Preparation, characterization and X-ray attenuation property of Gd2O3-based nanocomposites

Science.gov (United States)

Jayakumar, Sangeetha; Saravanan, T.; Philip, John

2017-11-01

In an attempt to develop an alternate to lead-based X-ray shielding material, we describe the X-ray attenuation property of nanocomposites containing Gd2O3 as nanofiller and silicone resin as matrix, prepared by a simple solution-casting technique. Gd2O3 nanoparticles of size 30 and 56 nm are used at concentrations of 25 and 2.5 wt%. The nanoparticles and the nanocomposites are characterized using X-ray diffraction (XRD) studies, small angle X-ray spectroscopy (SAXS), thermogravimetric analysis (TGA), differential scanning calorimetry (DSC) and atomic force microscopy (AFM). The X-ray attenuation property of nanocomposites, studied using an industrial X-ray unit, shows that nanocomposites containing nanoparticles of size 56 nm (G2) exhibit better attenuation than nanocomposites containing nanoparticles of size 30 nm (G1), which is attributed to the greater interfacial interaction between the G2 nanofillers and silicone matrix. In the case of nanocomposites containing G1 nanoparticles, the interfacial interaction between the nanofiller and the matrix is so weak that it results in pulling out of nanofillers, causing voids in the matrix, which act as X-ray transparent region, thereby reducing the overall X-ray attenuation property of G1 nanocomposites. This is further corroborated from the AFM images of the nanocomposites. The weight loss and heat flow curves of pure silicone matrix and the nanocomposites containing Gd2O3 nanoparticles of size 30 and 56 nm show the degradation of silicone resin, due to chain scission, between 403 and 622 °C. The same onset temperature (403 °C) of degradation of matrix with and without nanoparticles shows that the addition of nanofillers to the matrix does not deteriorate the thermal stability of the matrix. This confirms the thermal stability of nanocomposites. Therefore, our study shows that nanocomposites containing G2 nanoparticles are potential candidates for the development of X-ray opaque fabric material.

Elliptic Curve Integral Points on y2 = x3 + 3x ‑ 14

Science.gov (United States)

Zhao, Jianhong

2018-03-01

The positive integer points and integral points of elliptic curves are very important in the theory of number and arithmetic algebra, it has a wide range of applications in cryptography and other fields. There are some results of positive integer points of elliptic curve y 2 = x 3 + ax + b, a, b ∈ Z In 1987, D. Zagier submit the question of the integer points on y 2 = x 3 ‑ 27x + 62, it count a great deal to the study of the arithmetic properties of elliptic curves. In 2009, Zhu H L and Chen J H solved the problem of the integer points on y 2 = x 3 ‑ 27x + 62 by using algebraic number theory and P-adic analysis method. In 2010, By using the elementary method, Wu H M obtain all the integral points of elliptic curves y 2 = x 3 ‑ 27x ‑ 62. In 2015, Li Y Z and Cui B J solved the problem of the integer points on y 2 = x 3 ‑ 21x ‑ 90 By using the elementary method. In 2016, Guo J solved the problem of the integer points on y 2 = x 3 + 27x + 62 by using the elementary method. In 2017, Guo J proved that y 2 = x 3 ‑ 21x + 90 has no integer points by using the elementary method. Up to now, there is no relevant conclusions on the integral points of elliptic curves y 2 = x 3 + 3x ‑ 14, which is the subject of this paper. By using congruence and Legendre Symbol, it can be proved that elliptic curve y 2 = x 3 + 3x ‑ 14 has only one integer point: (x, y) = (2, 0).

Viscoplastic Matrix Materials for Embedded 3D Printing.

Science.gov (United States)

Grosskopf, Abigail K; Truby, Ryan L; Kim, Hyoungsoo; Perazzo, Antonio; Lewis, Jennifer A; Stone, Howard A

2018-03-16

Embedded three-dimensional (EMB3D) printing is an emerging technique that enables free-form fabrication of complex architectures. In this approach, a nozzle is translated omnidirectionally within a soft matrix that surrounds and supports the patterned material. To optimize print fidelity, we have investigated the effects of matrix viscoplasticity on the EMB3D printing process. Specifically, we determine how matrix composition, print path and speed, and nozzle diameter affect the yielded region within the matrix. By characterizing the velocity and strain fields and analyzing the dimensions of the yielded regions, we determine that scaling relationships based on the Oldroyd number, Od, exist between these dimensions and the rheological properties of the matrix materials and printing parameters. Finally, we use EMB3D printing to create complex architectures within an elastomeric silicone matrix. Our methods and findings will both facilitate future characterization of viscoplastic matrices and motivate the development of new materials for EMB3D printing.

Metallic glasses of the type Fe80B17X3

International Nuclear Information System (INIS)

Riedel, M.; Gnaser, H.; Ruedenauer, F.G.

1981-08-01

Absolute and relative practical sensitivities for Osub2sup+ - bombardement of 14 elements, present as a 3% admixture in a Fe80B17X3 metallic glass matrix, were determined by SIMS. The variation of sensitivity data between elements is similar to that found for pure element samples. The 3% admixture causes a small but statistically significant matrix effect on the matrix elements Fe and B. Comparison with yield data of the same minor impurity elements in other matrices (stainless steel, silicon) shows, that sensitivities in different matrices are within 30% for most elements, indicating the possibility of transferring relative sensitivity factor data determined on metallic glasses to other Fe-based alloys and thereby obtaining a semi- quantitative analysis. (author)

Pitting corrosion behaviour study of aluminium matrix composites (A3xx.x/SiCp); Estudio del comportamiento a la corrosion por picadura de materiales compuestos de matriz de aluminio (A3xx.x/SiCp)

Energy Technology Data Exchange (ETDEWEB)

Pardo, A.; Merino, M. C.; Merino, S.; Lopez, M. D.; Viejo, F.; Carboneras, M.; Arrabal, R.

2004-07-01

The influence of the SiCp proportion on the pitting corrosion of A3xx.x/SiC/xxp composites was studies by means of potenciodinamic polarization and double cyclic polarization in saline environment at 25 degree centigree A360/SiC/xxp matrix does not contain copper, whereas the A380/SiC/xxp matric contains 1,39-1,44 wt %Cu. The kinetic study was carried out by gravimetric measurements. The nature of corrosion products was analysed by low angle XRD and Scanning Electron Microscopy (SEM). The corrosion is due to nucleation and growth of Al{sub 2}O{sub 3}-3H{sub 2}O on the material surface. The corrosion increases with the reinforcement proportion, chloride concentration and copper content. (Author) 10 refs.

Investigating the local structure of B-site cations in (1-x)BaTiO3-xBiScO3 and (1-x)PbTiO3-xBiScO3 using X-ray absorption spectroscopy

Science.gov (United States)

Blanchard, Peter E. R.; Grosvenor, Andrew P.

2018-05-01

The structural properties of (1-x)BaTiO3-xBiScO3 and (1-x)PbTiO3-xBiScO3 were investigated using powder X-ray diffraction and X-ray absorption spectroscopy. Diffraction measurements confirmed that substituting small amounts of BiScO3 into BaTiO3 initially stabilizes a cubic phase at x = 0.2 before impurity phases begin to form at x = 0.5. BiScO3 substitution also resulted in noticeable changes in the local coordination environment of Ti4+. X-ray absorption near-edge spectroscopy (XANES) analysis showed that replacing Ti4+ with Sc3+ results in an increase in the off-centre displacement of Ti4+ cations. Surprisingly, BiScO3 substitution has no effect on the displacement of the Ti4+ cation in the (1-x)PbTiO3-xBiScO3 solid solution.

3-Loop massive O(T2F) contributions to the DIS operator matrix element Agg

International Nuclear Information System (INIS)

Ablinger, J.; Schneider, C.; Bluemlein, J.; Freitas, A. de; Hasselhuhn, A.; Round, M.; Manteuffel, A. von

2014-09-01

Contributions to heavy flavour transition matrix elements in the variable flavour number scheme are considered at 3-loop order. In particular a calculation of the diagrams with two equal masses that contribute to the massive operator matrix element A (3) gg,Q is performed. In the Mellin space result one finds finite nested binomial sums. In x-space these sums correspond to iterated integrals over an alphabet containing also square-root valued letters.

Precision Measurement of the Neutron Twist-3 Matrix Element dn2: Probing Color Forces

Energy Technology Data Exchange (ETDEWEB)

Posik, Matthew; Flay, David; Parno, Diana; Allada, Kalyan; Armstrong, Whitney; Averett, Todd; Benmokhtar, Fatiha; Bertozzi, William; Camsonne, Alexandre; Canan, Mustafa; Cates, Gordon; Chen, Chunhua; Chen, Jian-Ping; Choi, Seonho; Chudakov, Eugene; Cusanno, Francesco; Dalton, Mark; Deconinck, Wouter; De Jager, Cornelis; Deng, Xiaoyan; Deur, Alexandre; Dutta, Chiranjib; El Fassi, Lamiaa; Franklin, Gregg; Friend, Megan; Gao, Haiyan; Garibaldi, Franco; Gilad, Shalev; Gilman, Ronald; Glamazdin, Oleksandr; Golge, Serkan; Gomez, Javier; Guo, Lei; Hansen, Jens-Ole; Higinbotham, Douglas; Holmstrom, Timothy; Huang, J; Hyde, Charles; Ibrahim Abdalla, Hassan; Jiang, Xiaodong; Jin, Ge; Katich, Joseph; Kelleher, Aidan; Kolarkar, Ameya; Korsch, Wolfgang; Kumbartzki, Gerfried; LeRose, John; Lindgren, Richard; Liyanage, Nilanga; Long, Elena; Lukhanin, Oleksandr; Mamyan, Vahe; McNulty, Dustin; Meziani, Zein-Eddine; Michaels, Robert; Mihovilovic, Miha; Moffit, Bryan; Muangma, Navaphon; Nanda, Sirish; Narayan, Amrendra; Nelyubin, Vladimir; Norum, Blaine; Nuruzzaman, nfn; Oh, Yongseok; Peng, Jen-chieh; Qian, Xin; Qiang, Yi; Rakhman, Abdurahim; Riordan, Seamus; Saha, Arunava; Sawatzky, Bradley; Hashemi Shabestari, Mitra; Shahinyan, Albert; Sirca, Simon; Solvignon-Slifer, Patricia; Subedi, Ramesh; Sulkosky, Vincent; Tobias, William; Troth, Wolfgang; Wang, Diancheng; Wang, Y; Wojtsekhowski, Bogdan; Yan, X; Yao, Huan; Ye, Yunxiu; Ye, Zhihong; Yuan, Lulin; Zhan, X; Zhang, Y; Zhang, Y -W; Zhao, Bo; Zheng, Xiaochao

2014-07-01

Double-spin asymmetries and absolute cross sections were measured at large Bjorken x (0.25 lte x lte 0.90), in both the deep-inelastic and resonance regions, by scattering longitudinally polarized electrons at beam energies of 4.7 and 5.9 GeV from a transversely and longitudinally polarized 3He target. In this dedicated experiment, the spin structure function g2 on 3He was determined with precision at large x, and the neutron twist-three matrix element dn2 was measured at ?Q2? of 3.21 and 4.32 GeV2/c2, with an absolute precision of about 10?5. Our results are found to be in agreement with lattice QCD calculations and resolve the disagreement found with previous data at ?Q2?= 5 GeV2/c2. Combining dn2 and a newly extracted twist-four matrix element, fn2, the average neutron color electric and magnetic forces were extracted and found to be of opposite sign and about 60 MeV/fm in magnitude.

Fully constrained Majorana neutrino mass matrices using Σ(72 x 3)

Energy Technology Data Exchange (ETDEWEB)

Krishnan, R.; Harrison, P.F. [Warwick Univ., Coventry (United Kingdom); Scott, W.G. [Rutherford Appleton Laboratory, Chilton, Didcot (United Kingdom)

2018-01-15

In 2002, two neutrino mixing ansatze having trimaximally mixed middle (ν{sub 2}) columns, namely tri-chi-maximal mixing (TχM) and tri-phi-maximal mixing (TφM), were proposed. In 2012, it was shown that TχM with χ = ± (π)/(16) as well as TφM with φ = ± (π)/(16) leads to the solution, sin{sup 2} θ{sub 13} = (2)/(3) sin{sup 2} (π)/(16), consistent with the latest measurements of the reactor mixing angle, θ{sub 13}. To obtain TχM{sub (χ=±(π)/(16))} and TφM{sub (φ=±(π)/(16))}, the type I see-saw framework with fully constrained Majorana neutrino mass matrices was utilised. These mass matrices also resulted in the neutrino mass ratios, m{sub 1}: m{sub 2}: m{sub 3} = ((2+√2))/(1+√(2(2+√2))): 1: ((2+√2))/(-1+√(2(2+√2))). In this paper we construct a flavour model based on the discrete group Σ(72 x 3) and obtain the aforementioned results. A Majorana neutrino mass matrix (a symmetric 3 x 3 matrix with six complex degrees of freedom) is conveniently mapped into a flavon field transforming as the complex six-dimensional representation of Σ(72 x 3). Specific vacuum alignments of the flavons are used to arrive at the desired mass matrices. (orig.)

Genetic polymorphisms of matrix metalloproteinase 3 in primary sclerosing cholangitis

Science.gov (United States)

Juran, Brian D.; Atkinson, Elizabeth J.; Schlicht, Erik M.; Larson, Joseph J.; Ellinghaus, David; Franke, Andre; Lazaridis, Konstantinos N.

2011-01-01

Background The damaging cholestasis inherent to primary sclerosing cholangitis (PSC) results from bile duct stricturing because of progressive fibrosis. The matrix metalloproteinase 3 (MMP3) degrades a wide range of matrix components and is expressed by activated liver stellate cells, and so is a candidate for involvement with the fibrotic processes underlying PSC. Moreover, the MMP3 gene harbours polymorphisms associated with variation in its activity directly impacting clinical phenotypes. Aims We aimed to examine the influence of MMP3 polymorphisms on PSC risk and progression. Methods Nine single nucleotide polymorphisms (SNPs) tagging the common genetic variation of MMP3 were genotyped in 266 PSC patients and 407 controls. SNPs and inferred haplotypes were assessed for PSC association by logistic regression and score tests. The effect of SNPs on survival to liver transplant or death was analysed using Cox regression, and Kaplan–Meier curves were constructed. Results No association of PSC with individual SNPs or haplotypes of MMP3 was detected. However, progression to death or liver transplant was significantly associated with homozygosity for minor alleles of rs522616, rs650108 and rs683878, particularly among PSC patients with concurrent ulcerative colitis (UC) (strongest in redundant SNPs rs650108/rs683878, hazard ratio = 3.23, 95% confidence interval 1.45–7.25, P = 0.004). Conclusions Genetic variation in MMP3 influences PSC progression, possibly in the context of coexisting UC. While the functional variants and specific mechanisms remain unknown, this finding implicates the turnover of the extracellular matrix as an important and variable component of PSC pathogenesis. Efforts to understand this process could form the basis for developing effective treatments, which are currently lacking for PSC. PMID:21134112

The mineral chemistry and origin of inclusion matrix and meteorite matrix in the Allende CV3 chondrite

International Nuclear Information System (INIS)

Kornacki, A.S.; Wood, J.A.; Harvard Univ., Cambridge, MA

1984-01-01

The two textural varieties of olivine-rich Allende inclusions consist primarily of a porous, fine-grained mafic constituent that differs from the opaque meteorite matrix of CV3 chondrites by being relatively depleted in sulfides, metal grains, and carbonaceous material. Olivine is the most abundant mineral in Allende inclusion matrix; clinopyroxene, nepheline, sodalite, and Ti-Al-pyroxene occur in lesser amounts. Olivine in unrimmed olivine aggregates is ferrous and has a narrow compositional range. Olivine in rimmed olivine aggregates is, on average, more magnesian, with a wider compositional range. Olivine grains in the granular rims of Type 1B inclusions are zoned, with magnesian cores and ferrous rinds. Ferrous olivines in both varieties of inclusions commonly contain significant amounts of Al 2 O 3 , CaO and TiO 2 , refractory elements that probably occur in submicroscopic inclusions of Ca, Al, Ti-rich glass. Defocussed beam analyses of Allende matrix materials are discussed. (author)

Spontaneous metastasis in matrix metalloproteinase 3-deficient mice

DEFF Research Database (Denmark)

Juncker-Jensen, Anna; Rømer, John; Pennington, Caroline J

2009-01-01

Matrix metalloproteinases (MMPs) have been linked to the metastatic potential of tumor cells due to their ability to degrade the extracellular matrix. MMP-3 (stromelysin-1) is upregulated in a wide variety of human tumors. We used the MMTV-PyMT breast cancer model to determine if MMP-3 is involved...

Crystallographic Investigations into Properties of Acentric Hybrid Perovskite Single Crystals NH(CH3)3SnX3(X = Cl, Br)

KAUST Repository

Dang, Yangyang

2016-10-11

The hybrid perovskites with special optoelectronic properties have attracted more attention to the scientific and industrial applications. However, because of the toxicity and instability of lead complexes, there is interest in finding a nontoxic substitute for the lead in the halides perovskites and solving the ambiguous crystal structures and phase transition of NH(CH3)3SnX3 (X = Cl, Br). Here, we report the bulk crystal growths and different crystal morphologies of orthorhombic hybrid perovskites NH(CH3)3SnX3 (X = Cl, Br) in an ambient atmosphere by bottom-seeded solution growth (BSSG) method. More importantly, detailed structural determination and refinements, phase transition, band gap, band structure calculations, nonlinear optical (NLO) properties, XPS, thermal properties, and stability of NH(CH3)3SnX3 (X = Cl, Br) single crystals are demonstrated. NH(CH3)3SnCl3 single crystal undergoes reversible structural transformation from orthorhombic space group Cmc21 (no. 36) to monoclinic space group Cc (no. 9) and NH(CH3)3SnBr3 belongs to the orthorhombic space group Pna21 (no. 33) by DSC, single-crystal X-ray diffraction and temperature-dependent SHG measurements, which clarify the former results. These results should pave the way for further studies of these materials in optoelectronics.

