State Key Laboratory for Magnetism, Institute of Physics, Chinese Academy of Sciences, Beijing 100190 (China); Dong, Q.Y.; Zhang, Y. [Department of Physics, Capital Normal University, Beijing 100048 (China); Liu, F.H. [National Space Science Center, Beijing 100190 (China); Mo, Z.J. [School of material Science and Engineering, Hebei University of Technology, Tianjin 300401 (China); Niu, E. [State Key Laboratory for Magnetism, Institute of Physics, Chinese Academy of Sciences, Beijing 100190 (China); Fu, C.L.; Cai, W.; Chen, G.; Deng, X.L. [School of Metallurgy and Materials Engineering, Chongqing University of Science and Technology, Chongqing 401331 (China)

2015-05-15

Highlights: • Antiferromagnetic material RCu{sub x}Ge{sub 2} of high purity was prepared. • Large MCE as −10.2 J/kg K and −10.5 J/kg K for RCu{sub x}Ge{sub 2} (Ho, Er) was obtained for field change of 0–50 kOe. • The RCu{sub x}Ge{sub 2} compounds with variable x had different transition temperature which made them suitable for ‘table-like’ magnetocaloric refrigerant. - Abstract: Magnetic properties and magnetocaloric effect (MCE) of HoCu{sub 0.33}Ge{sub 2} and ErCu{sub 0.25}Ge{sub 2} compounds have been investigated. The compounds were determined to be antiferromagnetic with the Néel temperatures T{sub N} = 9 K and 3.9 K, respectively. The critical transition magnetic fields for the metamagnetic transition from antiferromagnetic to ferromagnetic state below T{sub N} were determined to be 10 kOe for HoCu{sub 0.33}Ge{sub 2} at 5 K and 6 kOe for ErCu{sub 0.25}Ge{sub 2} at 2 K. Large MCE with the maximal values of magnetic entropy changes (ΔS{sub M}) as −10.2 J/kg K at 10.5 K were found in HoCu{sub 0.33}Ge{sub 2} for field changes of 0–70 kOe and −10.5 J/kg K at 5.5 K in ErCu{sub 0.25}Ge{sub 2} for field changes of 0–50 kOe, respectively. The large ΔS{sub M} around T{sub N} as well as no hysteresis loss made RCu{sub x}Ge{sub 2} competitive candidates as low temperature magnetic refrigerant.

EPR Study of [Cu(Him)4]·2Br Complex

International Nuclear Information System (INIS)

Yıldırım, İ; Karabulut, B

2016-01-01

The single crystal of [Cu(Him) 4 ]·2Br (Him: C 3 H 4 N 2 , imidazole) complex has been investigated at ambient temperature in three mutually perpendicular planes by EPR technique. The magnetic environments of [Cu(Him) 4 ]·2Br complex have been identified by EPR technique. The study reveals the existence of two magnetically inequivalent Cu 2+ sites. The principal values of g tensors were obtained. The EPR parameters show that the paramagnetic centers have rhombic symmetry. (paper)

Structural properties of hypothetical CeBa2Cu3O7 compound from LSDA+DMFT calculations

Directory of Open Access Journals (Sweden)

Łuszczek Maciej

2016-09-01

Full Text Available The hypothetical stoichiometric CeBa2Cu3O7 (Ce123 compound, which has not been synthesized as a single phase yet, was studied by the density functional theory (DFT. We utilized a method which merges the local spin density approximation (LSDA with the dynamical mean-field theory (DMFT to account for the electronic correlations. The LSDA+DMFT calculations were performed in the high-temperature range. The particular emphasis was put on the pressure-induced changes in the electronic band structure related to strongly correlated 4f states. The computational results indicate the occurrence of a large negative volumetric thermal expansion coefficient near T = 500 K and a trace of a low-volume isostructural metastable state at high temperatures.

Magnetic phase transition in layered inorganic-organic hybrid (C12H25NH3)2CuCl4

Science.gov (United States)

Bochalya, Madhu; Kumar, Sunil; Kanaujia, Pawan K.; Prakash, G. Vijaya

2018-05-01

Inorganic-organic (IO) hybrids are material systems which have become an interesting theme of research for physicist and chemists recently due to the possibility of engineering specific magnetic, thermal or optoelectronic properties by playing around with the transition metal, halides and the organic components. Our experiments on (C12H25NH3)2CuCl4 show that the system exhibits a long range ferromagnetic order below ˜11 K. In such an inorganic-organic hybrid system, Jahn-Teller distortion of the copper ions results into a weak ferromagnetic order as compared to the antiferromagnetic spin-spin exchange in the pure inorganic CuCl2 compound. Moreover, this particular hybrid system also exhibits photoluminescence when excited below absorption maximum related to charge transfer peak though the effect is much weaker as compared to that in extensively studied other MX4-based (M = Sn, Pb; X = Cl, Br, I) counterparts.

X-ray absorption spectroscopy on high-temperature superconductors and related compounds

International Nuclear Information System (INIS)

Pellegrin, E.J.H.A.

1995-07-01

The electronic structure of the cuprate high-temperature superconductors La 2-x Sr x CuO 4+δ , Tl 2 Ba 2 CaCu 2 O 8 and Tl 2 Ba 2 Ca 2 Cu 3 O 10 has been investigated using polarization-dependent near-edge X-ray absorption fine structure spectroscopy (NEXAFS). In addition, La 2-x Sr x NiO 4+δ has been included in the actual study as an isostructural analogue to the La 2-x Sr x CuO 4+δ system. It appears that the electronic structure of these compounds corresponds to that of a p-type doped charge-transfer insulator including electron-electron interactions on the Cu(Ni) sites and a strong hybridization between Cu(Ni) and O atoms. It is concluded that the low-energy excitations in these compounds can be described on the basis of an effective one-band Mott-Hubbard model. The polarization-dependence of the above spectra gives evidence for the strong in-plane character of the intrinsic and the doped holes. The small amount and the doping-dependence of the out-of-plane character of these charge carriers rule out models for a microscopic mechanism of superconductivity based on a large amount of hole states in the corresponding Apex-O2p z /Cu3d 3z 2 -r 2 orbitals. On the other hand, the reduction of this anisotropy in the overdoped compounds together with similar findings in the macroscopic properties seems to indicate a detrimental influence of non-planar orbitals on the superconducting properties. The differences in the energetic ordering and atomic character of the states close to the Fermi level between the undoped compounds La 2 CuO 4+δ , La 2 NiO 4+δ , and NiO have been determined from the NEXAFS data. It is found that these differences can be explained by the different size of the tetragonal crystal field splitting E Z compared to that of the Hund's rule interaction J H in these systems. This gives evidence for the high-spin d 8 ground state of the undoped nickelates (i.e. J H >E Z ). It is suggested that the polarons in La 2-x Sr x NiO 4+δ can be seen as non

Phase equilibria and crystalline structure of compounds in the Lu-Al and Lu-Cu-Al systems

International Nuclear Information System (INIS)

Kuz'ma, Yu.B.; Stel'makhovich, B.M.; Galamushka, L.I.

1992-01-01

Phase equilibria and crystal structure of compounds in Lu-Al and Lu-Cu-Al systems were studied. Existence of Lu 2 Al compound having the structure of the PbCl 2 type is ascertained. Diagram of phase equilibria of Lu-Cu-Al system at 870 K is plotted. Compounds Lu 2 (Cu,Al) 17 (the Th 2 Zn 17 type structure), Lu(Cu,Al) 5 (CaCu 5 type structure), Lu 6 (Cu,Al) 23 (Th 6 Mn 23 type structure) and ∼ LuCuAl 2 have been prepared for the first time. Investigation of component interaction in Lu-Cu-Al system shows that the system is similar to previously studied systems Dy-Cu-Al and Er-Cu-Al. The main difference consists in the absence of LuCuAl 3 compound with rhombic structure of the CeNi 2+x Sb 2-x type in the system investigated

COPPER RESISTANT STRAIN CANDIDA TROPICALIS RomCu5 INTERACTION WITH SOLUBLE AND INSOLUBLE COPPER COMPOUNDS

Directory of Open Access Journals (Sweden)

Ie. P. Prekrasna

2015-10-01

Full Text Available The focus of the study was interaction of Candida tropicalis RomCu5 isolated from highland Ecuador ecosystem with soluble and insoluble copper compounds. Strain C. tropicalis RomCu5 was cultured in a liquid medium of Hiss in the presence of soluble (copper citrate and CuCl2 and insoluble (CuO and CuCO3 copper compounds. The biomass growth was determined by change in optical density of culture liquid, composition of the gas phase was measured on gas chromatograph, redox potential and pH of the culture fluid was defined potentiometrically. The concentration of soluble copper compounds was determined colorimetrically. Maximal permissible concentration of Cu2+ for C. tropicalis RomCu5 was 30 000 ppm of Cu2+ in form of copper citrate and 500 ppm of Cu2+ in form of CuCl2. C. tropicalis was metabolically active at super high concentrations of Cu2+, despite the inhibitory effect of Cu2+. C. tropicalis immobilized Cu2+ in the form of copper citrate and CuCl2 by it accumulation in the biomass. Due to medium acidification C. tropicalis dissolved CuO and CuCO3. High resistance of C. tropicalis to Cu2+ and ability to interact with soluble and insoluble copper compounds makes it biotechnologically perspective.