Evaluation of flooded 3 x3x3 arrays of plutonium metal

International Nuclear Information System (INIS)

Pitts, M.; Rahnema, F.

1997-01-01

In the early 1980's, thirteen experiments using plutonium metal cylinders were performed at the Rocky Flats Critical Mass Laboratory. The experimental method consisted of flooding a 3 x3 x3 array with water until criticality was achieved. Ten of the thirteen experiments went critical while the other three remained subcritical upon full reflection. This paper evaluates these experiments to develop benchmark descriptions for validation of computational tools used by criticality safety specialists. Six of the ten critical experiments were found acceptable as benchmark experiments. Sensitivity studies were performed to find the effect of experimental limits and uncertainties on the k eff value. Analysis of the experiments was performed by MCNP with continuous energy ENDF/B-V cross section data. K eff values for all benchmark experiments were computed using MCNP with ENDF/B-V data, KENO-Va with Hansen Roach cross section, and KENO-Va with 27-group ENDF/B-IV cross sections. Although these experiments were flooded, KENO-Va calculations show that these were, in fact, fast systems. 3 refs., 1 fig., 7 tabs

Membrane-type-3 matrix metalloproteinase (MT3-MMP functions as a matrix composition-dependent effector of melanoma cell invasion.

Directory of Open Access Journals (Sweden)

Olga Tatti

Full Text Available In primary human melanoma, the membrane-type matrix metalloproteinase, MT3-MMP, is overexpressed in the most aggressive nodular-type tumors. Unlike MT1-MMP and MT2-MMP, which promote cell invasion through basement membranes and collagen type I-rich tissues, the function of MT3-MMP in tumor progression remains unclear. Here, we demonstrate that MT3-MMP inhibits MT1-MMP-driven melanoma cell invasion in three-dimensional collagen, while yielding an altered, yet MT1-MMP-dependent, form of expansive growth behavior that phenocopies the formation of nodular cell colonies. In melanoma cell lines originating from advanced primary or metastatic lesions, endogenous MT3-MMP expression was associated with limited collagen-invasive potential. In the cell lines with highest MT3-MMP expression relative to MT1-MMP, collagen-invasive activity was increased following stable MT3-MMP gene silencing. Consistently, MT3-MMP overexpression in cells derived from less advanced superficially spreading melanoma lesions, or in the MT3-MMP knockdown cells, reduced MT1-MMP-dependent collagen invasion. Rather than altering MT1-MMP transcription, MT3-MMP interacted with MT1-MMP in membrane complexes and reduced its cell surface expression. By contrast, as a potent fibrinolytic enzyme, MT3-MMP induced efficient invasion of the cells in fibrin, a provisional matrix component frequently found at tumor-host tissue interfaces and perivascular spaces of melanoma. Since MT3-MMP was significantly upregulated in biopsies of human melanoma metastases, these results identify MT3-MMP as a matrix-dependent modifier of the invasive tumor cell functions during melanoma progression.

The O(αs3) massive operator matrix elements of O(nf) for the structure function F2(x,Q2) and transversity

International Nuclear Information System (INIS)

Ablinger, J.; Bluemlein, J.; Klein, S.; Schneider, C.; Wissbrock, F.

2011-01-01

The contributions ∝n f to the O(α s 3 ) massive operator matrix elements describing the heavy flavor Wilson coefficients in the limit Q 2 >>m 2 are computed for the structure function F 2 (x,Q 2 ) and transversity for general values of the Mellin variable N. Here, for two matrix elements, A qq,Q PS (N) and A qg,Q (N), the complete result is obtained. A first independent computation of the contributions to the 3-loop anomalous dimensions γ qg (N), γ qq PS (N), and γ qq NS,(TR) (N) is given. In the computation advanced summation technologies for nested sums over products of hypergeometric terms with harmonic sums have been used. For intermediary results generalized harmonic sums occur, while the final results can be expressed by nested harmonic sums only.

Preparation and photoluminescence characteristics of In(OH){sub 3}:xTb{sup 3+} obtained by Microwave-Assisted Hydrothermal method

Energy Technology Data Exchange (ETDEWEB)

Motta, F.V., E-mail: fabiana@ct.ufrn.br [DEMAT, CT, UFRN, Av. Sen. Salgado Filho 3000, CEP 59072-970 Natal, RN (Brazil); Marques, A.P.A. [UNIFESP, Rua Prof. Artur Riedel 275, CEP 09972-270 Diadema, SP (Brazil); Li, M.S. [IFSC, USP, Av. Trabalhador São Carlense 400, CEP 13566-590 São Carlos, SP (Brazil); Abreu, M.F.C. [LIEC, DQ, UFSCar, Via Washington Luiz, km 235, CEP 13565-905 São Carlos, SP (Brazil); Paskocimas, C.A.; Bomio, M.R.D. [DEMAT, CT, UFRN, Av. Sen. Salgado Filho 3000, CEP 59072-970 Natal, RN (Brazil); Souza, R.P. [DEP, CT, UFRN, Av. Sen. Salgado Filho 3000, CEP 59072-970 Natal, RN (Brazil); Varela, J.A. [LIEC, IQ, UNESP, Rua Francisco Degni s/n, CEP 14801-907 Araraquara, SP (Brazil); Longo, E. [LIEC, DQ, UFSCar, Via Washington Luiz, km 235, CEP 13565-905 São Carlos, SP (Brazil)

2013-03-15

Highlights: ► We report the preparation by Microwave-Hydrothermal method of In(OH){sub 3}:xTb{sup 3+}. ► Nanostructures were obtained at a low temperature. ► The crystallite size decreased with terbium doping level. ► The nucleation–dissolution–recrystallization mechanism is promoted by processing. ► This material is a highly promising candidate for photoluminescent applications. -- Abstract: Crystalline terbium-doped indium hydroxide structures were prepared by a rapid and efficient Microwave-Assisted Hydrothermal (MAH) method. Nanostructures were obtained at a low temperature. FE-SEM images confirm that these samples are composed of 3D nanostructures. XRD, optical diffuse reflectance and photoluminescence (PL) measurements were used to characterize the products. Emission spectra of terbium-doped indium hydroxide (In(OH){sub 3}:xTb{sup 3+}) samples under excitation (350.7 nm) presented broad band emission referent to the indium hydroxide matrix and {sup 5}D{sub 4} → {sup 7}F{sub 6}, {sup 5}D{sub 4} → {sup 7}F{sub 5}, {sup 5}D{sub 4} → {sup 7}F{sub 4}, and {sup 5}D{sub 4} → {sup 7}F{sub 3} terbium transitions at 495, 550, 590 and 627 nm, respectively. Relative intensities of the Tb{sup 3+} emissions increased as the concentration of this ion increased from 0, 1, 2, 4 and 8 mol%, of Tb{sup 3+}, but the luminescence is drastically quenched for the In(OH){sub 3} matrix.

Photoluminescence Properties of Red-Emitting Ca3Sr3-x(PO4)4:xEu3+ Phosphors for White Light-Emitting Diodes.

Science.gov (United States)

Hakeem, D A; Park, K

2015-07-01

The photoluminescent properties of the Eu(3+)-activated Ca3Sr3(PO4)4 phosphors prepared by a solution combustion method were investigated. The excitation spectra of Ca3Sr3-x(PO4)4:xEu3+ (0.05 ≤ x ≤ 0.6) phosphors under 614 nm wavelength showed a broad band centered at 266 nm along with other peaks at 320, 362, 381, 394, 414, 464, and 534 nm. The emission spectra observed in the range of 450 to 750 nm under excitation at 394 nm were ascribed to the 5D0-7F1-4 transitions of Eu3+ ions. The Ca3Sr3-x(PO4)4:xEu3+ phosphors showed the strongest red emission at 614 nm due to the electric dipole 5DO -->7F2 transition of Eu3+. The strongest emission intensity was obtained for the Eu3+ ions of x = 0.5. The prepared Ca3Sr3-x(PO4)4:xEu3+ can be used as an efficient red phosphor for UV-based white LEDs.

Structure refinement, far infrared spectroscopy, and dielectric characterization of (1-x)La(Mg1/2Ti1/2)O3-xLa2/3TiO3 solid solutions

Science.gov (United States)

Salak, Andrei N.; Khalyavin, Dmitry D.; Ferreira, Victor M.; Ribeiro, José L.; Vieira, Luís G.

2006-05-01

Dielectric properties of (1-x)La(Mg1/2Ti1/2)O3-xLa2/3TiO3 [(1-x)LMT-xLT] ceramics (0infrared (FIR) frequency ranges. The crystal structure sequence in (1-x)LMT-xLT reported by different authors has been analyzed and revised. FIR spectroscopy was used to characterize the lattice contribution to the dielectric response at microwave frequencies. The complex dielectric function was evaluated from the reflectivity data and extrapolated down to a gigahertz range. Compositional variations of the fundamental microwave dielectric parameters estimated by different methods are compared and discussed. The dependence of the quality factor on the composition in LMT-LT is interpreted in terms of the reduction of spatial phonon correlations originated from the increasing amount of La vacancies. This approach could account for the compositional behavior of the dielectric loss commonly observed in a number of microwave mixed systems.

AdS3 xw (S3 x S3 x S1) solutions of type IIB string theory

International Nuclear Information System (INIS)

Donos, Aristomenis; Gauntlett, Jerome P.; Imperial College, London; Sparks, James

2008-10-01

We analyse a recently constructed class of local solutions of type IIB supergravity that consist of a warped product of AdS 3 with a sevendimensional internal space. In one duality frame the only other nonvanishing fields are the NS three-form and the dilaton. We analyse in detail how these local solutions can be extended to globally well-defined solutions of type IIB string theory, with the internal space having topology S 3 x S 3 x S 1 and with properly quantised three-form flux. We show that many of the dual (0,2) SCFTs are exactly marginal deformations of the (0,2) SCFTs whose holographic duals are warped products of AdS 3 with seven-dimensional manifolds of topology S 3 x S 2 x T 2 . (orig.)

Study of the spectroscopy properties of uranium matrix doped with europium. Energy transfer between UO22+ and Eu3+

International Nuclear Information System (INIS)

Luiz, Jose Eduardo Monteiro de Sa

2007-01-01

Uranyl compounds (UO 2 2+ ) present a great potential as luminescent materials, for instance, applied in technology laser, luminescent probes, cells for conversion of energy, etc. In this work it is studied the efficiency of energy transfer in the compound Eu 3+ doped in UO 2 (MS) 2 .(H 2 O)n matrix and UO 2 2+ in Eu(MS) 3 (H 2 O)n for to be used as efficient Light Conversion Molecular Devices (LCMD) and/or in solar cells for energy conversion. It is also described the synthesis, characterization and spectroscopic study of the matrix Eu(MS) 3 .(H 2 O)n.(x%mol) UO 2 2+ and UO 2 (MS) 2 .(H 2 O)n.(x%mol) Eu 3+ (where x= 1, 3, 5 and 10). The compounds obtained was characterized by elementary analyses for determine the U 6+ concentration, infrared spectra, thermal analyses and luminescence spectra. The IR data suggest that the MS ligand acts as bidentate one. The emission spectra of Eu 3+ doped in UO 2 (MS) 2 .(H 2 O) 2 matrix showed characteristic fluorescence bands of the uranyl ion, attributed to the transition of 3 Π u -> 1 Σ g + of the uranium matrix. For the UO 2 2+ in Eu(MS) 3 (H 2 O) 6 the transitions of D o -> 7 F J (J=0 ->4 ) are predominant in the spectra. The intense europium luminescence associated with uranyl sensitising is registered in emission spectra of Eu 3+ ions in the range of 420-720 nm. The quenching rate constant of UO 2 2+ fluorescence with Eu 3+ is also determined. (author)

Lead-Free KNbO3:xZnO Composite Ceramics.

Science.gov (United States)

Lv, Xiang; Li, Zhuoyun; Wu, Jiagang; Xiao, Dingquan; Zhu, Jianguo

2016-11-09

It is a tough issue to develop dense and water resistant KNbO 3 ceramics due to high evaporation and hygroscopicity of K 2 O. Here, KNbO 3 :xZnO composite ceramics were used to successfully solve this problem, where ZnO particles were randomly distributed into a KNbO 3 matrix. The addition of ZnO hardly affects the phase structure of KNbO 3 , and moreover, the enhancement of electrical properties, thermal stability, and aging characteristics was observed in KNbO 3 :xZnO composite ceramics. The composites possessed the maximum d 33 of 120 ± 5 pC/N, which is superior to that of pure KNbO 3 (d 33 = 80 pC/N). More importantly, a strong water resistance and an aging-free characteristic were observed in KNbO 3 :0.4ZnO. This is the first time for KNbO 3 ceramics to simultaneously improve electrical properties and resolve the water-absorbing properties. We believe that these composite ceramics are promising for practical applications.

Giant Faraday rotation in Bi(x)Ce(3-x)Fe5O12 epitaxial garnet films.

Science.gov (United States)

Chandra Sekhar, M; Singh, Mahi R; Basu, Shantanu; Pinnepalli, Sai

2012-04-23

Thin films of Bi(x)Ce(3-x)Fe(5)O(12) with x = 0.7 and 0.8 compositions were prepared by using pulsed laser deposition. We investigated the effects of processing parameters used to fabricate these films by measuring various physical properties such as X-ray diffraction, transmittance, magnetization and Faraday rotation. In this study, we propose a phase diagram which provides a suitable window for the deposition of Bi(x)Ce(3-x)Fe(5)O(12) epitaxial films. We have also observed a giant Faraday rotation of 1-1.10 degree/µm in our optimized films. The measured Faraday rotation value is 1.6 and 50 times larger than that of CeYIG and YIG respectively. A theoretical model has been proposed for Faraday rotation based on density matrix method and an excellent agreement between experiment and theory is found. © 2012 Optical Society of America

Crystal structure and lithium ion conductivity of A-site deficient perovskites La1/3-xLi3xTaO3

International Nuclear Information System (INIS)

Mizumoto, Katsuyoshi; Hayashi, Shinsuke

1997-01-01

The crystal structure and lithium ion conductivity of La 1/3-x Li 3x TaO 3 solid solutions with the A-site deficient perovskite structure have been studied. Single phase solid solutions were obtained in the range of x=0 to 1/6. Change from tetragonal to cubic structure and decrease in the lattice volume were observed with increasing the x value. The maximum conductivity obtained was 7 x 10 -3 S·m -1 at x=0.06. The composition-dependence on the carrier concentration was calculated and compared with conductivity data. (author)

Electric-Field Control of Magnetism in Co40Fe40B20/(1-x)Pb(Mg1/3Nb2/3)O3-xPbTiO3 Multiferroic Heterostructures with Different Ferroelectric Phases.

Science.gov (United States)

Liu, Yan; Zhao, Yonggang; Li, Peisen; Zhang, Sen; Li, Dalai; Wu, Hao; Chen, Aitian; Xu, Yang; Han, X F; Li, Shiyan; Lin, Di; Luo, Haosu

2016-02-17

Electric-field control of magnetism in multiferroic heterostructures composed of Co40Fe40B20 (CoFeB) and (1-x)Pb(Mg1/3Nb2/3)O3-xPbTiO3 (PMN-xPT) with different ferroelectric phases via changing composition and temperature is explored. It is demonstrated that the nonvolatile looplike bipolar-electric-field-controlled magnetization, previously found in the CoFeB/PMN-xPT heterostructures with PMN-xPT in the rhombohedral (R) phase around the morphotropic phase boundary (MPB), also occurs for PMN-xPTs with both R phase (far away from MPB) and monoclinic (M) phase, suggesting that the phenomenon is the common feature of CoFeB/PMN-xPT multiferroic heterostructures for PMN-xPT with different phases. The magnitude of the effect changes with increasing temperature and volatile bipolar-electric-field-controlled magnetization with a butterflylike behavior occurs when the ferroelectric phase changes to the tetragonal phase (T). Moreover, for the R-phase sample with x = 0.18, an abrupt and giant increase of magnetization is observed at a characteristic temperature in the temperature dependence of magnetization curve. These results are discussed in terms of coupling between magnetism and ferroelectric domains including macro- and microdomains for different ferroelectric phases. This work is helpful for understanding the phenomena of electric-field control of magnetism in FM/FE multiferroic heterostructures and is also important for applications.

Development of an elevated temperature aluminum alloy containing Al3X-type dispersed phases

International Nuclear Information System (INIS)

Zedalis, M.S.

1985-01-01

The extents of solid solubility in the equilibrium, tetragonal Al 3 X-type dispersed phases (X represents binary and ternary combinations of Hf, Ti, V, and Zr) were examined using powder x-ray diffraction methods. Minimum lattice disregistry (delta) with the Al(ss) matrix was achieved by maximizing the amount of Ti or V added to the Al 3 Hf and/or Al 3 Zr phases without forming a co-intermetallic compound exhibiting a DO 22 crystal structure. In comparison to Al 3 Zr, with a (delta) equal to 2.88%, the addition of V to Al 3 Zr in the ratio 7:1, i.e., Al 3 (v/sub 0.875/Zr/sub 0.125/), results in a decrease in (delta) by approximately 17%. Electron diffraction revealed that the addition of V to the metastable cubic (L1 2 ) Al 3 Zr phase also resulted in a reduction in the lattice disregistry across the precipitate/matrix boundary. In comparison with the cubic Al 3 Zr phase, with a (delta) of approximately 1.0%, the Al 3 (V/sub 0.875/Zr/sub 0.125/) phase exhibits a mismatch of approximately -0.14%. The cubic Al 3 (V/sub 0.875/Zr/sub 0.125/) phase was observed by TEM to be substantially more stable, i.e., resist transformation to the equilibrium tetragonal phase, when compared to the cubic Al 3 Zr phase. It is proposed that a reduction in lattice disregistry results in a decrease in the strain energy component of the system's total free energy. A systematic decrease in the coarsening rate with a reduction in the lattice disregistry for the cubic Al 3 Zr, Al 3 (V/sub 0.725/Zr/sub 0.275/) and Al 3 (V/sub 0.875/Zr/sub 0.125/) and tetragonal Al 3 Zr and Al 3 (V/sub 0.875/Zr/sub 0.125/) phases is proposed to be representative of a decrease in the interfacial energy across the precipitate/matrix boundary

Impedance and magnetoelectric characteristics of (1 - x)BaTiO3- xLa0.7Sr0.3MnO3 ( x = 0.1 and 0.3) nano-composites

Science.gov (United States)

Nayek, C.; Murugavel, P.; Dinesh Kumar, S.; Subramanian, V.

2015-08-01

We have synthesized the phase-pure (1 - x)BaTiO3- xLa0.7Sr0.3MnO3 ( x = 0.1 and 0.3) magnetoelectric composites without interdiffusion among the existing phases. The magnetic measurements revealed an anomaly at the ferroelectric Curie temperature (393 K) of BaTiO3, and the dielectric data revealed an anomaly at the ferromagnetic transition temperature (360 K) of La0.7Sr0.3MnO3 ascertaining the magnetoelectric coupling in the composite. Impedance analysis indicated dipolar polarization contributions to the dielectric spectrum with two non-Debye-type relaxations. Both the grain and grain boundary contributions were present in the system with dominant grain boundary effect in all the composites. The composites show semiconducting behavior with the barrier hopping-type conducting mechanism. To avoid the free charge carrier and the space charge contributions, the magnetoelectric response was measured at high frequency range. The maximum values of magnetoelectric voltage coefficient measured at 100 kHz were 221 and 219 mV/Oe-cm for x = 0.1 and 0.3 samples, respectively.

Synthesis of Y{sub 1-x}Al{sub x}Ba{sub 2}Cu{sub 3}O{sub 7-δ} via combustion route: Effects of Al{sub 2}O{sub 3} nanoparticles on superconducting properties

Energy Technology Data Exchange (ETDEWEB)

Mohd Suan, Mohd Shahadan, E-mail: mohdshahadan@utem.edu.my [Department of Engineering Materials, Faculty of Manufacturing Engineering, Universiti Teknikal Malaysia Melaka, 76100 Durian Tunggal, Melaka (Malaysia); Johan, Mohd Rafie [Nanomaterial Engineering Research Group, Advanced Materials Research Laboratory, Department of Mechanical Engineering, University of Malaya, 50603 Kuala Lumpur (Malaysia)

2017-02-01

Combustion reaction was used to synthesis Al{sub 2}O{sub 3} nanoparticles embedded Y{sub 1-x}Al{sub x}Ba{sub 2}Cu{sub 3}O{sub 7-δ} simultaneously. The effects of Al{sub 2}O{sub 3} nanoparticles with nominal molar mass (x{sub mol}) of 0.02, 0.04, 0.06, 0.08 and 0.10 towards the critical current density J{sub C} of Y{sub 1-x}Al{sub x}Ba{sub 2}Cu{sub 3}O{sub 7-δ} were verified by magnetic measurement. Resulted XRD patterns revealed that the calcined samples consist of pure Al{sub 2}O{sub 3} and Y{sub 1-x}Al{sub x}Ba{sub 2}Cu{sub 3}O{sub 7-δ} phases which had been confirmed by EDX results. The SEM images showed that Al{sub 2}O{sub 3} nanoparticles (~10 nm) were distributed in polycrystalline YBa{sub 2}Cu{sub 3}O{sub 7-δ} grains and grain boundaries. The presence of higher concentration of Al{sub 2}O{sub 3} nanoparticles has developed Al{sup 3+} rich spots which diffused within the YBa{sub 2}Cu{sub 3}O{sub 7-δ} superconducting matrix to form Y{sub 1-x}Al{sub x}Ba{sub 2}Cu{sub 3}O{sub 7-δ} and was confirmed by EDX analysis. The samples were electrically superconducting at temperature above 85 K as measured by using standard four-probe technique. The magnetic field (H) dependent magnetization (M), M-H hysteresis loops measured at 77 K for x{sub mol}≤0.06 samples are significantly improved attributed to the increase of trapped fluxes in the samples. Remarkable increase of magnetic J{sub C} (H) in Al{sub 2}O{sub 3} nanoparticles added samples compared to the as prepared polycrystalline YBa{sub 2}Cu{sub 3}O{sub 7-δ} sample indicating strong pinning effect. It is suggested that well-distributed Al{sub 2}O{sub 3} nanoparticles in the polycrystalline YBa{sub 2}Cu{sub 3}O{sub 7-δ} matrix achieved via auto-combustion reaction has efficiently pin the magnetic vortex. The magnetic J{sub C} was optimized to ~6 kAcm{sup -2} in x{sub mol}=0.06 sample. On the other hand, insignificant magnetic J{sub C} improvement in x{sub mol}≥0.08 samples is probably resulted from the

Extrinsic and intrinsic magnetic properties of Co1-x Fex Sb3

International Nuclear Information System (INIS)

Amornpitoksuk, P.; Ravot, D.; Mauger, A.; Tedenac, J.C.

2007-01-01

We report magnetic properties of iron in Co 1-x Fe x Sb 3 for x in the range 0 3+ in the low spin d 5 configuration in presence of a strong crystal field that screens the orbital momentum. The magnetic properties give evidence that a small fraction of iron is spin-frozen in magnetite ferrimagnetic clusters, and antiferromagnetic FeO clusters. Because both types of clusters represent only very minor phases, their detection by the usual analytical means such as X-rays is not possible. The remaining part is diluted in the matrix to form a semimagnetic semiconductor characterized by a Fe-Fe nearest-neighbor exchange interaction J that is antiferromagnetic, with |J|/k B ∼19.6 degree K

EPR of some low-spin dsup(5) tris-chelate complexes of Fe(3), Ru(3), Os(3) in liquid-crystal matrix

International Nuclear Information System (INIS)

Domracheva, N.E.; Konstantinov, V.N.; Luchkona, S.A.; Ovchinnikov, I.V.

1985-01-01

Using the EPR method low-spin trischelate complexes of Fe, Ru, Os with 8-mercaptoquinoline and 8-oxyquinoline in oriented vitrified liquid-crystal matrix have been studied. Analtysis of angular dependences of EPR spectra of the complexes permitted to correlate the main axes of g-tensor with molecular axes and, consequently, to determine unambiguously the main electron states of the systems, as well as the value of crystal splittings. It is shown that in the complexes studied the splitting of energy levels is mainly determined by spin-orbital interaction, and not by axial or rhombic components of crystal field. However, rhombic distortion is responsible for anisotropy of g-tensor in xy plane and anisotropy of x- and y-axes orientation. The way to orient complexes in liquid-crystal matrix is substantiated; symmetry axis of the third order C 3 (Z) is mainly oriented along the director. Parameters of the function of orientational distribution of the complex axes are obtained

Electrical transport in low-lead (1-x)BaTiO3–xPbMg1/3Nb2/3O3 ceramics

Institute of Scientific and Technical Information of China (English)

J. SUCHANICZ; K. KONIECZNY; K. ŚWIERCZEK; M. LIPIŃSKI; M. KARPIERZ; D. SITKO; H. CZTERNASTEK; K. KLUCZEWSKA

2017-01-01

Low-lead (1-x)BaTiO3–xPbMg1/3Nb2/3O3 ceramics (x = 0, 0.025, 0.05, 0.075, 0.1, and 0.15) were prepared by the conventional oxide mixed sintering process, and their optical band gap, Seebeck coefficient, ac ( σac ) and dc ( σdc ) conductivities as a function of temperature were investigated for the first time. It was found that all samples have p-type conductivity. The low-frequency (20 Hz–2 MHz) ac conductivity obeys a power law σac ~ ωs , which is characteristic for disordered materials. The frequency exponent s is a decreasing function of temperature and tends to zero at high temperature. σac is proportional to ω0.07 – ω0.31 in the low-frequency region and to ω0.51 – ω0.98 in the high-temperature region. The temperature dependence of the dc conductivity showed a change in slope around the temperature at which the phase transition appeared. Both ac and dc conductivities showed a thermally activated character and possessed linear parts with different activation energies and some irregular changes. It was found that the hopping charge carriers dominate at low temperature and small polarons and oxygen vacancies dominate at higher temperature. (1-x)BaTiO3–xPbMg1/3Nb2/3O3 ceramics are expected to be promising new candidate for low-lead electronic materials.

Matrix dimensions bias demographic inferences: implications for comparative plant demography.

Science.gov (United States)

Salguero-Gómez, Roberto; Plotkin, Joshua B

2010-12-01

While the wealth of projection matrices in plant demography permits comparative studies, variation in matrix dimensions complicates interspecific comparisons. Collapsing matrices to a common dimension may facilitate such comparisons but may also bias the inferred demographic parameters. Here we examine how matrix dimension affects inferred demographic elasticities and how different collapsing criteria perform. We analyzed 13 x 13 matrices representing nine plant species, collapsing these matrices (i) into even 7 x 7, 5 x 5, 4 x 4, and 3 x 3 matrices and (ii) into 5 x 5 matrices using different criteria. Stasis and fecundity elasticities increased when matrix dimension was reduced, whereas those of progression and retrogression decreased. We suggest a collapsing criterion that minimizes dissimilarities between the original- and collapsed-matrix elasticities and apply it to 66 plant species to study how life span and growth form influence the relationship between matrix dimension and elasticities. Our analysis demonstrates that (i) projection matrix dimension has significant effects on inferred demographic parameters, (ii) there are better-performing methods than previously suggested for standardizing matrix dimension, and (iii) herbaceous perennial projection matrices are particularly sensitive to changes in matrix dimensionality. For comparative demographic studies, we recommend normalizing matrices to a common dimension by collapsing higher classes and leaving the first few classes unaltered.

Reactive synthesis of NbAl3 matrix composites

International Nuclear Information System (INIS)

Lu, L.; Kim, Y.S.; Gokhale, A.B.; Abbaschian, R.

1990-01-01

NbAl 3 matrix composites were synthesized in-situ via reactive hot compaction (RHC) of elemental powders. It was found that the simultaneous application of pressure during synthesis was effective in attaining a near-theoretical density matrix at relatively low temperatures and pressures. Using this technique, two types of composites were produced: matrices containing a uniform dispersion of second phase particles (either Nb 3 Al or Nb 2 Al with an Nb core or Nb 2 Al) and matrices reinforced with coated or uncoated ductile Nb filaments. It was found that a limited amount of toughening is obtained using the first approach, while composites containing coated Nb filaments exhibited a significant increase in the ambient temperature fracture toughness. In this paper, various aspects of RHC processing of NbAl 3 matrix composites, the effect of initial stoichiometry and powder size on the microstructure, as well as the mechanical behavior of the composites are discussed

White emitting phosphors based on glasses of the type 10AlF3–10TiO2–39PbO–30H3BO3–10SiO2–xEu2O3–(1−x)Tb2O3: An energy transfer study

International Nuclear Information System (INIS)

Wileńska, D.; Szczodrowski, K.; Mahlik, S.; Kukliński, B.; Grinberg, M.; Kłonkowski, A.M.

2015-01-01

Glasses consisting of heavy metal oxides, a metal fluoride and two lanthanoid oxides (as dopants) of the type 10AlF 3 –10TiO 2 –39PbO–30H 3 BO 3 –10SiO 2 –xEu 2 O 3 –(1−x)Tb 2 O 3 were prepared as phosphors with different molar ratio x. The un-doped matrix glass was characterized by XRD and DSC techniques. Its structure was also studied by FTIR techniques that suggested the presence of B–O − , B–Ø–B, Pb–O, Al–Ø–B and Al–O − bonds as well as [BO 3 ] 3− , [BØO 3 ], [BØ 4 ], and [SiØ 4 ] structural units as well as Ln–O–Ln clusters. For the Eu 3+ and Tb 3+ co-doped luminescent glasses optical absorption, luminescence and excitation spectra were recorded as well as time resolved luminescence techniques was used. Two luminescence effects were analyzed, viz. cross-relaxation Tb 3+ →Tb 3+ energy transfer and Tb 3+ →Eu 3+ energy transfer. The CIE diagram suggests that especially the glass co-doped with Eu 3+ and Tb 3+ in molar ratio x=0.5 can be recognized as a cold white phosphor. - Highlights: • Oxyfluoride glasses co-doped with Eu3+ and Tb3+ ions were prepared. • For the luminescent glasses among others optical absorption, luminescence and time resolved results were analyzed. • Cross-relaxation Tb3+ → Tb3+ energy transfer and Tb3+ → Eu3+ energy transfer were observed. • The glass co-doped with Eu3+ and Tb3+ ions can be recognized as a white phosphor

Discovery of novel solid solution Ca3Si3-x O3+x N4-2x : Eu2+ phosphors: structural evolution and photoluminescence tuning.

Science.gov (United States)

Wang, Baochen; Liu, Yan-Gai; Huang, Zhaohui; Fang, Minghao; Wu, Xiaowen

2017-12-22

Discovery of novel phosphors is one of the main issues for improving the color rendering index (CRI) and correlated color temperature (CCT) of white light-emitting diodes (w-LEDs). This study mainly presents a systematic research on the synthesis, crystal structure variation and photoluminescence tuning of novel (oxy)nitride solid solution Ca 3 Si 3-x O 3+x N 4-2x : Eu 2+ phosphors. XRD refinements show that lattice distortion occurs when x value diverges the optimum one (x = 1). The lattice distortion causes a widening of emission spectrum and an increase of Stokes shift (ΔSS), which leads to a bigger thermal quenching. With decrease of x value, the emission spectrum shows an obvious red-shift from 505.2 to 540.8 nm, which is attributed to the crystal field splitting. The enhanced crystal field splitting also broadens the excitation spectrum, making it possible to serve as the phosphor for near ultraviolet (n-UV) LEDs. A 3-phosphor-conversion w-LED lamp was fabricated with the as-prepared phosphor, which exhibits high CRI (Ra = 85.29) and suitable CCT (4903.35 K). All these results indicate that the Ca 3 Si 3-x O 3+x N 4-2x : Eu 2+ phosphor can serve as the green phosphor for n-UV w-LEDs, with a tunable spectrum by controlling the crystal structure and morphology.

Collagenous matrix supported by a 3D-printed scaffold for osteogenic differentiation of dental pulp cells.

Science.gov (United States)

Fahimipour, Farahnaz; Dashtimoghadam, Erfan; Rasoulianboroujeni, Morteza; Yazdimamaghani, Mostafa; Khoshroo, Kimia; Tahriri, Mohammadreza; Yadegari, Amir; Gonzalez, Jose A; Vashaee, Daryoosh; Lobner, Douglas C; Jafarzadeh Kashi, Tahereh S; Tayebi, Lobat

2018-02-01

A systematic characterization of hybrid scaffolds, fabricated based on combinatorial additive manufacturing technique and freeze-drying method, is presented as a new platform for osteoblastic differentiation of dental pulp cells (DPCs). The scaffolds were consisted of a collagenous matrix embedded in a 3D-printed beta-tricalcium phosphate (β-TCP) as the mineral phase. The developed construct design was intended to achieve mechanical robustness owing to 3D-printed β-TCP scaffold, and biologically active 3D cell culture matrix pertaining to the Collagen extracellular matrix. The β-TCP precursor formulations were investigated for their flow-ability at various temperatures, which optimized for fabrication of 3D printed scaffolds with interconnected porosity. The hybrid constructs were characterized by 3D laser scanning microscopy, X-ray diffraction, Fourier transform infrared spectroscopy, and compressive strength testing. The in vitro characterization of scaffolds revealed that the hybrid β-TCP/Collagen constructs offer superior DPCs proliferation and alkaline phosphatase (ALP) activity compared to the 3D-printed β-TCP scaffold over three weeks. Moreover, it was found that the incorporation of TCP into the Collagen matrix improves the ALP activity. The presented results converge to suggest the developed 3D-printed β-TCP/Collagen hybrid constructs as a new platform for osteoblastic differentiation of DPCs for craniomaxillofacial bone regeneration. Copyright © 2017. Published by Elsevier Ltd.

Crystallographic Investigations into Properties of Acentric Hybrid Perovskite Single Crystals NH(CH3)3SnX3(X = Cl, Br)

KAUST Repository

Dang, Yangyang; Zhong, Cheng; Zhang, Guodong; Ju, Dianxing; Wang, Lei; Xia, Shengqing; Xia, Haibing; Tao, Xutang

2016-01-01

substitute for the lead in the halides perovskites and solving the ambiguous crystal structures and phase transition of NH(CH3)3SnX3 (X = Cl, Br). Here, we report the bulk crystal growths and different crystal morphologies of orthorhombic hybrid perovskites

First-principle calculations for electronic properties of PuX3 (X=Rh, Pd, Pt)

International Nuclear Information System (INIS)

Tatetsu, Yasutomi; Maehira, Takahiro

2012-01-01

Energy band structures of PuX 3 (X=Rh, Pd, and Pt) are investigated by a relativistic linear augmented-plane-wave method with the exchange-correlation potential in a local density approximation. It is found in common that the energy bands in the vicinity of the Fermi level are mainly due to the hybridization between Pu 5f and X d electrons.

Synthesis and X-ray Structural Studies of a Substituted 2,3,4,5-Tetrahydro-1H-3-benzazonine and a 1,2,3,5-Tetrahydro-4,3-benzoxazonine

Directory of Open Access Journals (Sweden)

Timothy S. Bailey

2014-12-01

Full Text Available Using a common 1-(1-phenylethenyl-1,2,3,4-tetrahydroisoquinoline precursor to the required ylide or N-oxide intermediate, the Stevens [2,3] and analogous Meisenheimer [2,3] sigmatropic rearrangements have been applied to afford concise syntheses of phenyl -substituted representatives of each of the reduced 1H-3-benzazonine and 4,3-benzoxazonine systems, respectively. Single crystal X-ray structure determinations were employed to define the conformational characteristics for each ring type.