First-principles study of electronic structure of CuSbS{sub 2} and CuSbSe{sub 2} photovoltaic semiconductors

Energy Technology Data Exchange (ETDEWEB)

Maeda, T., E-mail: tmaeda@ad.ryukoku.ac.jp; Wada, T.

2015-05-01

We studied the features of CuSbS{sub 2} (CAS) and CuSbSe{sub 2} (CASe), two proposed photovoltaic compounds, and clarified their electronic structures by first-principles calculations and compared them to the chalcopyrite-type CuInSe{sub 2} results. For both CAS and CASe, the calculated enthalpies of formation of the chalcostibite phases were considerably lower than those of the chalcopyrite phases. Therefore, we considered that the chalcostibite phase is more stable for CAS and CASe. In their band structure calculated with the HSE06 hybrid functional, the valence band maxima of CAS and CASe were located at the Γ-point, and the conduction band minima were located at the R-point. Their second lowest conduction band was located at the Γ-point, whose energy level nearly equaled the R-point. For CAS (CASe), the partial density of the states shows the character of the Cu 3d and S 3p (Se 4p) orbitals at the top of the valence bands and the Sb 5p and S 3p (Se 4p) orbitals at the bottom of the conduction bands. The conduction bands of CAS and CASe have a p-orbital character (Sb 5p) that differs from the s-orbital character (In 5s) of CuInSe{sub 2}. It is for the reason that CAS and CASe do not have a chalcopyrite structure but a chalcostibite-type structure. The calculated absorption coefficient of CuSbS{sub 2} (10{sup 4}-10{sup 5} cm{sup −1}) is comparable to that of CuInSe{sub 2}. - Highlights: • We studied the features of CuSbS{sub 2} and CuSbSe{sub 2}, newly proposed photovoltaic compounds. • Chalcostibite phase is more stable in CuSbS{sub 2} and CuSbSe{sub 2}. • Band structures of CuSbS{sub 2} and CuSbS{sub 2} were calculated with HSE06 hybrid functional. • Absorption coefficient of chalcostibite-type CuSbS{sub 2} is comparable to that of CuInSe{sub 2}.

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

Energy Technology Data Exchange (ETDEWEB)

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

2016-08-15

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

(1-Butyl-4-methyl-pyridinium)[Cu(SCN)2]: a coordination polymer and ionic liquid.

Science.gov (United States)

Spielberg, Eike T; Edengeiser, Eugen; Mallick, Bert; Havenith, Martina; Mudring, Anja-Verena

2014-04-25

The compound (C4C1py)[Cu(SCN)2], (C4C1py = 1-Butyl-4-methyl-pyridinium), which can be obtained from CuSCN and the ionic liquid (C4C1py)(SCN), turns out to be a new organic-inorganic hybrid material as it qualifies both, as a coordination polymer and an ionic liquid. It features linked [Cu(SCN)2](-) units, in which the thiocyanates bridge the copper ions in a μ1,3-fashion. The resulting one-dimensional chains run along the a axis, separated by the C4C1py counterions. Powder X-ray diffraction not only confirms the single-crystal X-ray structure solution but proves the reformation of the coordination polymer from an isotropic melt. However, the materials shows a complex thermal behavior often encountered for ionic liquids such as a strong tendency to form a supercooled melt. At a relatively high cooling rate, glass formation is observed. When heating this melt in differential scanning calorimetry (DSC) and temperature-dependent polarizing optical microscopy (POM), investigations reveal the existence of a less thermodynamically stable crystalline polymorph. Raman measurements conducted at 10 and 100 °C point towards the formation of polyanionic chain fragments in the melt. Solid-state UV/Vis spectroscopy shows a broad absorption band around 18,870 cm(-1) (530 nm) and another strong one below 20,000 cm(-1) (<500 nm). The latter is attributed to the d(Cu(I))→π*(SCN)-MLCT (metal-to-ligand charge transfer) transition within the coordination polymer yielding an energy gap of 2.4 eV. At room temperature and upon irradiation with UV light, the material shows a weak fluorescence band at 15,870 cm(-1) (630 nm) with a quantum efficiency of 0.90(2) % and a lifetime of 131(2) ns. Upon lowering the temperature, the luminescence intensity strongly increases. Simultaneously, the band around 450 nm in the excitation spectrum decreases. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Synthesis of highly non-stoichiometric Cu{sub 2}ZnSnS{sub 4} nanoparticles with tunable bandgaps

Energy Technology Data Exchange (ETDEWEB)

Hamanaka, Yasushi, E-mail: hamanaka@nitech.ac.jp; Oyaizu, Wataru; Kawase, Masanari [Nagoya Institute of Technology, Department of Materials Science and Engineering (Japan); Kuzuya, Toshihiro [Muroran Institute of Technology, College of Design and Manufacturing Technology (Japan)

2017-01-15

Non-stoichiometric Cu{sub 2}ZnSnS{sub 4} nanoparticles with average diameters of 4–15 nm and quasi-polyhedral shape were successfully synthesized by a colloidal method. We found that a non-stoichiometric composition of Zn to Cu in Cu{sub 2}ZnSnS{sub 4} nanoparticles yielded a correlation where Zn content increased with a decrease in Cu content, suggesting formation of lattice defects relating to Cu and Zn, such as a Cu vacancy (V{sub Cu}), antisite with Zn replacing Cu (Zn{sub Cu}), and/or defect cluster of V{sub Cu} and Zn{sub Cu}. The bandgap energy of Cu{sub 2}ZnSnS{sub 4} nanoparticles systematically varies between 1.56 and 1.83 eV depending on the composition ratios of Cu and Zn, resulting in a wider bandgap for Cu-deficient Cu{sub 2}ZnSnS{sub 4} nanoparticles. These characteristics can be ascribed to the modification in electronic band structures due to formation of V{sub Cu} and Zn{sub Cu} on the analogy of ternary copper chalcogenide, chalcopyrite CuInSe{sub 2}, in which the top of the valence band shifts downward with decreasing Cu contents, because much like the structure of CuInSe{sub 2}, the top of the valence band is composed of a Cu 3d orbital in Cu{sub 2}ZnSnS{sub 4}.

Copper(II) complexes with 4-(1H-1, 2, 4-trizol-1-ylmethyl) benzoic acid: Syntheses, crystal structures and antifungal activities

International Nuclear Information System (INIS)

Xiong, Pingping; Li, Jie; Bu, Huaiyu; Wei, Qing; Zhang, Ruolin; Chen, Sanping

2014-01-01

Reaction of Cu(II) with an asymmetric semi-rigid organic ligand 4-(1H-1, 2, 4-trizol-1-ylmethyl) benzoic acid (HL), yielded five compounds, [Cu 0.5 L] n (1), [Cu(HL) 2 Cl 2 ] n (2), [Cu(HL) 2 Cl 2 (H 2 O)] (3), [Cu(L) 2 (H 2 O)] n (4) and [Cu(L)(phen)(HCO 2 )] n (5), which have been fully characterized by infrared spectroscopy, elemental analysis, and single-crystal X-ray diffraction. As for compounds 1, 2 and 5, Cu(II) is bridged through HL, Cl - , and formic acid, respectively, featuring 1D chain-structure. In compound 3, Cu(II) with hexahedral coordination sphere is assembled through hydrogen-bonding into 3D supramolecular framework. In compound 4, 1D chain units –Cu–O–Cu–O– are ligand-bridged into a 3D network. All compounds were tested on fungi (Fusarium graminearum, Altemaria solani, Macrophoma kawatsukai, Alternaria alternata and Colletotrichum gloeosporioides). Compound 1 exhibits a better antifungal effect compared to other compounds. An effect of structure on the antifungal activity has also been correlated. - Graphical abstract: Copper(II) compounds with 4-(1H-1, 2, 4-trizol-1-ylmethyl) benzoic acid, were prepared, structurally characterized and investigated for antifungal activity. - Highlights: • The title compounds formed by thermodynamics and thermokinetics. • The five compounds show higher inhibition percentage than reactants. • The structure effect on the antifungal activity

Structural, dielectric and magnetic properties of SnO{sub 2}-CuFe{sub 2}O{sub 4} nanocomposites

Energy Technology Data Exchange (ETDEWEB)

Ali, Kashif [Department of Physics, International Islamic University, Islamabad (Pakistan); Iqbal, Javed, E-mail: javed.saggu@qau.edu.pk [Laboratory of Nanoscience and Technology (LNT), Department of Physics, Qaid-i-Azam University, Islamabad (Pakistan); Jan, Tariq [Department of Physics, University of Lahore, Sargodha Campus, Sargodha (Pakistan); Wan, Dongyun [School of Materials Science and Engineering, Shanghai University, Shanghai 200444 (China); Ahmad, Naeem [Department of Physics, International Islamic University, Islamabad (Pakistan); Ahamd, Ishaq [Experimental Physics Labs, National Center for Physics, Islamabad (Pakistan); Ilyas, Syed Zafar [Department of Physics, Allama Iqbal Open University, Islamabad (Pakistan)