Neutron spectroscopy of the crystalline-electric-field in Nd{sub 1-x}Sr{sub x}MnO{sub 3} (x=0, 0.3) and PrMnO{sub 3}

Energy Technology Data Exchange (ETDEWEB)

Podelsnyak, A.; Mirmelstein, A. [Inst. for Metal Physics, Ekaterinburg (Russian Federation); Zolliker, M.; Furrer, A. [Paul Scherrer Inst. (PSI), Villigen (Switzerland)

1997-09-01

Ln{sub 1-x}A{sub {sub x}}MnO{sub 3} manganese perovskite are of interest because of their magnetic and transport properties. Inelastic neutron scattering has been employed to search for crystalline-electric-field (CEF) transitions in Nd{sub 1-x}Sr{sub x}MnO{sub 3} (x=0, 0.3) and PrMnO{sub 3} compounds. (author) 1 fig., 3 refs.

Highly sensitive and selective spectrofluorimetric determination of metoclopramide hydrochloride in pharmaceutical tablets and serum samples using Eu3+ ion doped in sol-gel matrix.

Science.gov (United States)

Attia, M S; Aboaly, M M

2010-06-30

A simple, sensitive and selective spectrofluorimetric method for the determination of Metoclopramide hydrochloride (MCP) is developed. The MCP can remarkably enhances the luminescence intensity of the Eu(3+) ion doped in sol-gel matrix at lambda(ex)=380 nm in DMSO at pH 8.7. The intensity of the emission band of Eu(3+) ion doped in sol-gel matrix increases due to energy transfer from MCP to Eu(3+) in the excited state. The enhancement of the emission band of Eu(3+) ion doped in sol-gel matrix at 617 nm was found to be directly proportional to the concentration of MCP with a dynamic range of 5 x 10(-9) - 1.0 x 10(-6) mol L(-1) and detection limit of 2.2 x10(-11) mol L(-1). Copyright 2010 Elsevier B.V. All rights reserved.

Magnetic correlations in UPt3 and U/sub 1-x/Th/sub x/Pt3

International Nuclear Information System (INIS)

Aeppli, G.; Bucher, E.; Goldman, A.I.; Shirane, G.; Broholm, C.; Kjems, J.K.

1988-01-01

Neutron scattering experiments on UPt 3 and U/sub 1-x/Th/sub x/Pt 3 are reviewed. At relatively high energies (/approximately/5 MeV), the magnetic fluctuation spectrum is modulated by the structure factor derived from short-range antiferromagnetic correlations where the two U ions in each unit cell are oppositely polarized. In contrast, at low energies (≤ 1 MeV), the diffuse inelastic scattering is associated with antiferromagnetic correlations where the unit cell is doubled. Nominally pure UPt 3 exhibits magnetic order with the wavevector corresponding to this doubling and a static moment of 0.02 +- 0.01 μ/sub B/. (U/sub 1-x/Th/sub x/)Pt 3 with x ≅ 0.05 exhibits ordering of the same type, but with a much larger static moment, 0.65 +- 0.1 μ/sub B/. Neutron scattering measurements on UPt 3 with implications for superconductivity are surveyed. 23 refs., 7 figs

Modeling the formation of cell-matrix adhesions on a single 3D matrix fiber.

Science.gov (United States)

Escribano, J; Sánchez, M T; García-Aznar, J M

2015-11-07

Cell-matrix adhesions are crucial in different biological processes like tissue morphogenesis, cell motility, and extracellular matrix remodeling. These interactions that link cell cytoskeleton and matrix fibers are built through protein clutches, generally known as adhesion complexes. The adhesion formation process has been deeply studied in two-dimensional (2D) cases; however, the knowledge is limited for three-dimensional (3D) cases. In this work, we simulate different local extracellular matrix properties in order to unravel the fundamental mechanisms that regulate the formation of cell-matrix adhesions in 3D. We aim to study the mechanical interaction of these biological structures through a three dimensional discrete approach, reproducing the transmission pattern force between the cytoskeleton and a single extracellular matrix fiber. This numerical model provides a discrete analysis of the proteins involved including spatial distribution, interaction between them, and study of the different phenomena, such as protein clutches unbinding or protein unfolding. Copyright © 2015 Elsevier Ltd. All rights reserved.

Carbon nanotube based 3-D matrix for enabling three-dimensional nano-magneto-electronics [corrected].

Directory of Open Access Journals (Sweden)

Jeongmin Hong

Full Text Available This letter describes the use of vertically aligned carbon nanotubes (CNT-based arrays with estimated 2-nm thick cobalt (Co nanoparticles deposited inside individual tubes to unravel the possibility of using the unique templates for ultra-high-density low-energy 3-D nano-magneto-electronic devices. The presence of oriented 2-nm thick Co layers within individual nanotubes in the CNT-based 3-D matrix is confirmed through VSM measurements as well as an energy-dispersive X-ray spectroscopy (EDS.

Convenient hydrothermal decomposition process for preparation of nanocrystalline mineral Cu3BiS3 and Pb1-xBi2x/3S

International Nuclear Information System (INIS)

Hu Junqing; Deng Bin; Wang Chunrui; Tang Kaibin; Qian Yitai

2003-01-01

Mineral nanocrystalline Cu 3 BiS 3 and Pb 1-x Bi 2x/3 S (or Bi 0.22 Pb 0.89 S 1.22 ) have been prepared at low synthetic temperature of 100-150 deg. C by convenient hydrothermal decomposition process. X-ray powder diffraction, transmission electron microscopy, X-ray photoelectron spectra, and element analysis were used to characterize and measure the samples. The as-prepared Cu 3 BiS 3 sample consisted of whisker-like particles with an average size of 50x10 nm 2 and the Pb 1-x Bi 2x/3 S sample displayed aggregative particles with size in the range of 30-50 nm. Preliminary results showed that the prepared precursors, reaction temperature and time played a role in the formation of the final products. A possible reaction mechanism was also discussed briefly

Local Structure of Mn in (La1-xHox)2/3Ca1/3MnO3 Studied by X-ray Absorption Fine Structure

International Nuclear Information System (INIS)

Pietnoczka, A.; Bacewicz, R.; Antonowicz, J.; Zalewski, W.; Pekala, M.; Drozd, V.; Fagnard, J.F.; Vanderbemden, P.

2010-01-01

Results of X-ray absorption fine structure measurements in manganites (La 1-x Ho x ) 2/3 Ca 1/3 MnO 3 with 0.15 3 is doped with a divalent element such as Ca 2+ , substituting for La 3+ , holes are induced in the filled Mn d orbitals. This leads to a strong ferromagnetic coupling between Mn sites. Ca ions in La 1-x Ca x MnO 3 introduce a distortion of the crystal lattice and mixed valence Mn ions (Mn 3+ and Mn 4+ ). On the other hand, in manganites (La 1-x Ho x ) 2/3 Ca 1/3 MnO 3 the substitution of La for Ho causes a lattice distortion and induces a disorder, which reduces a magnetic interaction. The ferromagnetic transition temperature and conductivity decrease very quickly with increasing x. The magnetic and transport properties of compounds depend on the local atomic structure around Mn ions. The information on the bond lengths and Debye-Waller factor are obtained from the extended X-ray absorption fine structure (EXAFS) data analysis. The charge state of Mn is determined from the position of the absorption edge in X-ray absorption near edge structure (XANES) data. XAFS results are in good agreement with magnetic characteristics of the studied materials. (authors)

Using 3 × 3 Matrix to Evaluate the Manufacturing Technology in Food Company

Directory of Open Access Journals (Sweden)

Ingaldi Manuela

2016-06-01

Full Text Available In order to produce goods of sufficient quality finding buyers in the market, a company must have an adequate knowledge of their production technology. Technologies and finished products at the same time will affect the position of the company in the market and hence its existence in this market. Therefore, it is so important for every company to determine the appropriate technological strategy. The 3 × 3 matrix is a very useful tool to do so. This matrix shows the relation between technological possibilities of the company and its position in the market. However, that requires changing the scale used in the matrix. In practice, this means that both those that have a positive impact on the company and those that have a negative impact on it can be included in the factors. The research was conducted in a food industry company. It turned out that the research company was located in field of the matrix marked as ‚Improve marketing’. It means that the company should put more emphasis on improving the factors related to its position in the market.

3-Loop massive O(T{sub 2}{sup F}) contributions to the DIS operator matrix element A{sub gg}

Energy Technology Data Exchange (ETDEWEB)

Ablinger, J.; Schneider, C. [Johannes Kepler Univ., Linz (Austria). Inst. for Symbolic Computation (RISC); Bluemlein, J.; Freitas, A. de [Deutsches Elektronen-Synchrotron (DESY), Zeuthen (Germany); Hasselhuhn, A.; Round, M. [Deutsches Elektronen-Synchrotron (DESY), Zeuthen (Germany); Johannes Kepler Univ., Linz (Austria). Inst. for Symbolic Computation (RISC); Manteuffel, A. von [Mainz Univ. (Germany). PRISMA Cluster of Excellence

2014-09-15

Contributions to heavy flavour transition matrix elements in the variable flavour number scheme are considered at 3-loop order. In particular a calculation of the diagrams with two equal masses that contribute to the massive operator matrix element A{sup (3)}{sub gg,Q} is performed. In the Mellin space result one finds finite nested binomial sums. In x-space these sums correspond to iterated integrals over an alphabet containing also square-root valued letters.

3D in situ observations of glass fibre/matrix interfacial debonding

DEFF Research Database (Denmark)

Martyniuk, Karolina; Sørensen, Bent F.; Modregger, Peter

2013-01-01

X-ray microtomography was used for 3D in situ observations of the evolution of fibre/matrix interfacial debonding. A specimen with a single fibre oriented perpendicular to the tensile direction was tested at a synchrotron facility using a special loading rig which allowed for applying a load...... transverse to the fibre. Three distinguishable damage stages were observed: (i) interfacial debond initiation at the free surface, (ii) debond propagation from the surface into the specimen and (iii) unstable debonding along the full length of the scanned volume. The high resolution microtomography provides...

Effect of γ- Ray Irradiation on the Solid Ionic Conductor of (Cul)x(Na3PO4)1-X Materials (x= 0.1 and x= 0.3)

International Nuclear Information System (INIS)

Purwanto, P.

2008-01-01

Study on the effect of γ- ray irradiation on solid state conductor (Cul) x (Na 3 PO 4 ) 1-X have been done. The solid ionic conductor of (Cul) x (Na 3 PO 4 ) 1-X (x= 0.1 and x= 0.3) had been made by mixing Cul with Na 3 PO 4 by formula of (Cul) x (Na 3 PO 4 ) 1-X where x= 0.1 and x= 0.3 then pressed with 48.26 x 10 6 N/m 2 into pellete in diametre 1.5 x 10 - 2 m. The solid ionic conductor was then γ- ray irradiated with dose of 5 to 30 kGy. The result showed that the structure of (Cul) x (Na 3 PO 4 ) 1-X was Cul and Na 3 PO 4 . Crystall lattice strain of (Cul) x (Na 3 PO 4 ) 1-X were measured stable against the influence of radiation. The conductivity measurement of (Cul) x (Na 3 PO 4 ) 1-X was carried out by LCR at the frequence of 0.1 Hz to 100 kHz. The result showed that the conductivities of (Cul) x (Na 3 PO 4 ) 1-X after irradiation were increasing with radiation dose. (author)

Synthesis, structural and microwave dielectric properties of Al2W3-xMoxO12 (x = 0-3) ceramics

International Nuclear Information System (INIS)

Surjith, A.; James, Nijesh K.; Ratheesh, R.

2011-01-01

Highlights: → Solid state synthesis of phase pure Al 2 W 3-x Mo x O 12 (x = 0-3) compositions. → Sintering studies of Al 2 W 3-x Mo x O 12 (x = 0-3) ceramics. → Structural and microstructural evaluation using powder X-ray diffraction and SEM studies. → Microwave dielectric property evaluation of Al 2 W 3-x Mo x O 12 (x = 0-3) ceramics through Hakki and Coleman post resonator and cavity perturbation techniques. → Structure-property correlation through Laser Raman studies. - Abstract: Low dielectric ceramics in the Al 2 W 3-x Mo x O 12 (x = 0-3) system have been prepared through solid state ceramic route. The phase purity of the ceramic compositions has been studied using powder X-ray diffraction (XRD) studies. The microstructure of the sintered ceramics was evaluated by Scanning Electron Microscopy (SEM). The crystal structure of the ceramic compositions as a result of Mo substitution has been studied using Laser Raman spectroscopy. The microwave dielectric properties of the ceramics were studied by Hakki and Coleman post resonator and cavity perturbation techniques. Al 2 Mo x W 3-x O 12 (x = 0-3) ceramics exhibited low dielectric constant and relatively high unloaded quality factor. The temperature coefficient of resonant frequency of the compositions is found to be in the range -41 to -72 ppm/deg. C.

On the growth of CH3NH3PbI3-xClx single crystal and characterization

Science.gov (United States)

Su, J.; Wang, W. F.; Lei, Y.; Zhang, L.; Xu, L. H.; Wang, D.; Lu, D.; Bai, Y.

2018-05-01

In this paper, CH3NH3PbI3-xClx crystal was grown by solution cooling method with CH3NH3I and PbCl2 as raw materials. Lead compounds and CH3NH3PbI3-xClx crystal with size about 6 mm × 4 mm × 2 mm were obtained. The chemical reactions with different CH3NH3I/PbCl2 ratios were analyzed. XPS shows the content of chlorine in CH3NH3PbI3-xClx is about 0.91%. PXRD, FT-IR, Raman and absorbance spectra were used to study the structure and optical properties of CH3NH3PbI3-xClx by comparing with CH3NH3PbI3 crystal. The CH3NH3PbI3-xClx crystal grown is of tetragonal structure with the lattice constants a = b = 8.8165 Å, c = 12.7920 Å and the bandgap value of 1.57 eV.

CH3NH3Pb1-xMgxI3 perovskites as environmentally friendly photovoltaic materials

Science.gov (United States)

Zhang, Y. D.; Feng, J.

2018-01-01

In an effort to reduce the toxicity of Pb in perovskite solar cells, the band structures, electron and hole effective masses, and electronic and optical properties of the novel perovskites CH3NH3Pb1-xMgxI3 were predicted using density functional theory with the scalar relativistic generalized gradient approximation. The calculation results indicated that the introduction of the Mg component caused the band gaps of the CH3NH3Pb1-xMgxI3 compounds to exceed that of CH3NH3PbI3. The calculated absorption coefficients of the CH3NH3PbI3 and CH3NH3Pb1-xMgxI3 perovskites revealed that substituting 12.5 mol % of the Pb in CH3NH3PbI3 with Mg had little effect on the absorption ability. Surprisingly, it was also found that CH3NH3Pb0.75Mg0.25I3 retained up to 83% of the absorption performance relative to CH3NH3PbI3. This indicates that the amount of toxic Pb used in perovskite solar cells could be reduced by a quarter while retaining over 80% of the light-absorbing ability. In general, these novel CH3NH3Pb1-xMgxI3 (x ≤ 0.25) perovskites represent promising candidates for environmentally friendly light-harvesting materials for use in solar cells.

Gold-coated iron nanoparticles in transparent Si3N4 matrix thin films

Science.gov (United States)

Sánchez-Marcos, J.; Céspedes, E.; Jiménez-Villacorta, F.; Muñoz-Martín, A.; Prieto, C.

2013-06-01

A new method to prepare thin films containing gold-coated iron nanoparticles is presented. The ternary Fe-Au-Si3N4 system prepared by sequential sputtering has revealed a progressive variation of microstructures from Au/Fe/Au/Si3N4 multilayers to iron nanoparticles. Microstructural characterization by transmission electron microscopy, analysis of the magnetic properties and probing of the iron short-range order by X-ray absorption spectroscopy confirm the existence of a gold-coated iron nanoparticles of 1-2 nm typical size for a specific range of iron and gold contents per layer in the transparent silicon nitride ceramic matrix.

Microstructure and mechanical properties of stir cast ZX51/Al2O3p magnesium matrix composites

International Nuclear Information System (INIS)

Rahmany-Gorji, Reza; Alizadeh, Ali; Jafari, Hassan

2016-01-01

Magnesium matrix composites can overcome the limitations of magnesium and its alloys. This paper investigates the effect of adding Al 2 O 3 microparticles on microstructure and mechanical response of ZX51 alloy-matrix composites. Stir casting process was chosen due largely to its low cost to fabricate the novel ZX51/Al 2 O 3 p composites. Scanning electron microscopy, energy dispersive spectroscopy, and X-ray diffractometry were used in order to analyze the microstructure of as-cast composites. Tension, compression, and Brinell hardness tests were performed to determine mechanical properties of the composites. It was revealed that the microstructure of matrix alloy is composed of α-Mg grains and (α-Mg+Ca 2 Mg 6 Zn 3 ) eutectic mixture distributed predominantly along grain boundaries. The addition of Al 2 O 3 p brought about a marked grain refinement and also introduced slight amounts of porosity. The results showed that with increasing volume percentage of Al 2 O 3 p, hardness and yield strength increase while tensile strength, compressive strength, and ductility decrease; in consequence, toughness decreases as well.

Czochralski growth and optical properties of Li 6Gd 1-xEu x(BO 3) 3 ( x=0-1) single crystals

Science.gov (United States)

Yavetskiy, R. P.; Dolzhenkova, E. F.; Dubovik, M. F.; Korshikova, T. I.; Tolmachev, A. V.

2005-04-01

It was shown that a continuous series of Li 6Gd 1-xEu x(BO 3) 3 solid solutions exist within the whole concentration range ( x=0-1). Li 6Gd 1-xEu x(BO 3) 3 ( x=0-0.03; 1) single crystals up to 25 mm in length and up to 20 mm in diameter have been grown by the Czochralski method. The structural perfection of the crystals has been estimated from etch patterns and XPA analysis results. The optical absorption and thermally stimulated luminescence of the grown crystals has been studied.

First principles investigation of half-metallicity and spin gapless semiconductor in CH3NH3Cr x Pb1- x I3 mixed perovskites

Science.gov (United States)

Huang, H. M.; Zhu, Z. W.; Zhang, C. K.; He, Z. D.; Luo, S. J.

2018-04-01

The structural, electronic and magnetic properties of organic-inorganic hybrid mixed perovskites CH3NH3Cr x Pb1- x I3 ( x = 0.25, 0.50, 0.75, 1.00) in cubic, tetragonal and orthorhombic phases have been investigated by first-principles calculation. The results indicate that the tetragonal CH3NH3Cr0.75Pb0.25I3 is a spin gapless semiconductor with Curie temperature of 663 K estimated using mean field approximation. All other CH3NH3Cr x Pb1- x I3 mixed perovskites are half-metallic ferromagnets together with 100% spin polarization, and their total magnetic moment are 4.00, 8.00, 12.00 and 16.00 µB per unit cell for x = 0.25, 0.50, 0.75 and 1.00, respectively. The effect of , and orientation of organic cation CH3NH3 + on the electronic properties of CH3NH3Cr0.50Pb0.50I3 was investigated. The results show that the CH3NH3 + in different orientations have a slight effect on the lattice constants, the energy gap in minority-spin states, half-metallic gap, local magnetic moment, and Curie temperature.

Electrical conductivity studies in (Ag3AsS3)x(As2S3)1-x superionic glasses and composites

Science.gov (United States)

Studenyak, I. P.; Neimet, Yu. Yu.; Kranjčec, M.; Solomon, A. M.; Orliukas, A. F.; Kežionis, A.; Kazakevičius, E.; Šalkus, T.

2014-01-01

Compositional, frequency, and temperature studies of impedance and electrical conductivity in (Ag3AsS3)x(As2S3)1-x superionic glasses and composites were performed. Frequency range from 10 Hz to 3 × 109 Hz and temperature interval 300-400 K were used for the measurements. Compositional dependences of electrical conductivity and activation energy are analyzed; the most substantial changes are observed with the transition from (Ag3AsS3)0.4(As2S3)0.6 glass to (Ag3AsS3)0.5(As2S3)0.5 composite. With increase of Ag3AsS3 content, the investigated materials are found to have crystalline inclusions and show the two-phase composite nature. Addition of Ag3AsS3 leads to the increase of electrical conductivity whereas the activation energy decreases.

X-ray tomography: Biological cells in 3-D at better than 50 nm resolution

International Nuclear Information System (INIS)

Larabell, C.; Le Gros, M.

2004-01-01

Full text: X-ray microscopy can be used to image whole, hydrated, specimens with a spatial resolution 5-10 times better than that obtained using visible light microscopy. X-ray imaging at photon energies below the K- absorption edge of oxygen, referred to as the water window, exploits the strong natural contrast for organic material embedded in a mostly water matrix. With a transmission X-ray microscope using Fresnel zone plate optics, specimens up to 10 microns thick can be examined. The highest X-ray transmission in hydrated samples is obtained at a wavelength of 2.4 nm but, due to the low numerical aperture of zone plate lenses operated in st order diffraction mode the structures resolved are much larger than the X-ray wavelength. Because of the low NA of X-ray lenses (NA=0.05), combined with the effect of polychromatic illumination and a wavelength dependant focal length, the effective depth of ld is large (6-10 microns). The experiments presented here were performed at the Advanced Light Source using the full ld transmission X-ray microscope, XM-1. This microscope employs a bend magnet X-ray source and zone plate condenser and objective lenses. The condenser zone plate acts as a monochromator and the X-ray images are recorded directly on a cooled, back-thinned 1024x1024 pixel CCD camera. The sample holder was a rotationally symmetric glass tube; the region containing the sample was 10 microns in diameter with a wall thickness of 200 nm. Live yeast cells were loaded into the tube, rapidly frozen by a blast of liquid nitrogen-cooled helium gas, and maintained at 140 deg C by a steady flow of cold helium. The image sequence spanned 180 deg and consisted of 45 images spaced by 4 deg. The images were aligned to a common axis and computed tomographic reconstruction was used to obtain the 3-D X-ray linear absorption coefficient. Volume rendering and animation of reconstructed data was performed using the 3-D program, Amira. Acquisition time for 90 images was 3 min

Hard X-ray observation of cygnus X-3

International Nuclear Information System (INIS)

Kendziorra, E.; Staubert, R.; Reppin, C.; Pietsch, W.; Truemper, J.; Voges, W.

1979-05-01

During a balloon observation on October 18, 1977 the high energy X-ray spectrum (20 - 90 keV) of Cyg X-3 has been measured with high statistical accuracy. It is found to be consistent with a thermal bremsstrahlung spectrum with kT = 17.5 +3.1/-2.6 keV or a power law Esup(γ) of the differential photon flux spectrum with γ=3.6 +-0.3. The extrapolation of the observed spectrum to approximately 100 MeV yields a gamma ray intensity which is at least three orders of magnitude below the intensity found by SAS-2 (Lamb et al. 1977). This indicates that the overall spectral behaviour of Cygnus X-3 is much different from that of the Crab- and Vela-pulsar. (orig.) [de

X-ray and neutron diffraction study of alums. Pt. 2 and 3

International Nuclear Information System (INIS)

Abdeen, A.M.; Will, G.; Schaefer, W.; Kirfel, A.; Bargouth, M.O.; Recker, K.; Weiss, A.

1981-01-01

The crystal structure of the alums, (NH 3 CH 3 )Al(SO 4 ) 2 x 12 H 2 0 and (NH 4 )AL(SO 4 ) 2 x 12 H 2 0, has been determined and refined from X-ray and neutron diffraction data. The compounds crystallize cubic in space group Pa3 (Z = 4). The positional and thermal parameters of all atoms including hydrogens have been refined by full matrix least-sqares analysis resulting in Rsub(w) values from the X-ray and neutron data of 0.030 and 0.029 respectively for the methylammonium alum and of 0.024 and 0.014 respectively for the ammonium alum. The atoms of the cation groups (NH 3 CH 3 ) + and (NH 4 ) + are distributed on 8(c) and 24(d) positions in two orientations of equal probability on and around the [111] direction related to each other by an inversion centre. The disorder in the cation groups is explained by a quantized rotation. Disorder in the sulfate groups has been determined to 4.2% for the methylammonium alum and to about 17% for the ammonium alum. The disordered sulfate tetrahedra are distorted and in a reversed orientation along the threefold axis. The system of the hydrogen bonds is discussed. (orig.)

Thermal expansion of Cr2xFe2-2xMo3O12, Al2xFe2-2xMo3O12 and Al2xCr2-2xMo3O12 solid solutions

International Nuclear Information System (INIS)

Ari, M.; Jardim, P.M.; Marinkovic, B.A.; Rizzo, F.; Ferreira, F.F.

2008-01-01

The transition temperature from monoclinic to orthorhombic and the thermal expansion of the orthorhombic phase were investigated for three systems of the family A 2 M 3 O 12 : Cr 2x Fe 2-2x Mo 3 O 12 , Al 2x Fe 2-2x Mo 3 O 12 and Al 2x Cr 2-2x Mo 3 O 12 . It was possible to obtain a single-phase solid solution in all studied samples (x=0, 0.1, 0.3, 0.5, 0.7, 0.9 and 1). A linear relationship between the transition temperature and the fraction of A 3+ cations (x) was observed for each system. In all orthorhombic solid solutions studied here the observed thermal expansion was anisotropic. These anisotropic thermal expansion properties of crystallographic axes a, b and c result in a low positive or near-zero overall linear coefficient of thermal expansion (α l =α V /3). The relationship between the size of A 3+ cations in A 2 M 3 O 12 and the coefficient of thermal expansion is discussed. Near-zero thermal expansion of Cr 2 Mo 3 O 12 is explained by the behavior of Cr-O and Mo-O bond distances, Cr-Mo non-bond distances and Cr-O-Mo bond angles with increasing temperature, estimated by Rietveld analysis of synchrotron X-ray powder diffraction data. - Graphical abstract: In this figure, all published overall linear coefficients of thermal expansion for orthorhombic A 2 M 3 O 12 family obtained through diffraction methods as a function of A 3+ cation radii size, together with dilatometric results, are plotted. Our results indicate that Cr 2 Mo 3 O 12 does not exactly follow the established relationship

Infrared, radio, and x-ray observations of Cygnus X-3

International Nuclear Information System (INIS)

Becklin, E.E.; Hawkins, F.J.; Mason, K.O.; Matthews, K.; Neugebauer, G.; Packman, D.; Sanford, P.W.; Schupler, B.; Stark, A.; Wynn-Williams, C.G.

1974-01-01

The x-ray source Cygnus X-3 has been interpreted as being a binary system on the basis of extensive x-ray observations of periodic variability. At radio wavelengths, the source displays erratic outbursts. Cyg x-3 has not been detected visually but at infrared wavelengths periodic variations in phase with the x-ray variations have been reported. Infrared, x-ray and radio observations of Cyg X-3 made during 1973 through 1973 October are presented. (U.S.)

Phases of variable composition in the system Ba3-xSrxEr(BO3)3 (0≤x≤3.0)

International Nuclear Information System (INIS)

Khamaganova, T.N.

2008-01-01

The possibility of preparing two series of solid solutions in the system Ba 3-x Sr x Er(BO 3 ) 3 (0 ≤ x ≤ 3.0), crystallizing in different structural types, was examined. Samples of the phases of variable composition were synthesized by solid-phase reactions over the temperature range 500-1000 deg C, and their X-ray diffraction characteristics were determined. It is found that the triple phases prepared form two series of substitutional solid solutions in the system studied [ru

Effect of Ca2+ Ions on Electrical Properties of Ba1-x Ca x Ti0.90Sn0.10O3-0.05Y2O3 Ceramics

Science.gov (United States)

Chen, Zhi-hui; Li, Zhi-wei; Ding, Jian-ning; Zhao, Tian-xiang; Qiu, Jian-hua; Zhu, Ke-qian; Xu, Jiu-jun; Zhang, Bing

2018-03-01

Ba1-x Ca x Ti0.90Sn0.10O3-0.05Y2O3 (BCTSY) lead-free piezoceramics with x = 0.02 to 0.10 have been fabricated by solid-state sintering method at 1420°C. The effects of Ca2+ ions on the microstructure and electrical properties of the samples were studied. X-ray diffraction analysis showed that all samples possessed pure perovskite structure with Ca2+ ions diffused into the matrix lattice. The rhombohedral phase and tetragonal phase coexisted in the composition range of 0.02 ceramic became more homogeneous with addition of Ca2+ ions, and the average grain size of the samples decreased from 97 μm (x = 0.02) to 18 μm (x = 0.10). Addition of Ca2+ remarkably improved the piezoelectric properties, enhanced the dielectric frequency dispersion, and increased the Curie temperature of the ceramics. The piezoelectric properties of the ceramics were optimized at x = 0.04 with d 33 and K p values of 579 pC/N and 52.7%, respectively.

Effect of nano size 3% wt TaC particles dispersion in two different metallic matrix composites

International Nuclear Information System (INIS)

Gomes, U.U.; Oliveira, L.A.; Souza, C.P.; Menezes, R.C.; Furukava, M.; Torres, Y.

2009-01-01

This work studies the characteristics of two different metallic matrixes composites, ferritic and austenitic steels, reinforced with 3% wt nano size tantalum carbide by powder metallurgy. The starting powders were characterized by X-ray diffraction (XRD) and scanning electron microscopy (SEM). The effects of the nano sized carbide dispersion on the matrix microstructures and its consequences on the mechanical properties were identified. The preliminary results showed that the sintering were influenced by morphology and the distribution of carbide and the alloys. (author)

Mean deformation metrics for quantifying 3D cell–matrix interactions without requiring information about matrix material properties

Science.gov (United States)

Stout, David A.; Bar-Kochba, Eyal; Estrada, Jonathan B.; Toyjanova, Jennet; Kesari, Haneesh; Reichner, Jonathan S.; Franck, Christian

2016-01-01

Mechanobiology relates cellular processes to mechanical signals, such as determining the effect of variations in matrix stiffness with cell tractions. Cell traction recorded via traction force microscopy (TFM) commonly takes place on materials such as polyacrylamide- and polyethylene glycol-based gels. Such experiments remain limited in physiological relevance because cells natively migrate within complex tissue microenvironments that are spatially heterogeneous and hierarchical. Yet, TFM requires determination of the matrix constitutive law (stress–strain relationship), which is not always readily available. In addition, the currently achievable displacement resolution limits the accuracy of TFM for relatively small cells. To overcome these limitations, and increase the physiological relevance of in vitro experimental design, we present a new approach and a set of associated biomechanical signatures that are based purely on measurements of the matrix's displacements without requiring any knowledge of its constitutive laws. We show that our mean deformation metrics (MDM) approach can provide significant biophysical information without the need to explicitly determine cell tractions. In the process of demonstrating the use of our MDM approach, we succeeded in expanding the capability of our displacement measurement technique such that it can now measure the 3D deformations around relatively small cells (∼10 micrometers), such as neutrophils. Furthermore, we also report previously unseen deformation patterns generated by motile neutrophils in 3D collagen gels. PMID:26929377

A Computational Study of Chalcogen-containing H2 X…YF and (CH3 )2 X…YF (X=O, S, Se; Y=F, Cl, H) and Pnicogen-containing H3 X'…YF and (CH3 )3 X'…YF (X'=N, P, As) Complexes.

Science.gov (United States)

McDowell, Sean A C; Buckingham, A David

2018-04-20

A computational study was undertaken for the model complexes H 2 X…YF and (CH 3 ) 2 X…YF (X=O, S, Se; Y=F, Cl, H), and H 3 X'…YF and (CH 3 ) 3 X'…YF (X'=N, P, As), at the MP2/6-311++G(d,p) level of theory. For H 2 X…YF and H 3 X'…YF, noncovalent interactions dominate the binding in order of increasing YF dipole moment, except for H 3 As…F 2 , and possibly H 3 As…ClF. However, for the methyl-substituted complexes (CH 3 ) 2 X…YF and (CH 3 ) 3 X'…YF the binding is especially strong for the complexes containing F 2 , implying significant chemical bonding between the interacting molecules. The relative stability of these complexes can be rationalized by the difference in the electronegativity of the X or X' and Y atoms. © 2018 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

CH3NH3Pb1−xMgxI3 perovskites as environmentally friendly photovoltaic materials

Directory of Open Access Journals (Sweden)

Y. D. Zhang

2018-01-01

Full Text Available In an effort to reduce the toxicity of Pb in perovskite solar cells, the band structures, electron and hole effective masses, and electronic and optical properties of the novel perovskites CH3NH3Pb1−xMgxI3 were predicted using density functional theory with the scalar relativistic generalized gradient approximation. The calculation results indicated that the introduction of the Mg component caused the band gaps of the CH3NH3Pb1−xMgxI3 compounds to exceed that of CH3NH3PbI3. The calculated absorption coefficients of the CH3NH3PbI3 and CH3NH3Pb1−xMgxI3 perovskites revealed that substituting 12.5 mol % of the Pb in CH3NH3PbI3 with Mg had little effect on the absorption ability. Surprisingly, it was also found that CH3NH3Pb0.75Mg0.25I3 retained up to 83% of the absorption performance relative to CH3NH3PbI3. This indicates that the amount of toxic Pb used in perovskite solar cells could be reduced by a quarter while retaining over 80% of the light-absorbing ability. In general, these novel CH3NH3Pb1−xMgxI3 (x ≤ 0.25 perovskites represent promising candidates for environmentally friendly light-harvesting materials for use in solar cells.

A giant radio flare from Cygnus X-3 with associated γ-ray emission: The 2011 radio and γ-ray flare of Cyg X-3

International Nuclear Information System (INIS)

Corbel, S.; Dubus, G.; Tomsick, J. A.; Szostek, A.

2012-01-01

With frequent flaring activity of its relativistic jets, Cygnus X-3 (Cyg X-3) is one of the most active microquasars and is the only Galactic black hole candidate with confirmed high-energy γ-ray emission, thanks to detections by Fermi Large Area Telescope (Fermi/LAT) and AGILE. In 2011, we observed Cyg X-3 in order to transit to a soft X-ray state, which is known to be associated with high-energy γ-ray emission. We present the results of a multiwavelength campaign covering a quenched state, when radio emission from Cyg X-3 is at its weakest and the X-ray spectrum is very soft. A giant (~20 Jy) optically thin radio flare marks the end of the quenched state, accompanied by rising non-thermal hard X-rays. Fermi/LAT observations (E≥ 100 MeV) reveal renewed γ-ray activity associated with this giant radio flare, suggesting a common origin for all non-thermal components. In addition, current observations unambiguously show that the γ-ray emission is not exclusively related to the rare giant radio flares. A three-week period of γ-ray emission is also detected when Cyg X-3 was weakly flaring in radio, right before transition to the radio quenched state. There were no γ-rays observed during the ~1-month long quenched state, when the radio flux is weakest. These results suggest transitions into and out of the ultrasoft X-ray (radio-quenched) state trigger γ-ray emission, implying a connection to the accretion process, and also that the γ-ray activity is related to the level of radio flux (and possibly shock formation), strengthening the connection to the relativistic jets.

Legendre polynomial modeling for vibrations of guided Lamb waves modes in [001]c, [011]c and [111]c polarized (1-x)Pb(Mg1/3Nb2/3)O3-xPbTiO3 (x = 0.29 and 0.33) piezoelectric plates: Physical phenomenon of multiple intertwining of An and Sn modes

Science.gov (United States)

Othmani, Cherif; Takali, Farid; Njeh, Anouar

2017-12-01

Guided wave devices have recently become one of the most important applications in the industry because such waves are directly related to applications in sensor technology, chemical sensing, agricultural science, fields of bio-sensing and surface acoustic wave (SAW) devices that are used in electronic filters and signal processing. On that account, this numerical investigation aims to study the propagation behavior of guided Lamb waves in a (1-x)Pb(Mg1/3Nb2/3)O3- x PbTiO3 [PMN- x PT] ( x=0.29 or 0.33) piezoelectric single crystal plate. In fact, the PMN- xPT ( x=0.29 or 0.33) piezoelectric crystals are being polarized along [001]c, [011]c and [111]c of the cubic reference directions so that the macroscopic symmetries are tetragonal 4 mm, orthogonal mm2 and rhombohedral 3 m, respectively. Both open- and short-circuit conditions are considered. Here, the Legendre polynomial method is proposed to solve the guided Lamb waves equations. The validity of the proposed method is illustrated by comparison with the ordinary differential equation (ODE). The convergence of this method is discussed. Consequently, the converged results are obtained with very low truncation order M . This constitutes a major advantage of the present method when compared with the other matrix methods. There is cross-crossings among multiple modes for both symmetric ( Sn) and the anti-symmetric ( An) guided Lamb waves propagation. A displacement field has been illustrated to judge whether Sn and An modes cross with each other. Moreover, electric displacement, stress field and electric potential for the open-circuit case were presented for both S0 and A0 Lamb modes.