2017-04-15

The nanocomposites of (SnO{sub 2}){sub x}(CuFe{sub 2}O{sub 4}){sub (1−x)} (where x=0–100 wt%) have been successfully synthesized via two steps chemical method. XRD pattern has revealed the formation of inverse spinal phases with tetragonal crystal structure without any impurity phases for CuFe{sub 2}O{sub 4} sample. The thermodynamic solubility limit of SnO{sub 2} in CuFe{sub 2}O{sub 4} matrix has been found to be 30 wt% and above this percentage crystal phases related to SnO{sub 2} started to appear. The average particle size and shape of CuFe{sub 2}O{sub 4} nanoparticles have been strongly influenced by addition of SnO{sub 2} as depicted by TEM results. FTIR results have confirmed the existence of cation vibration bands at tetrahedral and octahedral sites along with Sn-O vibration band at higher concentrations, which also validates the formation of nanocomposites. Furthermore, the dielectric constant, tangent loss and conductivity of CuFe{sub 2}O{sub 4} nanoparticles have been found to increase up to 30 wt% addition of SnO{sub 2} and then decreases with further increase which is attributed to variations in resistivity and space charge carriers. Magnetic measurements have shown that saturation magnetization decreases from 35.68 emu/gm to 10.26 emu/gm with the addition of SnO{sub 2} content. - Highlights: • SnO{sub 2}-CuFe{sub 2}O{sub 4} nanocomposites with varying SnO{sub 2} concentrations were synthesized. • The thermodynamic solubility limit for SnO{sub 2} into CuFe{sub 2}O{sub 4} matrix by employing current method was found to be ≤30 wt%. • At higher concentrations, structural phases related to SnO{sub 2} started to appear. • FTIR results corroborated well with the XRD results. • It has been observed that the addition of SnO{sub 2} significantly influence the morphology, dielectric and magnetic properties of CuFe{sub 2}O{sub 4} nanoparticles.

Characterization of Cu(In,Ga)(S,Se)2 thin films prepared by sequential evaporation from ternary compounds

International Nuclear Information System (INIS)

Yamaguchi, T.; Hatori, M.; Niiyama, S.; Miyake, Y.

2006-01-01

Cu(In,Ga)(S,Se) 2 thin films were fabricated by sequential evaporation from CuGaSe 2 , CuInSe 2 and In 2 S 3 compounds for photovoltaic device applications. From XRF analysis, the Cu:(In+Ga):(S+Se) atomic ratio in all thin films was approximately 1:1:2. As the [In 2 S 3 ]/([CuGaSe 2 ]+[CuInSe 2 ]) mole ratio in the evaporating materials increased, the S/(S+Se) atomic ratio in the thin films increased from 0 to 0.16 determined by XRF and to 0.43 by EPMA. XRD studies demonstrated that the prepared thin films had a chalcopyrite Cu(In,Ga) (S,Se) 2 structure and the preferred orientation to the 112 plane. The SEM images demonstrated that Cu(In,Ga)(S,Se) 2 thin films had large and columnar grains. (copyright 2006 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (Abstract Copyright [2006], Wiley Periodicals, Inc.)

Structural studies of type N superconductive compounds: R2-xCexCuO4±δ (R = Gd, Eu, Sm, Nd, Pr); influences of chemical treatments on physical properties

International Nuclear Information System (INIS)

Vigoureux, P.

1995-06-01

Different chemical treatments of R 2-x Ce x CuO 4±δ compounds monocrystals (gadolinium, europium, samarium, neodymium and praseodymium cuprates) modify their physical properties especially their superconductive properties. The presented chemical treatments are: the substitution of the trivalent rare earth element R by an other trivalent lanthanide, its substitution by tetravalent cerium, and heat treatment under low oxygen pressure. After these chemical treatments, structural modifications are observed by neutrons and X-rays diffraction, and allow to precise their actions: size effect of the rare earth element on the deformation of the CuO 2 planes, links between deformation and superconductivity and magnetic properties. (A.B.)

Ternary CaCu4P2-type pnictides AAg4Pn2 (A=Sr, Eu; Pn=As, Sb)

International Nuclear Information System (INIS)

Stoyko, Stanislav S.; Khatun, Mansura; Scott Mullen, C.; Mar, Arthur

2012-01-01

Four ternary pnictides AAg 4 Pn 2 (A=Sr, Eu; Pn=As, Sb) were prepared by reactions of the elements at 850 °C and their crystal structures were determined from single-crystal X-ray diffraction studies. These silver-containing pnictides AAg 4 Pn 2 adopt the trigonal CaCu 4 P 2 -type structure (Pearson symbol hR21, space group R3-bar m, Z=3; a=4.5555(6) Å, c=24.041(3) Å for SrAg 4 As 2 ; a=4.5352(2) Å, c=23.7221(11) Å for EuAg 4 As 2 ; a=4.7404(4) Å, c=25.029(2) Å for SrAg 4 Sb 2 ; a=4.7239(3) Å, c=24.689(2) Å for EuAg 4 Sb 2 ), which can be derived from the trigonal CaAl 2 Si 2 -type structure of the isoelectronic zinc-containing pnictides AZn 2 Pn 2 by insertion of additional Ag atoms into trigonal planar sites within [M 2 Pn 2 ] 2− slabs built up of edge-sharing tetrahedra. Band structure calculations on SrAg 4 As 2 and SrAg 4 Sb 2 revealed that these charge-balanced Zintl phases actually exhibit no gap at the Fermi level and are predicted to be semimetals. - Graphical abstract: SrAg 4 As 2 and related pnictides adopt a CaCu 4 P 2 -type structure in which additional Ag atoms enter trigonal planar sites within slabs built from edge-sharing tetrahedra. Highlights: ► AAg 4 Pn 2 are the first Ag-containing members of the CaCu 4 P 2 -type structure. ► Ag atoms are stuffed in trigonal planar sites within CaAl 2 Si 2 -type slabs. ► Ag–Ag bonding develops through attractive d 10 –d 10 interactions.

Electronic structures of PrBa{sub 2}Cu{sub 3}O{sub 7}, Pr{sub 2}Ba{sub 4}Cu{sub 7}O{sub 15-y}(y=0,1), and PrBa{sub 2}Cu{sub 4}O{sub 8} based on LSDA+U method

Energy Technology Data Exchange (ETDEWEB)

Tavana, A. [Magnet Research Laboratory (MRL), Department of Physics, Sharif University of Technology, Tehran (Iran); Department of Physics, University of Mohaghegh Ardabili, Ardabil (Iran); Shirazi, M.; Akhavan, M. [Magnet Research Laboratory (MRL), Department of Physics, Sharif University of Technology, Tehran (Iran)

2009-10-15

The electronic structures of PrBa{sub 2}Cu{sub 3}O{sub 7} (Pr123), Pr{sub 2}Ba{sub 4}Cu{sub 7}O{sub 15-y} (Pr247), and PrBa{sub 2}Cu{sub 4}O{sub 8} (Pr124) cuprates have been obtained using density-functional theory in the local spin density approximation plus onsite Coulomb interaction (LSDA+U). Onsite Hubbard correlation, U, has been considered for Pr-f and Cu-d orbitals and the effects of considering these correlation corrections on the Pr-O hybridizations have been inspected. Results imply that the Pr ionization state in Pr123 system is constituted from two different configurations, and the energy of the f states in these two configurations has an important role in superconductivity properties of the system. Our calculations also show that in both Pr124 and Pr247 systems, suppression of superconductivity is weaker than that in the Pr123 system. This occurs due to the weaker Pr-O bond in both Pr124 and Pr247 systems. The role of the double chain and single chain on the conduction properties of these compounds has been investigated. We have also studied the effect of oxygen deficiency in Pr247 system, which seems to revive superconductivity in this system. Investigating the hole carriers in the CuO{sub 2} plane shows a correlation between superconductivity suppression and hole decrement in the planes. (Abstract Copyright [2009], Wiley Periodicals, Inc.)

Cu-62, Cu-64 and Cu-66 production with 4.2 MeV deuterons

International Nuclear Information System (INIS)

Avila, Mario; Morales, J.R.; Riquelme, H.O.

1996-01-01

Full text: The natural copper irradiation with deuterons produces the Cu-62, Cu-64 and Cu-66 radionuclides. Of two radioisotopes, those with deficiencies in neutrons, are applied in nuclear medicine diagnostic processes, mainly for the nuclear characteristic of the decay modes. The positron emitters, of short life mean Cu-62 (9.1 min, β + ) and Cu(12.7 h), are radionuclides applied in radio pharmacological preparation for brain, core, blood flux studies. The radiochemical process consists in the de solution of the irradiated metallic copper target, in acid medium. The result solution, can be neutralized with a base or a buffer at wished pH. Using a deuteron beam of 4,2 ± 0,1 MeV energy has been obtained total yields of 1,103 ± 0,011 μCl/μAh medium for 62 Cu and of 0,148 ± 0,015 μCl/μAh for 64 Cu

Crystal Growth and Neutron Scattering Study of Spin Correlations of the T‧-Structured Pr2‑x Ca x CuO4

Science.gov (United States)

Fujita, Masaki; Tsutsumi, Kenji; Miura, Tomohiro; Danilkin, Sergey

2018-03-01

We studied Ca-doping effect on spin correlations in T‧-structured cuprate oxide RE2CuO4 (RE: rear earth) with growing a sizable single crystal of Pr2‑x Ca x CuO4 (x=0.05 and 0.10) as well as synthesizing powder samples of Pr1.90Ca0.10CuO4 and Eu1.90Ca0.10CuO4. In the all as-prepared and annealed samples, no evidence of shielding signal associated with superconductivity was observed by magnetic susceptibility measurement. Elastic neutron scattering measurements on the as-grown Pr1.90Ca0.10CuO4 clarified the existence of long-ranged magnetic order with commensurate spin correlation. The ordering temperature was determined to be ∼290K, which is comparable to Néel temperature in the parent compound of Pr2CuO4. The existence of commensurate low-energy spin excitation was also confirmed by inelastic neutron scattering measurements for the annealed Pr1.95Ca0.05CuO4. These results strongly suggest a negligible Ca-doping effect on the physical properties in T‧-RE2CuO4, which is quite different from the drastic doping evolution of magnetism in T -RE2CuO4.