Luminescence of Ce3+ ions in Y3Al5O12 - Y3Ga5O12 solid solution

International Nuclear Information System (INIS)

Zorenko, Yu.V.; Nazar, I.V.; Limarenko, L.N.; Pashkovskij, M.V.

1996-01-01

Regularities of changes in spectral and energetic characteristics of the Ce 3+ ions radiation in the Y 3 Al 5-x Ga x O 12 solid solutions, related to change in the matrix crystal field force and dissipation of the luminescence excitation energy because of transfers between the valency zone ceiling and the Ce 3+ excited ion basis state are obtained. 9 refs., 3 figs., 1 tab

Effect of x-ray irradiation on the dentin matrix formation

Energy Technology Data Exchange (ETDEWEB)

You, Dong Soo [Dept. of Radiology, College of Dentistry, Seoul National University, Seoul (Korea, Republic of); Chang, Won Sik [Dept. of Prosthodontics, College of Dentistry, Seoul National University, Seoul (Korea, Republic of); Whang, Sung Myung [Dept. of Oral Antomy, College of Dentistry, Seoul National University, Seoul (Korea, Republic of)

1976-11-15

The authors has observed the effect of X-ray irradiation on the dentin matrix formation of the albino rat fetuses. The lower abdomen of the pregnant rats were exposed to X-ray on the 9 1/2th day of gestation, respectively 150, 250 and 350 rads. The fetuses of the right side of the same pregnant rats which were not exposed to X-ray were as controls. The results were as follows: 1) In the 150 rads irradiated fetuses, predentin formation was identical with control groups, but the arrangement of od ontoblasts was distorted, subodontoblastic layer was condensed with pulp cells, and blood capillaries were enlarged. 2) In the 250 rads irradiation, dentin matrix was imperfect or osteodentin was occurred. Short columnar or cuboidal od ontoblasts were presented and pulp cells were dispersed. Blood capillaries were congested. 3) 350 rads irradiated fetuses showed osteodentin matrix and numerous degenerated odontoblasts. Their dental papilla sh owed reticular atrophy and enlarged capillary.

Phonon dynamics of the Sn/Ge(111)-(3 x 3) surface

International Nuclear Information System (INIS)

Farias, D.; Kaminski, W.; Lobo, J.; Ortega, J.; Hulpke, E.; Perez, R.; Flores, F.; Michel, E.G.

2004-01-01

We present a theoretical and experimental study on the phonon dynamics of the low-temperature Sn/Ge(111)-(3 x 3) structure. High-resolution helium atom scattering (HAS) data show that, besides the Rayleigh wave, there are three surface phonon branches with low dispersion related to the (3 x 3) surface phase. Their energies are approximately 6.5, 4, and 3meV at the Γ-bar point. In addition, we detect phonon peaks in the Q range 0.4-0.5A -1 at ∼2meV, which correspond to (3 x 3) folding of the Rayleigh wave. Ab initio DFT-GGA total energy calculations have been performed to determine the frequencies associated with the vertical displacements of the three Sn atoms in the unit cell. The values obtained are in good agreement with the experiment

Matrix models as non-commutative field theories on R3

International Nuclear Information System (INIS)

Livine, Etera R

2009-01-01

In the context of spin foam models for quantum gravity, group field theories are a useful tool allowing on the one hand a non-perturbative formulation of the partition function and on the other hand admitting an interpretation as generalized matrix models. Focusing on 2d group field theories, we review their explicit relation to matrix models and show their link to a class of non-commutative field theories invariant under a quantum-deformed 3d Poincare symmetry. This provides a simple relation between matrix models and non-commutative geometry. Moreover, we review the derivation of effective 2d group field theories with non-trivial propagators from Boulatov's group field theory for 3d quantum gravity. Besides the fact that this gives a simple and direct derivation of non-commutative field theories for the matter dynamics coupled to (3d) quantum gravity, these effective field theories can be expressed as multi-matrix models with a non-trivial coupling between matrices of different sizes. It should be interesting to analyze this new class of theories, both from the point of view of matrix models as integrable systems and for the study of non-commutative field theories.

Effect of matrix constitution on interface of aluminium/δ-Al2O3 and strength of metal matrix composites

International Nuclear Information System (INIS)

Johansson, P.; Hutchinson, B.; Savage, S.J.

1992-06-01

Aluminium based fiber composites have been made by squeeze casting. The 'saffil' pre-forms used in the work employed aluminium oxide binder or silica binder. Two families of alloys have been used based either on high purity aluminium or 3% copper containing alloys. These were both alloyed with a range of magnesium contents from 0.1% to 5% with the aim of varying the degree of reaction and bonding between the matrix and the reinforcing fibres. Studies of macro- and micro structures have been performed as well as non-destructive testing by X-ray radiography. Tensile testing, three point bend tests on notched bars and wetting studies in a wetting balance are also included in the investigation. The structure of the squeeze cast products shows different zones. The extension and appearance of the zones are dependent on the alloy constitution. In general the surface of the casting have small equiaxed grains. This surface zone is replaced by a columnar grain zone which, in the center, transforms to an equiaxed crystal zone. Defects such as pores, fibre-free zones, and 'pockets' in the interface matrix/fiber have been found. Of these defects, only pores can be detected by X-ray radiography. Evaluation of tensile testing shows a relatively large scatter of results. The results reveal a dominant role of matrix composition on strength level. For the 20 vol% reinforced metals, with performs with silica binder, the maximum measured elongation was 3.5%. With alumina binder approximately half of the above mentioned ductility is obtained. The use of grain-refiner, Al-5Ti-B, decreases the ductility of the composite below 2%, independent of the type of binder. From 3-point bend tests fracture energies are estimated to vary between 0.3 and 0.6 Joule. The toughness is low. Studies of the wetting between pieces of ceramic pre-forms and molten Al-2Mg show that generally the wetting is poor. At the same time, the wettability of d-alumina with silicon oxide as binding medium was slightly

Electron microscopy and diffraction of barium-lanthanum ferrites: Ba/sub x/La/sub 1-x/FeO/sub 3-y/

Energy Technology Data Exchange (ETDEWEB)

Parras, M.; Vallet-Regi, M.; Gonzalez-Calbet, J.M.; Alario-Franco, M.; Grenier, J.C.

1988-05-01

The system formed by Ba/sub 2/Fe/sub 2/O/sub 5/ and LaFeO/sub 3/ has been studied at the microstructural level. Four different phases, which are metrical multiples of the perovskite cubic cell, appear as a function of the Ba/La ratio. Their microstructure ranges from three-dimensional multitwinning, as in LaFeO/sub 3/, to an apparently stoichiometric line phase of Ba/sub 2/Fe/sub 2/O/sub 5/ composition with parameters a = 23.40(1) A, b = 11.71(1) A, c = 7.05(1) A, and ..beta.. = 98/sup 0/3(1)'. For 0 < x < 0.25, cubic regions appear within a LaFeO/sub 3/ matrix. When x = 0.33, a double perovskite cell is intergrown with a single one. Such a single cubic perovskite is the only phase obtained in the 0.33 < x < 0.66 range.

Temperature dependent dielectric and magnetic properties of GdFe{sub 1−x}Ni{sub x}O{sub 3} (0.0 ≤ x ≤ 0.3) orthoferrites

Energy Technology Data Exchange (ETDEWEB)

Kaur, Pawanpreet, E-mail: merry2286@gmail.com; Sharma, K. K., E-mail: kknitham@gmail.com; Pandit, Rabia [Department of Physics, National Institute of Technology, Himachal Pradesh, Hamirpur 177005 (India); Kumar, Ravi [Centre for Material Science and Engineering, National Institute of Technology, Himachal Pradesh, Hamirpur 177005 (India); Kotnala, R. K.; Shah, Jyoti [National Physical Laboratory, New Delhi 110012 (India)

2014-06-14

The polycrystalline samples of GdFe{sub 1−x}Ni{sub x}O{sub 3} (x = 0.0, 0.1, 0.2, 0.3) orthoferrites are synthesized via solid state reaction route. The Rietveld fitted X-ray diffraction patterns confirm the formation of orthorhombic phase with Pbnm space group for all the samples. The dielectric measurements reveal an enhancement in dielectric constant and tangent loss with increase in both temperature as well as Nickel (Ni) substitution. Dielectric studies are also in support with the induction of delocalized charge carriers in the GdFeO{sub 3} matrix with increasing Ni doping. Magnetization versus applied field study shows the non-saturating hysteresis curves suggesting the canted type antiferromagnetic behavior in the considered orthoferrites. Moreover, the observed magnetic behavior is complex and the doping affects the magnitude of magnetization differently at 300 K and 80 K. It has further been noticed that the incorporated Ni{sup 3+} ions enhances the symmetry of the magnetization curves. The as-prepared samples may find their applications in the decoupling capacitors.

Li3-xNaxV2(PO4)3 (0≤x≤3): Possible anode materials for rechargeable lithium-ion batteries

International Nuclear Information System (INIS)

Wang, Pengfei; Shao, Lianyi; Qian, Shangshu; Yi, Ting-Feng; Yu, Haoxiang; Yan, Lei; Li, Peng; Lin, Xiaoting; Shui, Miao; Shu, Jie

2016-01-01

Highlights: • Li 3-x Na x V 2 (PO 4 ) 3 (0 ≤ x ≤ 3) series are firstly evaluated as anode materials. • Li 3-x Na x V 2 (PO 4 ) 3 anodes show lithium storage activity in 1.0–3.0 V. • The lithium storage capability of different Li 3-x Na x V 2 (PO 4 ) 3 is compared. • Structural reversibility of Li 3-x Na x V 2 (PO 4 ) 3 is studied by in-situ XRD. - Abstract: In this paper, a series of Li 3-x Na x V 2 (PO 4 ) 3 (0 ≤ x ≤ 3) are prepared by a solid state reaction and systematically evaluated as anode materials for lithium-ion batteries. Structural analysis shows that the phase structure of Li 3-x Na x V 2 (PO 4 ) 3 changes along with the evolution of Na content. Charge-discharge tests exhibit that Li 3 V 2 (PO 4 ) 3 shows the highest initial charge specific capacity as high as 88.3 mAh g −1 among all the seven samples, and the reversible capacity is kept at 68.3 mAh g −1 after 45 cycles, corresponding to 77.3% of the initial charge capacity. With increasing of Na content in Li 3-x Na x V 2 (PO 4 ) 3 , the as-obtained sample show poorer lithium storage capability than Li 3 V 2 (PO 4 ) 3 . As a result, Na 3 V 2 (PO 4 ) 3 shows the inferior cycling performance than other Li 3-x Na x V 2 (PO 4 ) 3 . It can only deliver a reversible capacity of 20.9 mAh g −1 after 45 cycles, corresponding to 45.9% of the initial charge capacity. In-situ X-ray diffraction observations demonstrate that the poor electrochemical property of Na 3 V 2 (PO 4 ) 3 anode is due to the irreversible structural evolution during charge-discharge process. Therefore, reducing the Na 3 V 2 (PO 4 ) 3 phase in as-obtained sample is a feasible route to improve the lithium storage capability of Li 3-x Na x V 2 (PO 4 ) 3 .

The 3-loop pure singlet heavy flavor contributions to the structure function F2(x,Q2 and the anomalous dimension

Directory of Open Access Journals (Sweden)

J. Ablinger

2015-01-01

Full Text Available The pure singlet asymptotic heavy flavor corrections to 3-loop order for the deep-inelastic scattering structure function F2(x,Q2 and the corresponding transition matrix element AQq(3,PS in the variable flavor number scheme are computed. In Mellin-N space these inclusive quantities depend on generalized harmonic sums. We also recalculate the complete 3-loop pure singlet anomalous dimension for the first time. Numerical results for the Wilson coefficients, the operator matrix element and the contribution to the structure function F2(x,Q2 are presented.

The 3-loop pure singlet heavy flavor contributions to the structure function F2(x,Q2) and the anomalous dimension

International Nuclear Information System (INIS)

Ablinger, J.; Behring, A.; Blümlein, J.; De Freitas, A.; Manteuffel, A. von; Schneider, C.

2015-01-01

The pure singlet asymptotic heavy flavor corrections to 3-loop order for the deep-inelastic scattering structure function F 2 (x,Q 2 ) and the corresponding transition matrix element A Qq (3),PS in the variable flavor number scheme are computed. In Mellin-N space these inclusive quantities depend on generalized harmonic sums. We also recalculate the complete 3-loop pure singlet anomalous dimension for the first time. Numerical results for the Wilson coefficients, the operator matrix element and the contribution to the structure function F 2 (x,Q 2 ) are presented

Implementación del Algoritmo Sünter-Clare en un Convertidor Matricial 3x3

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Eliher A. Ortiz Colín

2017-10-01

Full Text Available Resumen: En este trabajo se presenta la implementación digital del algoritmo de modulación de Sünter-Clare, para un convertidor matricial de tres hilos de 7.5 kVA. Este algoritmo es usado para calcular los ciclos de trabajo en un convertidor matricial 3x3, con lo que se generan tensiones de salida con amplitud y frecuencia constantes. El algoritmo de modulación de Sünter-Clare recalcula los tiempos y trayectorias de conmutación cada período de muestreo, con el objetivo de compensar las variaciones de amplitud y de frecuencia de las tensiones de entrada. Este algoritmo se ejecuta en cada muestreo y está en función de la tensión trifásica de entrada y de la tensión de referencia de salida, resultando adecuado para controles en lazo cerrado, cuando las señales de amplitud y de frecuencia de las tensiones de entrada son variables en el tiempo, como ocurre en los sistemas de generación de energía eléctrica a velocidad variable, que utilizan la energía del viento como fuente primaria de energía. El sistema de control para el trabajo experimental, además de la tarjeta del convertidor matricial, está compuesto por una tarjeta de arreglos de compuertas programable (FPGA y por un procesador digital de señales (DSP con una tarjeta de interfaz gráfica. Abstract: This paper presents the direct and easy way to implement digitally a Sünter-Clare modulation algorithm for a 7.5 KVA, three-wires, matrix converter. This modulation algorithm is used to calculate 3x3 matrix converter duty cycles to produce constant output voltage and frequency signals. The Sünter-Clare modulation algorithm recalculates switching patterns and switching times every sampling period in order to compensate the input voltage and frequency variations. This algorithm is defined in terms of the three-phase input and the output reference voltages at each sampling instant and is convenient for closed loop operations when the input voltage and frequency are variable in

Kaon matrix elements and CP violation from quenched lattice QCD: The 3-flavor case

International Nuclear Information System (INIS)

Blum, T.; Wingate, M.; Chen, P.; Christ, N.; Cristian, C.; Fleming, G.; Mawhinney, R.; Siegert, G.; Wu, L.; Zhestkov, Y.; Dawson, C.; Soni, A.; Ohta, S.; Vranas, P.

2003-01-01

We report the results of a calculation of the K→ππ matrix elements relevant for the ΔI=1/2 rule and ε ' /ε in quenched lattice QCD using domain wall fermions at a fixed lattice spacing a -1 ∼2 GeV. Working in the three-quark effective theory, where only the u, d, and s quarks enter and which is known perturbatively to next-to-leading order, we calculate the lattice K→π and K→|0> matrix elements of dimension six, four-fermion operators. Through lowest order chiral perturbation theory these yield K→ππ matrix elements, which we then normalize to continuum values through a nonperturbative renormalization technique. For the ratio of isospin amplitudes vertical bar A 0 vertical bar/vertical bar A 2 vertical bar we find a value of 25.3±1.8 (statistical error only) compared to the experimental value of 22.2, with individual isospin amplitudes 10%-20% below the experimental values. For ε ' /ε, using known central values for standard model parameters, we calculate (-4.0±2.3)x10 -4 (statistical error only) compared to the current experimental average of (17.2±1.8)x10 -4 . Because we find a large cancellation between the I=0 and I=2 contributions to ε ' /ε, the result may be very sensitive to the approximations employed. Among these are the use of quenched QCD, lowest order chiral perturbation theory, and continuum perturbation theory below 1.3 GeV. We also calculate the kaon B parameter B K and find B K,MS (2 GeV)=0.532(11). Although currently unable to give a reliable systematic error, we have control over statistical errors and more simulations will yield information about the effects of the approximations on this first-principles determination of these important quantities

Plastic deformation of YBa2Cu3O7-x superconductor compound

International Nuclear Information System (INIS)

Torres V, G.; Moreno, J.E.

1988-01-01

The high temperature superconductor YBa 2 Cu 3 O 7-x shown a brittle behavior when deformed under ambient conditions. If a hydrostatic state of stress is imposed with a metal matrix, it is possible to induce exttended plastic deformations as a great as 200% were achieved using this method without loosing the superconductivity in the ceramic. The observed deformations mechanisms are similar to those observed in the superplastic metals and the boundary ceramic metal matrix was found to be highly coherent. This method opens a new technique that can be apllied in the manufacture of superconductor wire. (author) [pt

Electrical transport of (1-x)La0.7Ca0.3MnO3+xAl2O3 composites

International Nuclear Information System (INIS)

Phong, P.T.; Khiem, N.V.; Dai, N.V.; Manh, D.H.; Hong, L.V.; Phuc, N.X.