Microscopic studies on Y2Ba4Cu7O15-δ by use of TEM and NQR techniques

International Nuclear Information System (INIS)

Kato, Masaki; Nakanishi, Makoto; Yoshimura, Kazuyoshi; Kosuge, Koji; Miyano, Toshio; Kakihana, Masato

1998-01-01

Y 2 Ba 4 Cu 7 O 15-δ compounds were characterized by microscopic investigation using TEM and NQR techniques. The authors synthesized Y247 compounds by two kinds of preparation methods: the conventional solid-state reaction (sample A) and the polymerized-complex method (sample B). The value of T c for sample A was found o be 65 K and that for sample B as 93 K by ac-χ measurements. As a result of TEM experiments, stacking faults along the c axis were observed more frequently in sample B than in sample A. These stacking faults resulted in microdomains containing pure Y123 or Y124 thin blocks of several unit cells. NQR experiments revealed that the microscopic environment of Cu(2) sites in sample A differed from either of those in the Y123 and Y124 compounds. NQR frequency values (ν Q ) of Cu(2) sites agreed well with those calculated by the point charge model applied for the Y247 structure. The spectra of Cu(2) sites in sample B could be regarded, however, as a combination of those of pure Y123, Y124, and also Y247 compounds. This fact was coincident with the result of TEM experiments. The authors concluded that the superconductivity of Y247 with higher T c originates from the thin block of Y123

The TolC protein of Legionella pneumophila plays a major role in multi-drug resistance and the early steps of host invasion.

Directory of Open Access Journals (Sweden)

Mourad Ferhat

Full Text Available Pneumonia associated with Iegionnaires's disease is initiated in humans after inhalation of contaminated aerosols. In the environment, Legionella pneumophila is thought to survive and multiply as an intracellular parasite within free-living amoeba. In the genome of L. pneumophila Lens, we identified a unique gene, tolC, encoding a protein that is highly homologous to the outer membrane protein TolC of Escherichia coli. Deletion of tolC by allelic exchange in L. pneumophila caused increased sensitivity to various drugs. The complementation of the tolC mutation in trans restored drug resistance, indicating that TolC is involved in multi-drug efflux machinery. In addition, deletion of tolC caused a significant attenuation of virulence towards both amoebae and macrophages. Thus, the TolC protein appears to play a crucial role in virulence which could be mediated by its involvement in efflux pump mechanisms. These findings will be helpful in unraveling the pathogenic mechanisms of L. pneumophila as well as in developing new therapeutic agents affecting the efflux of toxic compounds.

NQR study in superconducting La2CuO4+δ

International Nuclear Information System (INIS)

Ueda, K.; Sugata, T.; Kohori, Y.; Oda, Y.; Kohara, T.

1992-01-01

Cu NQR signals were observed around 33.1 and 36.0 MHz together with the antiferromagnetic Cu NMR signals in the superconducting La 2 CuO 4+ δ obtained by annealing in high pressure oxygen gas. The NQR intensity increases with increasing oxygen contents. The nuclear spin-lattice relaxation time, T 1 , of Cu NQR indicates that the paramagnetic phase is in the superconducting state at low temperatures. These results show that the NQR and NMR signals were coming from the Cu sites in the superconducting phase and the antiferromagnetic phase, respectively. No appreciable differences were observed in the Cu NQR spectrum and the relaxation time between the superconducting La 2 CuO 4 + δ samples annealed under the oxygen pressure of 400 ≅ 1200 bar. (orig.)

Neutron scattering studies on phase transitions in (CD3ND3)2CuCl4 and MnCl2.4H2O

International Nuclear Information System (INIS)

Steijger, J.J.M.

1982-10-01

In this thesis the results of neutron scattering experiments and measurements of the susceptibility on some compounds which display magnetic and/or structural phase transitions, are described. Following an introductory chapter, chapter 2 shows that neutron scattering can be used as a tool for unravelling problems in crystallographic and magnetic structure. The qualitative different scattering patterns for scatters are described. In chapters 3 and 4 an investigation on the layered ferromagnets (CH 3 NH 3 ) 2 CuCl 4 and (CD 3 ND 3 ) 2 CuCl 4 is described. In these materials the copper ions, which carry the magnetic moment, are more closely spaced in the ab-planes, and consequently the magnetic interactions in these planes are stronger than those in the direction perpendicular to these planes by about a factor of 10 5 . Chapter 5 presents a discussion and a calculation of demagnetizing and dipole fields. The second part of this thesis is concerned with the transition from the antiferromagnetic to the paramagnetic phase in MnCl 2 .4H 2 O in the presence of a magnetic field applied perpendicular to the preferred direction of the magnetic moments. The theory is reviewed in chapter 6 and in chapter 7 the correction procedure for inhomogeneous internal fields is applied to the measurements on MnCl 2 .4H 2 O. (Auth./C.F.)

Critical current density of four-CuO2-layer T1Ba2Ca3Cu4O11-δ

International Nuclear Information System (INIS)

Zhang, L.; Liu, J.Z.; Shelton, R.N.

1998-01-01

Full text: A key requirement for technological application is to have superconductors with high critical current density at practical operating temperatures and magnetic fields. The critical current density is strongly related to underlying properties of high T c superconductors, such as layering, anisotropy and other intrinsic material structures. The thallium-based superconductors attracted much attention at early stage mainly due to their high superconducting transitions. Recent studies show that these materials appear to be a better choice for achieving higher critical current density because of a stronger interlayer coupling between superconducting layers. Single crystals of TlBa 2 Ca 3 Cu 4 O 11-δ were grown by a self-flux method. This material is a strong-layered superconductor with four-CuO 2 -planes in a unit cell and a superconducting transition temperature of 128K. Our experimental results show that TlBa 2 Ca 3 Cu 4 O 11-δ crystals have high irreversibility line, large critical current density and high upper critical field. The impact of layering and the number of Cu-O layers on flux pinning, critical current density and other magnetic properties will also be discussed

Cu/Cu{sub 2}O/CuO loaded on the carbon layer derived from novel precursors with amazing catalytic performance

Energy Technology Data Exchange (ETDEWEB)

Zhao, Xiaoli, E-mail: zhaoxiaoli_zxl@126.com [State Key Laboratory of Environmental Criteria and Risk Assessment, Chinese Research Academy of Environmental Sciences, Beijing 100012 (China); Tan, Yixin [State Key Laboratory of Environmental Criteria and Risk Assessment, Chinese Research Academy of Environmental Sciences, Beijing 100012 (China); State Key Laboratory of Environmental Chemistry and Ecotoxicology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085 (China); Wu, Fengchang, E-mail: wu_fengchang@126.com [State Key Laboratory of Environmental Criteria and Risk Assessment, Chinese Research Academy of Environmental Sciences, Beijing 100012 (China); Niu, Hongyun [State Key Laboratory of Environmental Chemistry and Ecotoxicology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085 (China); Tang, Zhi [State Key Laboratory of Environmental Criteria and Risk Assessment, Chinese Research Academy of Environmental Sciences, Beijing 100012 (China); Cai, Yaqi [State Key Laboratory of Environmental Chemistry and Ecotoxicology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085 (China); Giesy, John P. [State Key Laboratory of Environmental Criteria and Risk Assessment, Chinese Research Academy of Environmental Sciences, Beijing 100012 (China); Department of Veterinary Biomedical Sciences and Toxicology Centre, University of Saskatchewan, Saskatoon, Saskatchewan (Canada)