2009-01-01

We report the resistivity (ρ)-temperature (T) patterns in (1-x)La 0,7 Ca 0,3 MnO 3 +xAl 2 O 3 composites (0≤x≤0.05) over a temperature regime of 50-300 K. Al 2 O 3 addition has increased the resistivity of these composites. The Curie temperature (T C ) is almost independent on the Al 2 O 3 content and is about 250 K for all the samples, while the metal-insulator transition temperature (T MI ) decreases with increasing Al 2 O 3 content. Based on the phenomenological equation for conductivity under a percolation approach, which is dependent on the phase segregation of ferromagnetic metallic clusters and paramagnetic insulating regions, we fitted the experimental data (ρ-T) from 50 to 300 K and find that the activation barrier increases as Al 2 O 3 content increases.

Synthesis and magnetic properties of layered MnPSxSe3-x (0 < x < 3) and corresponding intercalation compounds of 2,2'-bipyridine

International Nuclear Information System (INIS)

Yan, Xiaobing; Chen, Xingguo; Qin, Jingui

2011-01-01

Graphical abstract: A series of new layered MnPS x Se 3-x (0 x Se 3-x exhibited antiferromagnetism similar to MnPS 3 or MnPSe 3 , but the intercalation of 2,2'-bipyridine can dramatically change the properties of MnPS x Se 3-x slab. Research highlights: → A series of new MnPS x Se 3-x are designed and synthesized for the first time and their layered structure has been determined. → The intercalation chemistry has been initially studied via the intercalation of 2,2'-bipyridine with MnPS x Se 3-x . → The magnetic properties of the series MnPS x Se 3-x and the corresponding intercalation compounds of 2,2'-bipydine have been studied. And the relationship between the structure and the magnetic propertied has been primarily explored. -- Abstract: In this work, we synthesize a series of new MnPS x Se 3-x (0 1-y PS x Se 3-x (bipy) 4y , x = 1.2, 1.8 and 2.4) via the intercalation of 2,2'-bipyridine with MnPS x Se 3-x . XRD results confirm that MnPS x Se 3-x compounds show the layered structure and can be regarded as the solid solution of MnPS 3 and MnPSe 3 . Magnetic measurements indicate that MnPS x Se 3-x compounds exhibit paramagnetism with negative Weiss constant in the paramagnetic temperature region, and an antiferromagnetic phase transition occurs at the Neel temperature. It is found that the magnetic properties of MnPS x Se 3-x slab are dramatically changed after the intercalation of 2,2'-bipyridine, which is close related to the relative ratio of S and Se atom as well as the intralayered Mn 2+ vacancies of MnPS x Se 3-x slab.

Photoluminescent properties of LiSrxBa1-xPO4:RE3+ (RE = Sm3+, Eu3+) f-f transition phosphors

International Nuclear Information System (INIS)

Tu Dong; Liang Yujun; Liu Rong; Cheng Zheng; Yang Fan; Yang Wenlong

2011-01-01

Highlights: → Novel phosphors LiSr x Ba 1-x PO 4 : Sm 3+ and LiSr x Ba 1-x PO 4 : Eu 3+ have been synthesized by solid-state reaction method. → The LiSr x Ba 1-x PO 4 : Sm 3+ and LiSr x Ba 1-x PO 4 : Eu 3+ phosphors may be potential f-f transition phosphors used in LED. → The emission intensity of the LiSr x Ba 1-x PO 4 : Sm 3+ and LiSr x Ba 1-x PO 4 : Eu 3+ phosphors can be enhanced by increasing the value of x. - Abstract: Rare-earth ions (Sm 3+ or Eu 3+ ) doped LiSr x Ba 1-x PO 4 (x = 0, 0.2, 0.4, 0.6, 0.8, 1.0) f-f transition phosphor powders were prepared by a high temperature solid-state reaction. The resulted phosphors were characterized by X-ray diffraction (XRD) and photoluminescence (PL) spectroscopy. The results of XRD indicate that the phase structure of the sample changes from LiBaPO 4 to LiSrPO 4 when x changes from 0 to 1.0. The excitation spectra indicate that only direct excitation of rare earth ions (Sm 3+ or Eu 3+ ) can be observed. The doped rare earth ions show their characteristic emission in LiSr x Ba 1-x PO 4 , i.e., Eu 3+5 D 0 - 7 F J (J = 0, 1, 2, 3, 4), Sm 3+4 G 5/2 → 6 H J (J = 5/2, 7/2, 9/2, 11/2), respectively. The dependence of the emission intensities of the LiSr x Ba 1-x PO 4 :Sm 3+ and LiSr x Ba 1-x PO 4 :Eu 3+ phosphors on the x value and Ln 3+ (Ln 3+ = Sm 3+ , Eu 3+ ) concentration is also investigated.

New sparse matrix solver in the KIKO3D 3-dimensional reactor dynamics code

International Nuclear Information System (INIS)

Panka, I.; Kereszturi, A.; Hegedus, C.

2005-01-01

The goal of this paper is to present a more effective method Bi-CGSTAB for accelerating the large sparse matrix equation solution in the KIKO3D code. This equation system is obtained by using the factorization of the improved quasi static (IQS) method for the time dependent nodal kinetic equations. In the old methodology standard large sparse matrix techniques were considered, where Gauss-Seidel preconditioning and a GMRES-type solver were applied. The validation of KIKO3D using Bi-CGSTAB has been performed by solving of a VVER-1000 kinetic benchmark problem. Additionally, the convergence characteristics were investigated in given macro time steps of Control Rod Ejection transients. The results have been obtained by the old GMRES and new Bi-CGSTAB methods are compared. (author)

Structural and electrical properties of (1-x)(Na1/2Bi1/2)TiO3-xPb(Mg1/3Nb2/3)O3 solid solution

International Nuclear Information System (INIS)

Lee, J.-K.; Yi, J.Y.; Hong, K.S.

2004-01-01

Structural, dielectric and piezoelectric properties of (1-x)(Na 1/2 Bi 1/2 )TiO 3 -xPb(Mg 1/3 Nb 2/3 )O 3 (NBT-xPMN) solid solution have been investigated. An addition of PMN into NBT transformed the structure of sintered samples from rhombohedral to pseudocubic phase where x is larger than 0.1. In calcined powders, however, the intermediate structure were observed between rhombohedral and cubic phases near x=0.1. The formation of solid solution between NBT and PMN modified the dielectric and piezoelectric properties of NBT to be suitable for high temperature dielectric and piezoelectric material. With increasing the content of PMN, the temperature-stability of ε r (T) increased and the high temperature dielectric loss decreased. In addition, the piezoelectric property of NBT-xPMN was enhanced, for the decrease of coercive field and conductivity promoted the domain reversal under the high electric field of the poling process

POWER, HEART RATE AND PERCEIVED EXERTION RESPONSES TO 3X3 AND 4X4 BASKETBALL SMALL-SIDED GAMES

Directory of Open Access Journals (Sweden)

Jaime Sampaio

2009-01-01

significant increase in the countermovement jump posttest jump results could suggest that the 4x4 were not played as quickly nor intensely as the 3x3. Decreases of the space and number of players in game allow greater self-recreation of players and greater intervention in game. Therefore, the heart rate response during the series displays a higher physiologic impact in 3x3 than in 4x4.

Cation mobility in NASICON compounds Li1-xZr2-xNbx(PO4)3 and Li1+xZr2-xScx(PO4)3

International Nuclear Information System (INIS)

Stenina, I.A.; Yaroslavtsev, A.B.; Aliev, A.D.; Antipov, E.V.; Velikodnyj, Yu.A.; Rebrov, A.I.

2002-01-01

Compounds featuring NASICON structure of the composition Li 1-x Zr 2-x Nb x (PO 4 ) 3 and Li 1+x Zr 2-x Sc x (PO 4 ) 3 were studied by the method of X-ray phase analysis and 7 Li and 31 P NMR. Structure of Li 0.8 Zr 1.8 Nb 0.2 (PO 4 ) 3 was refined on the basis of X-ray powder pattern. It is shown that cationic disordering in LiZr 2 (PO 4 ) 3 is stimulated both by cationic vacancies and interstitial atoms formation. The cationic vacancies are characterized by a higher mobility. The level of intrinsic disordering was estimated and the Frenkel constant for the compound was calculated [ru

Mn-substituted perovskites RECoxMn1-xO3: a comparison between magnetic properties of LaCoxMn1-xO3 and GdCoxMn1-xO3

Directory of Open Access Journals (Sweden)

Barahona, P.

2008-08-01

Full Text Available Cooperative phenomena constitute important mechanisms to explain the magnetic properties of the perovskite manganites REMnO3, in which the rare-earth and/or Mn is partially replaced by divalent elements. In this way, the manganese ion changes its valence state (Mn3+ Mn4+, triggering strong magnetic interactions. In this work we describe the case of GdCoxMn1-xO3 (0.0 ≤ x ≤ 1.0 for which the antiferromagnetic interaction between the Gd sublattice and the Mn/Co network leads to a reversal of the magnetic moment at low temperature. No inversion is observed for the LaCoxMn1-xO3 series, in which the ordering temperature may attain a maximum of 235 K for LaCo0.50Mn0.50O3, while it is only 120 K for similar Co/Mn ratio in the case of GdCo0.50Mn0.50O3. Magnetic properties are described in terms of two regimes: one, for x 3 manganite and another one, for x > 0.5, when Mn substitutes Co in the GdCoO3 cobaltite, while the magnetic interactions are maximized at x(Co = 0.50. This hypothesis is discussed in terms of the respective oxidation states of both manganese (Mn3+ / Mn4+ and cobalt (Co2+ / Co3+.El fenómeno cooperativo constituye un importante mecanismo para explicar las propiedades magnéticas de las perovskitas manganitas TRMnO3, en las que el catión de tierra rara, TR, y/o el catión Mn3+ son parcialmente reemplazados por cationes divalentes. Por esta vía el ión de manganeso cambia de estado de valencia (Mn3+ Mn4+, generando fuertes interacciones magnéticas. En el presente trabajo se describe el caso de las soluciones sólidas GdCoxMn1-xO3 (0.0 ≤ x ≤ 1.0 para las que la interacción antiferromagnética entre la subred del Gd3+ y la red Mn/Co lleva a una inversión del momento magnético a baja temperatura. No se ha observado inversión para la serie LaCoxMn1-xO3, en que la temperatura de orden puede alcanzar un máximo de 235K para LaCo0.50Mn0.50O3, mientras que en el caso de GdCo0.50Mn0.50O3, en que sí se observa inversión, la

Crystal Structure Formation of CH3NH3PbI3-xClx Perovskite

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Shiqiang Luo

2016-02-01

Full Text Available Inorganic-organic hydride perovskites bring the hope for fabricating low-cost and large-scale solar cells. At the beginning of the research, two open questions were raised: the hysteresis effect and the role of chloride. The presence of chloride significantly improves the crystallization and charge transfer property of the perovskite. However, though the long held debate over of the existence of chloride in the perovskite seems to have now come to a conclusion, no prior work has been carried out focusing on the role of chloride on the electronic performance and the crystallization of the perovskite. Furthermore, current reports on the crystal structure of the perovskite are rather confusing. This article analyzes the role of chloride in CH3NH3PbI3-xClx on the crystal orientation and provides a new explanation about the (110-oriented growth of CH3NH3PbI3 and CH3NH3PbI3-xClx.

Binding of matrix metalloproteinase inhibitors to extracellular matrix: 3D-QSAR analysis.

Science.gov (United States)

Zhang, Yufen; Lukacova, Viera; Bartus, Vladimir; Nie, Xiaoping; Sun, Guorong; Manivannan, Ethirajan; Ghorpade, Sandeep R; Jin, Xiaomin; Manyem, Shankar; Sibi, Mukund P; Cook, Gregory R; Balaz, Stefan

2008-10-01

Binding to the extracellular matrix, one of the most abundant human protein complexes, significantly affects drug disposition. Specifically, the interactions with extracellular matrix determine the free concentrations of small molecules acting in tissues, including signaling peptides, inhibitors of tissue remodeling enzymes such as matrix metalloproteinases, and other drug candidates. The nature of extracellular matrix binding was elucidated for 63 matrix metalloproteinase inhibitors, for which the association constants to an extracellular matrix mimic were reported here. The data did not correlate with lipophilicity as a common determinant of structure-nonspecific, orientation-averaged binding. A hypothetical structure of the binding site of the solidified extracellular matrix surrogate was analyzed using the Comparative Molecular Field Analysis, which needed to be applied in our multi-mode variant. This fact indicates that the compounds bind to extracellular matrix in multiple modes, which cannot be considered as completely orientation-averaged and exhibit structural dependence. The novel comparative molecular field analysis models, exhibiting satisfactory descriptive and predictive abilities, are suitable for prediction of the extracellular matrix binding for the untested chemicals, which are within applicability domains. The results contribute to a better prediction of the pharmacokinetic parameters such as the distribution volume and the tissue-blood partition coefficients, in addition to a more imminent benefit for the development of more effective matrix metalloproteinase inhibitors.

The 3-loop non-singlet heavy flavor contributions and anomalous dimensions for the structure function F2(x,Q2 and transversity

Directory of Open Access Journals (Sweden)

J. Ablinger

2014-09-01

Full Text Available We calculate the massive flavor non-singlet Wilson coefficient for the heavy flavor contributions to the structure function F2(x,Q2 in the asymptotic region Q2≫m2 and the associated operator matrix element Aqq,Q(3,NS(N to 3-loop order in Quantum Chromodynamics at general values of the Mellin variable N. This matrix element is associated with the vector current and axial vector current for the even and the odd moments N, respectively. We also calculate the corresponding operator matrix elements for transversity, compute the contributions to the 3-loop anomalous dimensions to O(NF and compare to results in the literature. The 3-loop matching of the flavor non-singlet distribution in the variable flavor number scheme is derived. All results can be expressed in terms of nested harmonic sums in N space and harmonic polylogarithms in x-space. Numerical results are presented for the non-singlet charm quark contribution to F2(x,Q2.

The 3-loop non-singlet heavy flavor contributions and anomalous dimensions for the structure function F2(x,Q2) and transversity

International Nuclear Information System (INIS)

Ablinger, J.; Hasselhuhn, A.; Schneider, C.; Manteuffel, A. von

2014-06-01

We calculate the massive flavor non-singlet Wilson coefficient for the heavy flavor contributions to the structure function F 2 (x,Q 2 ) in the asymptotic region Q 2 >>m 2 and the associated operator matrix element A (3),NS qq,Q (N) to 3-loop order in Quantum Chromodynamics at general values of the Mellin variable N. This matrix element is associated to the vector current and axial vector current for the even and the odd moments N, respectively. We also calculate the corresponding operator matrix elements for transversity, compute the contributions to the 3-loop anomalous dimensions to O(N F ) and compare to results in the literature. The 3-loop matching of the flavor non-singlet distribution in the variable flavor number scheme is derived. All results can be expressed in terms of nested harmonic sums in N space and harmonic polylogarithms in x-space. Numerical results are presented for the non-singlet charm quark contribution to F 2 (x,Q 2 ).

The 3-loop non-singlet heavy flavor contributions and anomalous dimensions for the structure function F2(x,Q2) and transversity

International Nuclear Information System (INIS)

Ablinger, J.; Behring, A.; Blümlein, J.; De Freitas, A.; Hasselhuhn, A.; Manteuffel, A. von; Round, M.; Schneider, C.; Wißbrock, F.

2014-01-01

We calculate the massive flavor non-singlet Wilson coefficient for the heavy flavor contributions to the structure function F 2 (x,Q 2 ) in the asymptotic region Q 2 ≫m 2 and the associated operator matrix element A qq,Q (3),NS (N) to 3-loop order in Quantum Chromodynamics at general values of the Mellin variable N. This matrix element is associated with the vector current and axial vector current for the even and the odd moments N, respectively. We also calculate the corresponding operator matrix elements for transversity, compute the contributions to the 3-loop anomalous dimensions to O(N F ) and compare to results in the literature. The 3-loop matching of the flavor non-singlet distribution in the variable flavor number scheme is derived. All results can be expressed in terms of nested harmonic sums in N space and harmonic polylogarithms in x-space. Numerical results are presented for the non-singlet charm quark contribution to F 2 (x,Q 2 )

Enhanced corrosion resistance of A3xx.x/SiCp composites in chloride media by La surface treatments

International Nuclear Information System (INIS)

Pardo, A.; Merino, M.C.; Arrabal, R.; Feliu, S.; Viejo, F.; Carboneras, M.

2006-01-01

The influence of silicon carbide particles (SiCp) proportion and matrix composition of aluminium metal matrix composites (A3xx.x/SiCp) modified by lanthanum-based conversion or electrolysis coating was evaluated in 3.5 wt% NaCl aerated solution. The intermetallic compounds were preferentially covered by lanthanum-based conversion coatings obtained by immersion in 50 deg. C solution of La(III) salt, and the intermetallic compounds, SiCp and aluminium matrix were covered by lanthanum electrolysis treatment. The corrosion process was studied on the basis of gravimetric tests and electrochemical impedance spectroscopy (EIS) during immersion in 3.5 wt% NaCl aerated solution. The composition of both La coating and corrosion products was analyzed before and after accelerated testing, by scanning electron microscopy (SEM), atomic force microscopy (AFM), low-angle X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS) to determine the influence of surface microstructural changes on corrosion behaviour during exposure to the corrosive environment. The corrosion process was more influenced by the concentration of alloy elements in the matrix than by the proportion of SiCp reinforcement. Both lanthanum treated surfaces presented better behaviour to chloride solution corrosion than original composite surfaces without treatment; however, electrolysis afforded a higher degree of protection than the conversion treatment because the coating was more extensive

Structural Characteristics and Magnetic Properties of Al2O3 Matrix-Based Co-Cermet Nanogranular Films

Directory of Open Access Journals (Sweden)

Giap Van Cuong

2015-01-01

Full Text Available Magnetic micro- and nanogranular materials prepared by different methods have been used widely in studies of magnetooptical response. However, among them there seems to be nothing about magnetic nanogranular thin films prepared by a rf cosputtering technique for both metals and insulators till now. This paper presented and discussed preparation, structural characteristics, and magnetic properties of alumina (Al2O3 matrix-based granular Co-cermet thin films deposited by means of the cosputtering technique for both Co and Al2O3. By varying the ferromagnetic (Co atomic fraction, x, from 0.04 to 0.63, several dominant features of deposition for these thin films were shown. Structural characteristics by X-ray diffraction confirmed a cermet-type structure for these films. Furthermore, magnetic behaviours presented a transition from paramagnetic- to superparamagnetic- and then to ferromagnetic-like properties, indicating agglomeration and growth following Co components of Co clusters or nanoparticles. These results show a typical granular Co-cermet feature for the Co-Al2O3 thin films prepared, in which Co magnetic nanogranules are dispersed in a ceramic matrix. Such nanomaterials can be applied suitably for our investigations in future on the magnetooptical responses of spinplasmonics.