2016-11-15

A simple, novel method for synthesis of Cu/Cu{sub 2}O/CuO on surfaces of carbon (Cu/Cu{sub 2}O/CuO@C) as a non-noble-metal catalyst for reduction of organic compounds is presented. Compared with noble metals, Cu/Cu{sub 2}O/CuO@C particles are more efficient and less expensive. Characterization of the Cu/Cu{sub 2}O/CuO@C composites by high-resolution transmission electron microscope (HRTEM), x-ray diffraction (XRD), infrared spectroscopy and Raman analysis, revealed that it was composed of graphitized carbon with numerous nanoparticles (100 nm in diameter) of Cu/CuO/Cu{sub 2}O that were uniformly distributed on internal and external surfaces of the carbon support. Gallic acid (GA) has been used as both organic ligand and carbon precursor with metal organic frameworks (MOFs) as the sacrificial template and metal oxide precursor in this green synthesis. The material combined the advantages of MOFs and Cu-containing materials, the porous structure provided a large contact area and channels for the pollutions, which results in more rapid catalytic degradation of pollutants and leads to greater efficiency of catalysis. The material gave excellent catalytic performance for organic dyes and phenols. In this study, Cu/Cu{sub 2}O/CuO@C was used as catalytic to reduce 4-NP, which has been usually adopted as a model reaction to check the catalytic ability. Catalytic experiment results show that 4-NP was degraded approximately 3 min by use of 0.04 mg of catalyst and the conversion of pollutants can reach more than 99%. The catalyst exhibited little change in efficacy after being utilized five times. Rates of degradation of dyes, such as Methylene blue (MB) and Rhodamine B (RhB) and phenolic compounds such as O-Nitrophenol (O-NP) and 2-Nitroaniline (2-NA) were all similar. - Highlights: • We present an effective catalyst for reductive degradation of organic dyes and phenols in water. • Compared with noble metals, Cu/Cu{sub 2}O/CuO@C particles are more efficient and less

LEACHABILITY OF CHROME FROM MAGNESIA-CHROMITE REFRACTORY BRICKS CORRODED BY Cu/CuO- Na2O.2SiO2 SLAGS

Directory of Open Access Journals (Sweden)

David Medved

2015-06-01

Full Text Available The interactions of magnesia-chromite refractory brick with Cu-Na2O.2SiO2 and CuO-Na2O.2SiO2 melts are studied and the chemical durability of corrosion products in water is evaluated. The corrosion tests confirm intensive infiltration of the slag melts into the tested refractory bricks and formation of Cr(6+ compounds. The molten copper partially oxidizes during corrosion test by air and penetrates into bricks. Interactions among periclase (MgO and chromite (FeCr2O4 grains with the melt Na2O.2SiO2 and copper oxides makes possible to form several compounds (e.g. Cu2MgO3, CuCrO4, CaCrO4, Na2CrO4, MgCrO4. Just the marked yellow spots, which were observed on the corroded brick surface after 30 days of free storage, suggest hydration of the high-temperature corrosion products. The yellow color of spots points out to chromates as Na2CrO4 and MgCrO4, which are well soluble in water. The leaching of corroded bricks in water (batch leaching test of a ratio of S (solid : W (water = 0.1 taking up to 28 days confirmed the Cr, Na, Mg and Ca ions leach-out. The pH value of solution increased up to 9 during leaching mainly as a consequence of elevated Na+ ion concentration. The Cr ion concentration rises in the solution up to 1 mmol.l-1. The observed moderate decrease of Cr ion concentration in the solution with the length of leaching indicates super-saturation of the solution and precipitation of the products.

Copper(II) complexes with 4-(1H-1, 2, 4-trizol-1-ylmethyl) benzoic acid: Syntheses, crystal structures and antifungal activities

Energy Technology Data Exchange (ETDEWEB)

Xiong, Pingping [Key Laboratory of Synthetic and Natural Functional Molecule Chemistry of Ministry of Education, College of Chemistry and Materials Science, Northwest University, Xi' an 710069 (China); Li, Jie [Key Laboratory of Resource Biology and Biotechnology in Western China (Ministry of Education), Shaanxi Provincial Key Laboratory of Biotechnology, Xi' an 710069 (China); Bu, Huaiyu, E-mail: 7213792@qq.com [Key Laboratory of Resource Biology and Biotechnology in Western China (Ministry of Education), Shaanxi Provincial Key Laboratory of Biotechnology, Xi' an 710069 (China); Wei, Qing [Key Laboratory of Synthetic and Natural Functional Molecule Chemistry of Ministry of Education, College of Chemistry and Materials Science, Northwest University, Xi' an 710069 (China); Zhang, Ruolin [Key Laboratory of Resource Biology and Biotechnology in Western China (Ministry of Education), Shaanxi Provincial Key Laboratory of Biotechnology, Xi' an 710069 (China); Chen, Sanping, E-mail: sanpingchen@126.com [Key Laboratory of Synthetic and Natural Functional Molecule Chemistry of Ministry of Education, College of Chemistry and Materials Science, Northwest University, Xi' an 710069 (China)

2014-07-01

Reaction of Cu(II) with an asymmetric semi-rigid organic ligand 4-(1H-1, 2, 4-trizol-1-ylmethyl) benzoic acid (HL), yielded five compounds, [Cu{sub 0.5}L]{sub n} (1), [Cu(HL){sub 2}Cl{sub 2}]{sub n} (2), [Cu(HL){sub 2}Cl{sub 2}(H{sub 2}O)] (3), [Cu(L){sub 2}(H{sub 2}O)]{sub n} (4) and [Cu(L)(phen)(HCO{sub 2})]{sub n} (5), which have been fully characterized by infrared spectroscopy, elemental analysis, and single-crystal X-ray diffraction. As for compounds 1, 2 and 5, Cu(II) is bridged through HL, Cl{sup -}, and formic acid, respectively, featuring 1D chain-structure. In compound 3, Cu(II) with hexahedral coordination sphere is assembled through hydrogen-bonding into 3D supramolecular framework. In compound 4, 1D chain units –Cu–O–Cu–O– are ligand-bridged into a 3D network. All compounds were tested on fungi (Fusarium graminearum, Altemaria solani, Macrophoma kawatsukai, Alternaria alternata and Colletotrichum gloeosporioides). Compound 1 exhibits a better antifungal effect compared to other compounds. An effect of structure on the antifungal activity has also been correlated. - Graphical abstract: Copper(II) compounds with 4-(1H-1, 2, 4-trizol-1-ylmethyl) benzoic acid, were prepared, structurally characterized and investigated for antifungal activity. - Highlights: • The title compounds formed by thermodynamics and thermokinetics. • The five compounds show higher inhibition percentage than reactants. • The structure effect on the antifungal activity.

Hydrothermal synthesis and structure of a novel 3D framework based on ξ-octamolybdate chains: [Cu2(quinoxaline)2Mo4O13]n

International Nuclear Information System (INIS)

Chen Lijuan; Lu Canzhong; He Xiang; Zhang Quanzheng; Yang Wenbin; Lin Xinhua

2006-01-01

An unprecedented three-dimensional (3D) polymer [Cu 2 (quinoxaline) 2 Mo 4 O 13 ] n , formed from ξ-octamolybdate chains as building units and pairs of 1D [Cu(quinoxaline)] n n+ polymeric chains as linkers, provides the first example of an extended higher dimensional structure based on [Mo 8 O 26 ] n 4n- octamolybdate chain. The basic building block of the octamolybdate chain included in the title compound is first reported to be constructed from ξ-isomer of octamolybdate unit

The corrosion behavior of the T1 (Al2CuLi) intermetallic compound in aqueous environments

Science.gov (United States)

Buchheit, R. G.; Stoner, G. E.

1989-01-01

The intermetallic compound T1 (Al2CuLi) is suspected to play an important role in the localized corrosion at subgrain boundaries in Al-Li-Cu alloys. The intermetallic was synthesized for characterization of its corrosion behavior. Experiments performed included open circuit potential measurements, potentiodynamic polarization, and corrosion rate vs. pH in solutions whose pH was varied over the range of 3 to 11. Subgrain boundary pitting and continuous subgrain boundary corrosion are discussed in terms of the data obtained. Evidence suggesting the dealloying of copper from this compound is also presented.

Subsolidus Phase Relations of the SrO-In2O3-CuO System in Air

DEFF Research Database (Denmark)

Grivel, Jean-Claude; Thydén, Karl Tor Sune

2013-01-01

The subsolidus phase relations of the SrO-In2O3-CuO system were investigated at 900 °C in air. Under these conditions, five binary oxide phases are stable: Sr2CuO3, SrCuO2, Sr14Cu24O41, In2Cu2O5 and SrIn2O4. The pseudo-ternary section is characterised by six three-phase regions and is dominated...

Structure and superconductivity of room temperature chemically oxidized La_2-xNd_xCuO_4+y (0<=x<=0.5)

DEFF Research Database (Denmark)

Rial, C.; Moran, E.; Alario-Franco, M.A.

1997-01-01

-doping increases, probably due to the progressive contraction of the structure along the c-axis. Analogies and differences in the modifications induced by the oxidation process in the present La2-xNdxCuO4+y materials and in related compounds La2-x(Ca/Sr/Ba)(x)CuO4+y (x less than or equal to 0.15) are reported...

Magnetism and superconductivity in Ru{sub 1-x}Sr{sub 2}RECu{sub 2+x}O{sub 8-d} (RE=Gd, Eu) and RuSr{sub 2}Gd{sub 1-y}Ce{sub y}Cu{sub 2}O{sub 8} compounds

Energy Technology Data Exchange (ETDEWEB)

Klamut, P.W. [Dept. of Physics, Northern Illinois Univ., DeKalb, IL (United States)]|[Inst. of Low Temperature and Structure Research of Polish Academy of Sciences, Wroclaw (Poland); Dabrowski, B.; Mini, S.M.; Kolesnik, S.; Maxwell, M.; Mais, J. [Dept. of Physics, Northern Illinois Univ., DeKalb, IL (United States); Shengelaya, A.; Keller, H. [Physik-Inst., Univ. Zuerich, Zuerich (Switzerland); Khazanov, R. [Physik-Inst., Univ. Zuerich, Zuerich (Switzerland)]|[Lab. for Muon-Spin Spectroscopy, Paul Scherrer Inst., Villigen PSI (Switzerland); Savic, I. [Physik-Inst., Univ. Zuerich, Zuerich (Switzerland)]|[Faculty of Physics, Univ. of Belgrade, Belgrade (Yugoslavia); Sulkowski, C.; Wlosewicz, D.; Matusiak, M. [Inst. of Low Temperature and Structure Research of Polish Academy of Sciences, Wroclaw (Poland); Wisniewski, A.; Puzniak, R.; Fita, I. [Inst. of Physics of Polish Academy of Sciences, Warszawa (Poland)

2002-07-01

We discuss the properties of new superconducting compositions of ruthenocuprates Ru{sub 1-x}Sr{sub 2}RECu{sub 2+x}O{sub 8-d} (RE=Gd, Eu) that were synthesized at 600 atm. of oxygen at 1080 C. By changing ratio between the Ru and Cu, the temperature of superconducting transition (T{sub C}) raises up to T{sub C}{sup max} = 72 K for x=0.3, 0.4. The hole doping achieved along the series increases with Cu{yields}Ru substitution. For x {ne} 0, T{sub C} can be subsequently tuned between T{sub C}{sup max} and 0 K by changing oxygen content in the compounds. The magnetic characteristics of the RE=Gd and Eu based compounds are interpreted as indicative of constrained dimensionality of the superconducting phase. Muon spin rotation experiments reveal the presence of the magnetic transitions at low temperatures (T{sub m}=14-2 K for x=0.1-0.4) that can originate in the response of Ru/Cu sublattice. RuSr{sub 2}Gd{sub 1-y}Ce{sub 1-y}Cu{sub 2}O{sub 8} (0 {<=} y {<=} 0.1) compounds show the simultaneous increase of T{sub N} and decrease of T{sub C} with y. The effect should be explained by the electron doping that occurs with Ce{yields}Gd substitution. Properties of these two series allow us to propose phase diagram for 1212-type ruthenocuprates that links their properties to the hole doping achieved in the systems. Non-superconducting single-phase RuSr{sub 2}GdCu{sub 2}O{sub 8} and RuSr{sub 2}EuCu{sub 2}O{sub 8} are reported and discussed in the context of the properties of substituted compounds. (orig.)

The effect of emulsifier on the stability of irradiated LA-TZ latex

International Nuclear Information System (INIS)

Made Sumarti K; Utama, Marga; Puspitasari, Tita

1998-01-01

The effect of six kinds of stabilizer on the stability of the concentrated LA-TZ latex which contains n-BA have been studied. The six stabilizers are: 1. Naphthalene sulfonic acid formaldehyde condensate, 2. Sodium dialkyl sulfosuccinate, 3. Triethanol amine lauryl sulfate, 4. Sodium polyoxyethylene alkyl phenol ether sulfate, 5. Dodecyl benzene sulfonic acid (Neopelex FS), and 6. Ammonium laurat. The concentrations of the stabilizers are in the range of 0,1 to 0,3% and of the n-BA is 5phr (per hundred rubber). The field natural rubber latex was stabilized by Tetramethyl tiuram disulfide - Zine oxide (TMTD-ZnO) and ammonium gas, and was concentrated by centrifuge. The obtain concentrated LA-TZ latex was added by the n-BA and was kept with various storage time i.e. o, 2, 4, 6, 18, and 24 hours. It was found that the stable latex was irradiated by 15 kGy dose and the physical properties was tested, then the maximum tensile strength of 223,3 kg/cm 2 was found on Neopelex FS concentrate at 0,1%. (authors)

Intermetallic Compound Growth and Stress Development in Al-Cu Diffusion Couple

Science.gov (United States)

Mishler, M.; Ouvarov-Bancalero, V.; Chae, Seung H.; Nguyen, Luu; Kim, Choong-Un

2018-01-01

This paper reports experimental observations evidencing that the intermetallic compound phase interfaced with Cu in the Al-Cu diffusion couple is most likely α2-Cu3Al phase, not γ-Cu9Al4 phase as previously assumed, and that its growth to a critical thickness may result in interface failure by stress-driven fracture. These conclusions are made based on an interdiffusion study of a diffusion couple made of a thick Cu plate coated with ˜ 2- μm-thick Al thin film. The interface microstructure and lattice parameter were characterized using scanning electron microscopy and x-ray diffraction analysis. Specimens aged at temperature between 623 K (350°C) and 723 K (450°C) for various hours produced consistent results supporting the main conclusions. It is found that disordered α2-Cu3Al phase grows in a similar manner to solid-state epitaxy, probably owing to its structural similarity to the Cu lattice. The increase in the interface strain that accompanies the α2-Cu3Al phase growth ultimately leads to interface fracture proceeding from crack initiation and growth along the interface. This mechanism provides the most consistent explanation for interface failures observed in other studies.

Subsolidus phase relations of the SrO-Ta2O5-CuO system at 900 °C in air

DEFF Research Database (Denmark)

Grivel, Jean-Claude

2009-01-01

The subsolidus phase relations of the SrO–Ta2O5–CuO system were investigated in air. The samples were equilibrated at 900 °C. The ternary oxide Sr3Ta2CuO9 compound is stable under these conditions. This phase presents a solid solution range, its actual composition being Sr3Ta2−xCu1+xO9+δ with 0.......0 ≤ x ≤ 0.2. Up to about 5 at.% Cu can be incorporated in the Sr3−xTa1+xO5.5+δ phase. Similarities with the SrO–Nb2O5–CuO system are discussed....

Construction of Hierarchical CuO/Cu2O@NiCo2S4 Nanowire Arrays on Copper Foam for High Performance Supercapacitor Electrodes

Science.gov (United States)

Zhou, Luoxiao; He, Ying; Jia, Congpu; Pavlinek, Vladimir; Saha, Petr; Cheng, Qilin

2017-01-01

Hierarchical copper oxide @ ternary nickel cobalt sulfide (CuO/Cu2O@NiCo2S4) core-shell nanowire arrays on Cu foam have been successfully constructed by a facile two-step strategy. Vertically aligned CuO/Cu2O nanowire arrays are firstly grown on Cu foam by one-step thermal oxidation of Cu foam, followed by electrodeposition of NiCo2S4 nanosheets on the surface of CuO/Cu2O nanowires to form the CuO/Cu2O@NiCo2S4 core-shell nanostructures. Structural and morphological characterizations indicate that the average thickness of the NiCo2S4 nanosheets is ~20 nm and the diameter of CuO/Cu2O core is ~50 nm. Electrochemical properties of the hierarchical composites as integrated binder-free electrodes for supercapacitor were evaluated by various electrochemical methods. The hierarchical composite electrodes could achieve ultrahigh specific capacitance of 3.186 F cm−2 at 10 mA cm−2, good rate capability (82.06% capacitance retention at the current density from 2 to 50 mA cm−2) and excellent cycling stability, with capacitance retention of 96.73% after 2000 cycles at 10 mA cm−2. These results demonstrate the significance of optimized design and fabrication of electrode materials with more sufficient electrolyte-electrode interface, robust structural integrity and fast ion/electron transfer. PMID:28914819

Construction of Hierarchical CuO/Cu2O@NiCo2S4 Nanowire Arrays on Copper Foam for High Performance Supercapacitor Electrodes

Directory of Open Access Journals (Sweden)

Luoxiao Zhou

2017-09-01

Full Text Available Hierarchical copper oxide @ ternary nickel cobalt sulfide (CuO/Cu2O@NiCo2S4 core-shell nanowire arrays on Cu foam have been successfully constructed by a facile two-step strategy. Vertically aligned CuO/Cu2O nanowire arrays are firstly grown on Cu foam by one-step thermal oxidation of Cu foam, followed by electrodeposition of NiCo2S4 nanosheets on the surface of CuO/Cu2O nanowires to form the CuO/Cu2O@NiCo2S4 core-shell nanostructures. Structural and morphological characterizations indicate that the average thickness of the NiCo2S4 nanosheets is ~20 nm and the diameter of CuO/Cu2O core is ~50 nm. Electrochemical properties of the hierarchical composites as integrated binder-free electrodes for supercapacitor were evaluated by various electrochemical methods. The hierarchical composite electrodes could achieve ultrahigh specific capacitance of 3.186 F cm−2 at 10 mA cm−2, good rate capability (82.06% capacitance retention at the current density from 2 to 50 mA cm−2 and excellent cycling stability, with capacitance retention of 96.73% after 2000 cycles at 10 mA cm−2. These results demonstrate the significance of optimized design and fabrication of electrode materials with more sufficient electrolyte-electrode interface, robust structural integrity and fast ion/electron transfer.

Cu2O-based solar cells using oxide semiconductors

International Nuclear Information System (INIS)

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 Cu 2 O heterojunction solar cells fabricated using p-type Cu 2 O 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 Cu 2 O sheets under various deposition conditions using a pulsed laser deposition method. In Cu 2 O-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-ZnGa 2 O 4 thin-film layer. In most of the Cu 2 O-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 Ga 2 O 3 -Al 2 O 3 systems, higher conversion efficiencies (η) as well as a high open circuit voltage (V oc ) were obtained by using a relatively small amount of MgO or Al 2 O 3 , e.g., (ZnO) 0.91 –(MgO) 0.09 and (Ga 2 O 3 ) 0.975 –(Al 2 O 3 ) 0.025 , respectively. When Cu 2 O-based heterojunction solar cells were fabricated using Al 2 O 3 –Ga 2 O 3 –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 V oc 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 Cu 2 O heterojunction solar cells fabricated using Na-doped Cu 2 O (Cu 2 O:Na) sheets that featured a resistivity controlled by optimizing the post-annealing temperature and duration. Consequently, an η of 6.25% and a V oc of 0.84 V were obtained in a MgF 2 /AZO/n-(Ga 2 O 3 –Al 2 O 3 )/p-Cu 2 O:Na heterojunction solar cell fabricated using

Cu2O-based solar cells using oxide semiconductors

Science.gov (United States)

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 (Ga0.975Al0.025)2

Thermal expansion of the heavy-fermion compound CeInCu2 at high pressure

International Nuclear Information System (INIS)

Kagayama, Tomoko; Oomi, Gendo; Onuki, Yoshichika; Komatsubara, Takemi

1994-01-01

The thermal expansion coefficient α of the heavy-fermion compound CeInCu 2 has been measured at high pressure up to 2 GPa in the temperature range from 6 to 300 K. It is found that the linear term in α(T) at low temperature decreases by the application of pressure. ((orig.))

One of two TolC-like proteins is involved in antibiotic resistance and biofilm formation of Actinobacillus pleuropneumoniae clinical isolate SC1516

Directory of Open Access Journals (Sweden)

Ying Li

2016-10-01

Full Text Available Actinobacillus pleuropneumoniae is the etiologic agent of porcine contagious pleuropneumonia, a significant disease that causes serious economic losses to the swine industry worldwide. Persistent infections caused by bacterial biofilms are recalcitrant to treat because of the particular drug resistance of biofilm-dwelling cells. TolC, a key component of multidrug efflux pumps, are responsible for multidrug resistance in many Gram-negative bacteria. In this study, we identified two TolC-like proteins, TolC1 and TolC2, in A. pleuropneumoniae. Deletion of tolC1, but not tolC2, caused a significant reduction in biofilm formation, as well as increased drug sensitivity of both planktonic and biofilm cells. The genetic-complementation of the tolC1 mutation restored the competent biofilm and drug resistance. Besides, biofilm formation was inhibited and drug sensitivity was increased by the addition of phenylalanine-arginine beta-naphthylamide (PAβN, a well-known efflux pump inhibitor (EPI, suggesting a role for EPI in antibacterial strategies towards drug tolerance of A. pleuropneumoniae. Taken together, TolC1 is required for biofilm formation and is a part of the multidrug resistance machinery of both planktonic and biofilm cells, which could supplement therapeutic strategies for resistant bacteria and biofilm-related infections of A. pleuropneumoniae clinical isolate SC1516.

Functional Implications of an Intermeshing Cogwheel-like Interaction between TolC and MacA in the Action of Macrolide-specific Efflux Pump MacAB-TolC*

Science.gov (United States)

Xu, Yongbin; Song, Saemee; Moeller, Arne; Kim, Nahee; Piao, Shunfu; Sim, Se-Hoon; Kang, Mooseok; Yu, Wookyung; Cho, Hyun-Soo; Chang, Iksoo; Lee, Kangseok; Ha, Nam-Chul

2011-01-01

Macrolide-specific efflux pump MacAB-TolC has been identified in diverse Gram-negative bacteria including Escherichia coli. The inner membrane transporter MacB requires the outer membrane factor TolC and the periplasmic adaptor protein MacA to form a functional tripartite complex. In this study, we used a chimeric protein containing the tip region of the TolC α-barrel to investigate the role of the TolC α-barrel tip region with regard to its interaction with MacA. The chimeric protein formed a stable complex with MacA, and the complex formation was abolished by substitution at the functionally essential residues located at the MacA α-helical tip region. Electron microscopic study delineated that this complex was made by tip-to-tip interaction between the tip regions of the α-barrels of TolC and MacA, which correlated well with the TolC and MacA complex calculated by molecular dynamics. Taken together, our results demonstrate that the MacA hexamer interacts with TolC in a tip-to-tip manner, and implies the manner by which MacA induces opening of the TolC channel. PMID:21325274

Functional implications of an intermeshing cogwheel-like interaction between TolC and MacA in the action of macrolide-specific efflux pump MacAB-TolC.

Science.gov (United States)

Xu, Yongbin; Song, Saemee; Moeller, Arne; Kim, Nahee; Piao, Shunfu; Sim, Se-Hoon; Kang, Mooseok; Yu, Wookyung; Cho, Hyun-Soo; Chang, Iksoo; Lee, Kangseok; Ha, Nam-Chul

2011-04-15

Macrolide-specific efflux pump MacAB-TolC has been identified in diverse gram-negative bacteria including Escherichia coli. The inner membrane transporter MacB requires the outer membrane factor TolC and the periplasmic adaptor protein MacA to form a functional tripartite complex. In this study, we used a chimeric protein containing the tip region of the TolC α-barrel to investigate the role of the TolC α-barrel tip region with regard to its interaction with MacA. The chimeric protein formed a stable complex with MacA, and the complex formation was abolished by substitution at the functionally essential residues located at the MacA α-helical tip region. Electron microscopic study delineated that this complex was made by tip-to-tip interaction between the tip regions of the α-barrels of TolC and MacA, which correlated well with the TolC and MacA complex calculated by molecular dynamics. Taken together, our results demonstrate that the MacA hexamer interacts with TolC in a tip-to-tip manner, and implies the manner by which MacA induces opening of the TolC channel.

New Mononuclear Cu(II Complexes and 1D Chains with 4-Amino-4H-1,2,4-triazole

Directory of Open Access Journals (Sweden)

Marinela M. Dîrtu

2013-12-01

Full Text Available The crystal structures of two mononuclear Cu(II NH2trz complexes [Cu(NH2trz4(H2O](AsF62 (I and [Cu(NH2trz4(H2O](PF62 (II as well as two coordination polymers [Cu(μ2-NH2trz2Cl]Cl∙H2O (III and [Cu(μ2-NH2trz2Cl] (SiF60.5∙1.5H2O (IV are presented. Cationic 1D chains with bridging bis-monodentate μ2-coordinated NH2trz and bridging μ2-coordinated chloride ligands are present in III and IV. In these coordination polymers, the Cu(II ions are strongly antiferromagnetically coupled with J = −128.4 cm−1 for III and J = −143 cm−1 for IV (H = −JΣSiSi+1, due to the nature of the bridges between spin centers. Inter-chain interactions present in the crystal structures were taken into consideration, as well as g factors, which were determined experimentally, for the quantitative modeling of their magnetic properties.

Evaluation of [64Cu]Cu-DOTA and [64Cu]Cu-CB-TE2A Chelates for Targeted Positron Emission Tomography with an αvβ6-Specific Peptide

Directory of Open Access Journals (Sweden)

Sven H. Hausner

2009-03-01

Full Text Available Significant upregulation of the integrin αvβ6 has been described as a prognostic indicator in several cancers, making it an attractive target for tumor imaging. This study compares variants of a PEGylated αvβ6-targeting peptide, bearing either an [>18F]fluorobenzoyl prosthetic group ([18F]FBA-PEG-A20FMDV2 or different [64Cu]copper chelators (DOTA-PEG-A20FMDV2, CB-TE2A-PEG-A20FMDV2. The compounds were evaluated in vitro by enzyme-linked immunosorbent assay (against the integrin αvβ6 and the closely related integrin αvβ6 and by cell labeling (αvβ6-positive DX3puroβ6/αvβ6-negative DX3puro and in vivo using micro-positron emission tomography in a mouse model bearing paired DX3puroβ6/Dx3puro xenografts. In vitro, all three compounds showed excellent αvβ6-specific binding (50% inhibitory concentration [IC50](αvβ6 = 3 to g nmol/L; IC50(αvβ3 > 10 (μmol/L. In vivo, they displayed comparable, preferential uptake for the αvβ6-expressmg xenograft over the αvβ6-negative control (> 4:1 ratio at 4 hours postinjection. Whereas [64Cu]Cu-DOTA-PEG-A20FMDV2 resulted in increased levels of radioactivity in the liver, [64Cu]Cu-CB-TE2A-PEG-A20FMDV2 did not. Significantly, both 64Cu-labeled tracers showed unexpectedly high and persistent levels of radioactivity in the kidneys (> 40% injected dose/g at 4 and 12 hours postinjection. The findings underscore the potential influence of the prosthetic group on targeted in vivo imaging of clinically relevant markers such as αvβ6. Despite identical targeting peptide moiety and largely equal in vitro behavior, both 64Cu-labeled tracers displayed inferior pharmacokinetics, making them in their present form less suitable candidates than the 18F-labeled tracer for in vivo imaging of αvβ6

Thermoelectric and mechanical properties of spark plasma sintered Cu{sub 3}SbSe{sub 3} and Cu{sub 3}SbSe{sub 4}: Promising thermoelectric materials

Energy Technology Data Exchange (ETDEWEB)

Tyagi, Kriti; Gahtori, Bhasker; Bathula, Sivaiah; Toutam, Vijaykumar; Sharma, Sakshi; Singh, Niraj Kumar; Dhar, Ajay, E-mail: adhar@nplindia.org [CSIR-Network of Institutes for Solar Energy, Materials Physics and Engineering, CSIR-National Physical Laboratory, Dr. K. S. Krishnan Road, New Delhi 110012 (India)

2014-12-29

We report the synthesis of thermoelectric compounds, Cu{sub 3}SbSe{sub 3} and Cu{sub 3}SbSe{sub 4}, employing the conventional fusion method followed by spark plasma sintering. Their thermoelectric properties indicated that despite its higher thermal conductivity, Cu{sub 3}SbSe{sub 4} exhibited a much larger value of thermoelectric figure-of-merit as compared to Cu{sub 3}SbSe{sub 3}, which is primarily due to its higher electrical conductivity. The thermoelectric compatibility factor of Cu{sub 3}SbSe{sub 4} was found to be ∼1.2 as compared to 0.2 V{sup −1} for Cu{sub 3}SbSe{sub 3} at 550 K. The results of the mechanical properties of these two compounds indicated that their microhardness and fracture toughness values were far superior to the other competing state-of-the-art thermoelectric materials.

Dispersive excitations in the high-temperature superconductor La2-xSrxCuO4

DEFF Research Database (Denmark)

Christensen, N.B.; McMorrow, D.F.; Rønnow, H.M.

2004-01-01

High-resolution neutron scattering experiments on optimally doped La(2-x)Sr(x)CuO(4) (x=0.16) reveal that the magnetic excitations are dispersive. The dispersion is the same as in YBa(2)Cu(3)O(6.85), and is quantitatively related to that observed with charge sensitive probes. The associated veloc...

Lattice parameter values and phase transitions for the Cu2Cd1-zMnzSnSe4 and Cu2Cd1-zFezSnSe4 alloys

International Nuclear Information System (INIS)

Moreno, E.; Quintero, M.; Morocoima, M.; Quintero, E.; Grima, P.; Tovar, R.; Bocaranda, P.; Delgado, G.E.; Contreras, J.E.; Mora, A.E.; Briceno, J.M.; Avila Godoy, R.; Fernandez, J.L.; Henao, J.A.; Macias, M.A.

2009-01-01

X-ray powder diffraction measurements and differential thermal analysis (DTA) were made on polycrystalline samples of the Cu 2 Cd 1-z Mn z SnSe 4 and Cu 2 Cd 1-z Fe z SnSe 4 alloy systems. The diffraction patterns were used to show the equilibrium conditions and to derive lattice parameter values. For Cu 2 Cd 0.8 Fe 0.2 SnSe 4 as well as for Cu 2 Cd 0.2 Fe 0.8 SnSe 4 the crystal structures were refined using the Rietveld method. It was found that the internal distortion parameter σ decreases as Cd is replaced by either Mn and/or Fe. For the Cu 2 Cd 1-z Mn z SnSe 4 and Cu 2 Cd 1-z Fe z SnSe 4 alloy systems, only two single solid phase fields, the tetragonal stannite α(I4-bar2m) and the wurtz-stannite δ (Pmn2 1 ) structures were found to occur in the diagram. In addition to the tetragonal stannite α phase extra X-ray diffraction lines due to MnSe and/or FeSe 2 were observed for as grown samples in the range 0.7 < z < 1.0. However, it was found that the amount of the extra phase decreased for the compressed samples.

Effect of MnCuFe{sub 2}O{sub 4} content on magnetic and dielectric properties of poly (O-Phenylenediamine)/MnCuFe{sub 2}O{sub 4} nanocomposites

Energy Technology Data Exchange (ETDEWEB)

Kannapiran, Nagarajan [PG and Research Department of Chemistry, Sri Ramakrishna Mission Vidyalaya College of Arts and Science, Coimbatore 641020, Tamil Nadu (India); Muthusamy, Athianna, E-mail: muthusrkv@gmail.com [PG and Research Department of Chemistry, Sri Ramakrishna Mission Vidyalaya College of Arts and Science, Coimbatore 641020, Tamil Nadu (India); Chitra, Palanisamy [PG and Research Department of Chemistry, Sri Ramakrishna Mission Vidyalaya College of Arts and Science, Coimbatore 641020, Tamil Nadu (India)

2016-03-01

Poly o-phenylenediamine (PoPD)/MnCuFe{sub 2}O{sub 4} nanocomposites with three different ratios of MnCuFe{sub 2}O{sub 4} (10%, 20%, 30% w/w) were synthesized by in-situ oxidative chemical polymerization method ammonium persulphate used as oxidant, while MnCuFe{sub 2}O{sub 4} nanoparticles was prepared by auto-combustion method. The structure, morphology and magnetic properties of synthesized PoPD/MnCuFe{sub 2}O{sub 4} nanocomposites were characterized by FT-IR, UV–visible absorption spectra, X-ray diffraction (XRD), Scanning electron microscopy (SEM), Transmission electron microscopy (TEM), Thermogravimetric analysis (TGA) and Vibrating sample magnetometer (VSM). FTIR spectra and XRD were confirmed the formation of the PoPD/MnCuFe{sub 2}O{sub 4} nanocomposites. The morphology of PoPD/MnCuFe{sub 2}O{sub 4} nanocomposites is visualized through SEM and TEM. The spherical morphology of the PoPD was confirmed using SEM analysis. Dielectric properties of PoPD/MnCuFe{sub 2}O{sub 4} nanocomposites at different temperatures have been performed in the frequency range of 50 Hz–5 MHz. The optical absorption experiments of PoPD/MnCuFe{sub 2}O{sub 4} nanocomposites reveal that the direct transition with an energy band gap is around 2 eV. - Highlights: • Green synthesis of PoPD (the polymerization carried out only in aqueous medium) by in-situ chemical polymerization method. • For the first time, PoPD incorporated with MnCuFe{sub 2}O{sub 4} with lesser particle size. • The auto combustion reaction, support to achieve less particle size. • Ferrite content affects the magnetic properties of the nanocomposites.

Structure family and polymorphous phase transition in the compounds with soft sublattice: Cu{sub 2}Se as an example

Energy Technology Data Exchange (ETDEWEB)

Qiu, Wujie [Department of Physics, East China Normal University, Shanghai 200241 (China); State Key Laboratory of High Performance Ceramics and Superfine Microstructure, Shanghai Institute of Ceramics, Chinese Academy of Sciences, Shanghai 200050 (China); Lu, Ping; Yuan, Xun; Liu, Huili; Shi, Xun; Chen, Lidong [State Key Laboratory of High Performance Ceramics and Superfine Microstructure, Shanghai Institute of Ceramics, Chinese Academy of Sciences, Shanghai 200050 (China); CAS Key Laboratory of Energy conversion Materials, Shanghai Institute of Ceramics, Chinese Academy of Sciences, Shanghai 200050 (China); Xu, Fangfang; Wu, Lihua [State Key Laboratory of High Performance Ceramics and Superfine Microstructure, Shanghai Institute of Ceramics, Chinese Academy of Sciences, Shanghai 200050 (China); Ke, Xuezhi, E-mail: wqzhang@mail.sic.ac.cn, E-mail: xzke@phy.ecnu.edu.cn, E-mail: jihuiy@uw.edu [Department of Physics, East China Normal University, Shanghai 200241 (China); Yang, Jiong [Materials Genome Institute, Shanghai University, Shanghai 200444 (China); Yang, Jihui, E-mail: wqzhang@mail.sic.ac.cn, E-mail: xzke@phy.ecnu.edu.cn, E-mail: jihuiy@uw.edu [Materials Science and Engineering Department, University of Washington, Seattle, Washington 98195 (United States); Zhang, Wenqing, E-mail: wqzhang@mail.sic.ac.cn, E-mail: xzke@phy.ecnu.edu.cn, E-mail: jihuiy@uw.edu [State Key Laboratory of High Performance Ceramics and Superfine Microstructure, Shanghai Institute of Ceramics, Chinese Academy of Sciences, Shanghai 200050 (China); Materials Genome Institute, Shanghai University, Shanghai 200444 (China)

2016-05-21

Quite a few interesting but controversial phenomena, such as simple chemical composition but complex structures, well-defined high-temperature cubic structure but intriguing phase transition, coexist in Cu{sub 2}Se, originating from the relatively rigid Se framework and “soft” Cu sublattice. However, the electrical transport properties are almost uninfluenced by such complex substructures, which make Cu{sub 2}Se a promising high-performance thermoelectric compound with extremely low thermal conductivity and good power factor. Our work reveals that the crystal structure of Cu{sub 2}Se at the temperature below the phase-transition point (∼400 K) should have a group of candidate structures that all contain a Se-dominated face-centered-cubic-like layered framework but nearly random site occupancy of atoms from the “soft” Cu sublattice. The energy differences among those structures are very low, implying the coexistence of various structures and thus an intrinsic structure complexity with a Se-based framework. Detailed analyses indicate that observed structures should be a random stacking of those representative structure units. The transition energy barriers between each two of those structures are estimated to be zero, leading to a polymorphous phase transition of Cu{sub 2}Se at increasing temperature. Those are all consistent with experimental observations.