Magnetic interactions in HoCr{sub 1-x}Fe{sub x}O{sub 3} (x = 0, 0.2) investigated by neutron powder diffraction

Energy Technology Data Exchange (ETDEWEB)

Liu, Xinzhi, E-mail: liuxinzhi1984.cn@163.com [Department of Nuclear Physics, China Institute of Atomic Energy, Beijing 102413 (China); Hao, Lijie; Ma, Xiaobai [Department of Nuclear Physics, China Institute of Atomic Energy, Beijing 102413 (China); Wang, Chin-Wei [Neutron Group, National Synchrotron Radiation Research Center, Hsinchu 30077, Taiwan (China); Klose, Frank [Australian Nuclear Science and Technology Organization, Lucas Heights, New South Wales 2234 (Australia); Department of Physics and Materials Science, The City University of Hong Kong, Hong Kong Special Administrative Region (Hong Kong); Liu, Yuntao, E-mail: ytliu@ciae.ac.cn [Department of Nuclear Physics, China Institute of Atomic Energy, Beijing 102413 (China); Sun, Kai; Li, Yuqing [Department of Nuclear Physics, China Institute of Atomic Energy, Beijing 102413 (China); Chen, Dongfeng, E-mail: dongfeng@ciae.ac.cn [Department of Nuclear Physics, China Institute of Atomic Energy, Beijing 102413 (China)

2017-07-01

Highlights: • The temperature dependent magnetism of HoCr{sub 1-x}Fe{sub x}O{sub 3} (x = 0, 0.2) were investigated by neutron diffraction. • Cr{sup 3+} moment follows a mean field theory while Ho{sup 3+} follows a spin 1/2 model. • An magneto-elastic strain was observed accompanying with the ordering of Cr{sup 3+}. - Abstract: The temperature dependent magnetism of Fe-doped rare earth orthochromite HoCr{sub 1-x}Fe{sub x}O{sub 3}(x = 0, 0.2) was investigated by neutron powder diffraction. It is found that the magnetism of Cr(Fe){sup 3+} can be well understood within mean field theory, while the ordering of Ho{sup 3+} was induced by the Cr(Fe){sup 3+} sublattice and can be satisfyingly described by an effective S = 1/2 model. The absences of both the most common G{sub x}F{sub z} configuration of Cr{sup 3+} and the ordering of Ho{sup 3+} caused by Ho-Ho interaction evidence a strong Ho{sup 3+}-Cr{sup 3+} interaction which dominates this system. On the other hand, a remarkable magnetoelastic strain was observed accompanying the Cr(Fe){sup 3+} ordering. An analysis based on the equation of state with a Grüneisen approximation was performed and revealed magnetic origin of this strain.

CYGNUS X-3: ITS LITTLE FRIEND’S COUNTERPART, THE DISTANCE TO CYGNUS X-3, AND OUTFLOWS/JETS

Energy Technology Data Exchange (ETDEWEB)

McCollough, M. L.; Dunham, M. M. [Smithsonian Astrophysical Observatory, 60 Garden Street, Cambridge, MA 02138 (United States); Corrales, L., E-mail: mmccollough@cfa.harvard.edu [Kavli Institute for Astrophysics and Space Research, Massachusetts Institute of Technology, Cambridge, MA 02139 (United States)

2016-10-20

Chandra observations have revealed a feature within 16″ of Cygnus X-3 that varied in phase with Cygnus X-3. This feature was shown to be a Bok globule that is along the line of sight to Cygnus X-3. We report on observations made with the Submillimeter Array to search for molecular emission from this globule, also known as Cygnus X-3's “Little Friend.” We have found a counterpart in both {sup 12}CO (2-1) and {sup 13}CO (2-1) emission. From the velocity shift of the molecular lines we are able to find two probable distances based on the Bayesian model of Milky Way kinematics of Reid et al. For the LF velocity of −47.5 km s{sup −1}, we find distances of 6.1 ± 0.6 kpc (62% probability) and 7.8 ± 0.6 kpc (38% probability). This yields distances to Cyg X-3 of 7.4 ± 1.1 kpc and 10.2 ± 1.2 kpc, respectively. Based on the probabilities entailed, we take 7.4 ± 1.1 kpc as the preferred distance to Cyg X-3. We also report the discovery of bipolar molecular outflow, suggesting that there is active star formation occurring within the Little Friend.

LiNbO3 :Pr3+ : A Multipiezo Material with Simultaneous Piezoelectricity and Sensitive Piezoluminescence.

Science.gov (United States)

Tu, Dong; Xu, Chao-Nan; Yoshida, Akihito; Fujihala, Masayoshi; Hirotsu, Jou; Zheng, Xu-Guang

2017-06-01

Red-emitting piezoluminescence (elasticoluminescence) is achieved by doping rare earth Pr 3+ into the well-known piezoelectric matrix, LiNbO 3 . By precisely tuning the Li/Nb ratio in nonstoichiometric Li x NbO 3 :Pr 3+ , a material that exhibits an unusually high piezoluminescence intensity, which far exceeds that of any well-known piezoelectric material, is produced. Li x NbO 3 :Pr 3+ shows excellent strain sensitivity at the lowest strain level, with no threshold for stress sensing. These multipiezo properties of sensitive piezoluminescence in a piezoelectric matrix are ideal for microstress sensing, damage diagnosis, electro-mechano-optical energy conversion, and multifunctional control in optoelectronics. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

A study on magnetoelastic properties of Tb3 (Fe28-xCox) V1.0 (x=0, 3, 6) compounds

International Nuclear Information System (INIS)

Gholizadeh, A.; Tajabor, N.; Pourarian, F.

2012-01-01

In this work, The magnetoelastic properties of polycrystalline samples of Tb 3 (Fe 28-x Co x ) V 1.0 (x=0, 3, 6) intermetallic compounds are investigated by means of linear thermal expansion and magnetostriction measurements in the temperature range of 77-515 K under applied magnetic fields up to 1.5 T. The linear thermal expansion increases with the Co content. The well-defined anomalies observed in the linear thermal expansion coefficients for Tb 3 (Fe 28-x Co x ) V 1.0 (x=0, 3, 6) compounds are associated with the magnetic ordering temperature for x=0 and spin reorientation temperatures for x=3, 6. Below transition temperatures, the value of the longitudinal magnetostriction (λ Pa ) at 1.6 T increases with Co content.

Synthesis and electrochemical properties of Ti4+ doped Li3-xFe2-xTix(PO4)3/C cathode materials

International Nuclear Information System (INIS)

Liu Zhanqiang; Huang Fuqiang; Sun Junkang

2011-01-01

Highlights: → Li 3-x Fe 2-x Ti x (PO 4 ) 3 /C composite cathodes were prepared by ball-milling method. Ti-doping can improve the electrochemical property of Li 3 Fe 2 (PO 4 ) 3 . → The optimized doping level was found to be x = 0.2. → The second phase of LiTi 2 (PO 4 ) 3 will emerge if the doping level higher than 0.2. - Abstract: Li 3-x Fe 2-x Ti x (PO 4 ) 3 /C (x = 0-0.4) cathodes designed with Fe doped by Ti was studied. Both Li 3 Fe 2 (PO 4 ) 3 /C (x = 0) and Li 2.8 Fe 1.8 Ti 0.2 (PO 4 ) 3 /C (x = 0.2) possess two plateau potentials of Fe 3+ /Fe 2+ couple (around 2.8 V and 2.7 V vs. Li + /Li) upon discharge observed from galvanostatic charge/discharge and cyclic voltammetry. Li 2.8 Fe 1.8 Ti 0.2 (PO 4 ) 3 /C has higher reversibility and better capacity retention than that of the undoped Li 3 Fe 2 (PO 4 ) 3 /C. A much higher specific capacity of 122.3 mAh/g was obtained at C/20 in the first cycle, approaching the theoretical capacity of 128 mAh/g, and a capacity of 100.1 mAh/g was held at C/2 after the 20th cycle.

Theoretical study on guided wave propagation in (1 - x)Pb(Mg1/3Nb2/3)O3-xPbTiO3 (x = 0.29 and 0.33) single crystal plates

International Nuclear Information System (INIS)

Chen Chuanwen; Zhang Rui; Cao Wenwu

2009-01-01

The propagation of guided waves in free standing (1 - x)Pb(Mg 1/3 Nb 2/3 )O 3 -xPbTiO 3 [PMN-xPT] (x = 0.29 or 0.33) single crystal plates has been studied theoretically. The polar directions are in the (111) family directions of the cubic reference coordinates but the crystals are being polarized along [0 0 1] c , [0 1 1] c and [1 1 1] c of the cubic reference directions so that the effective microscopic symmetries are 4mm, mm2 and 3m, respectively. Multiple mode couplings appear in the dispersion curves for both the symmetric and the antisymmetric Lamb and shear horizontal modes. The velocities of most guided waves decrease rapidly with frequency. Then, after passing a minimum, they begin to increase with frequency and eventually saturate to the shear wave velocity v sz (or v 1 = 3507 m s -1 for [1 1 1] c polarized sample). For a [1 1 1] c polarized single domain PMN-0.33PT sample, the S 1 mode instead of the S 0 mode approaches the Rayleigh velocity v R at high frequencies.

Microstructure and properties of hot extruded Mg-3Zn-Y-xCu (x = 0, 1, 3, 5) alloys

Energy Technology Data Exchange (ETDEWEB)

Liu, Bao-sheng; Kuang, Ya-fei; Fang, Da-qing; Chai, Yue-sheng [Taiyuan Univ. of Science and Technology (China). College of Materials Science and Engineering; Taiyuan Univ. of Science and Technology (China). Engineering Research Center for Magnesium Alloys of Shanxi Province; Zhang, Yue-zhong [Taiyuan Univ. of Science and Technology (China). Engineering Research Center for Magnesium Alloys of Shanxi Province; Taiyuan Univ. of Science and Technology (China). College of Chemical and Biological Engineering

2017-04-15

In petroleum drilling engineering, materials with high strength and rapid degradation are required for degradable fracturing ball applications. In this work, the microstructure, mechanical properties, and corrosion behavior of extruded Mg-3Zn-Y-xCu (x = 0, 1, 3, 5 weight percent) alloys are investigated using optical microscopy, scanning electronic microscopy equipped with energy dispersive X-ray spectroscopy, X-ray diffraction, transmission electronic microscopy, compression tests, electrochemical measurements, and hydrogen evolution tests, to explore their potential as excellent candidate alloys for degradable fracturing ball applications. It is found that the Mg-3Zn-Y alloy is mainly composed of α-Mg, Mg{sub 3}Zn{sub 3}Y{sub 2}, and Mg{sub 3}Zn{sub 6}Y phases. After Cu addition, a new MgZnCu phase is formed, while the Mg{sub 3}Zn{sub 3}Y{sub 2} phase disappears. The Mg-3Zn-Y-3Cu alloy shows the highest compressive strength (473 MPa) and yield strength (402 MPa), mainly attributed to the combined effect of the fine-grain and dispersed precipitation of Mg{sub 3}Zn{sub 6}Y and MgZnCu. The corrosion rate of Mg-3Zn-Y-3Cu reaches 0.41 mm day{sup -1} in 3.5 wt.% KCl solution. Consequently, Mg-3Zn-Y-3Cu alloy is a suitable degradable fracturing ball-seat material.

The O(αs3TF2) contributions to the gluonic operator matrix element

International Nuclear Information System (INIS)

Ablinger, J.; Blümlein, J.; De Freitas, A.; Hasselhuhn, A.; Manteuffel, A. von; Round, M.; Schneider, C.

2014-01-01

The O(α s 3 T F 2 C F (C A )) contributions to the transition matrix element A gg,Q relevant for the variable flavor number scheme at 3-loop order are calculated. The corresponding graphs contain two massive fermion lines of equal mass leading to terms given by inverse binomially weighted sums beyond the usual harmonic sums. In x-space two root-valued letters contribute in the iterated integrals in addition to those forming the harmonic polylogarithms. We outline technical details needed in the calculation of graphs of this type, which are as well of importance in the case of two different internal massive lines

Solid-state interaction between nickel and YBa/sub 2/Cu/sub 3/O/sub x/

Energy Technology Data Exchange (ETDEWEB)

Champagne, B; Parent, L; Moreau, C

1989-01-01

As part of a search for suitable metals for use in composite cables made up of high-temperature superconductors in a metallic matrix, the solid-state reaction between nickel and YBa/sub 2/Cu/sub 3/O/sub x/ was studied. Green compacts of YBa/sub 2/Cu/sub 3/O/sub x/ were hot isostatically pressed (HIPed) in nickel. The microstructure, density and nature of phases present in HIPed parts were characterized. Resistivity measurements indicated that HIPed parts are not superconducting owing to the loss of oxygen and required an annealing step in oxygen for restoring superconductivity. The diffusion of nickel into YBa/sub 2/Cu/sub 3/O/sub x/ as well as the diffusion of Ba, Cu and Y into nickel was very limited. However, a thin interaction zone consisting of a nickel-rich oxide compound was formed at the Ni-YBa/sub 2/Cu/sub 3/O/sub x/ interface. The presence of such an interaction zone could have a detrimental effect on the thermal stabilization of Ni-YBa/sub 2/Cu/sub 3/O/sub x/ composite wires. 7 refs., 6 figs., 1 tab.

Stable Chloro- and Bromoxenate Cage Anions; [X3(XeO3)3]3- and [X4(XeO3)4]4- (X = Cl or Br).

Science.gov (United States)

Goettel, James T; Haensch, Veit G; Schrobilgen, Gary J

2017-06-28

The number of isolable compounds which contain different noble-gas-element bonds is limited for xenon and even more so for krypton. Examples of Xe-Cl bonds are rare, and prior to this work, no Xe-Br bonded compound had been isolated in macroscopic quantities. The syntheses, isolation, and characterization of the first compounds to contain Xe-Br bonds and their chlorine analogues are described in the present work. The reactions of XeO 3 with [N(CH 3 ) 4 ]Br and [N(C 2 H 5 ) 4 ]Br have provided two bromoxenate salts, [N(C 2 H 5 ) 4 ] 3 [Br 3 (XeO 3 ) 3 ] and [N(CH 3 ) 4 ] 4 [Br 4 (XeO 3 ) 4 ], in which the cage anions have Xe-Br bond lengths that range from 3.0838(3) to 3.3181(8) Å. The isostructural chloroxenate anions (Xe-Cl bond lengths, 2.9316(2) to 3.101(4) Å) were synthesized by analogy with their bromine analogues. The bromo- and chloroxenate salts are stable in the atmosphere at room temperature and were characterized in the solid state by Raman spectroscopy and low-temperature single-crystal X-ray diffraction, and in the gas phase by quantum-chemical calculations. They are the only known examples of cage anions that contain a noble-gas element. The Xe-Br and Xe-Cl bonds are very weakly covalent and can be viewed as σ-hole interactions, similar to those encountered in halogen bonding. However, the halogen atoms in these cases are valence electron lone pair donors, and the σ* Xe-O orbitals are lone pair acceptors.

N=2 Minimal Conformal Field Theories and Matrix Bifactorisations of x d

Science.gov (United States)

Davydov, Alexei; Camacho, Ana Ros; Runkel, Ingo

2018-01-01

We establish an action of the representations of N = 2-superconformal symmetry on the category of matrix factorisations of the potentials x d and x d - y d , for d odd. More precisely we prove a tensor equivalence between (a) the category of Neveu-Schwarz-type representations of the N = 2 minimal super vertex operator algebra at central charge 3-6/d, and (b) a full subcategory of graded matrix factorisations of the potential x d - y d . The subcategory in (b) is given by permutation-type matrix factorisations with consecutive index sets. The physical motivation for this result is the Landau-Ginzburg/conformal field theory correspondence, where it amounts to the equivalence of a subset of defects on both sides of the correspondence. Our work builds on results by Brunner and Roggenkamp [BR], where an isomorphism of fusion rules was established.

An ab initio study on MgX3- and CaX3- superhalogen anions (X=F, Cl, Br)

International Nuclear Information System (INIS)

Anusiewicz, Iwona; Sobczyk, Monika; Dabkowska, Iwona; Skurski, Piotr

2003-01-01

The vertical electron detachment energies (VDEs) of twenty MX 3 - (M=Mg, Ca; X=F, Cl, Br) anions were calculated at the OVGF level with the 6-311++G(3df) basis sets. The largest vertical electron binding energy was found for MgF 3 - system (8.793 eV). All negatively charged species possess the VDEs that are larger than 5.9 eV and thus may be termed superhalogen anions. The strong dependence of the VDE of the MX 3 - species on the ligand-central atom (M-X) distance and on the partial atomic charge localized on Mg or Ca was observed and discussed, as well as the other factors that may influence the electronic stability of such anions

An ab initio study on MgX 3- and CaX 3- superhalogen anions (X=F, Cl, Br)

Science.gov (United States)

Anusiewicz, Iwona; Sobczyk, Monika; Dąbkowska, Iwona; Skurski, Piotr

2003-06-01

The vertical electron detachment energies (VDEs) of twenty MX 3- (M=Mg, Ca; X=F, Cl, Br) anions were calculated at the OVGF level with the 6-311++G(3df) basis sets. The largest vertical electron binding energy was found for MgF 3- system (8.793 eV). All negatively charged species possess the VDEs that are larger than 5.9 eV and thus may be termed superhalogen anions. The strong dependence of the VDE of the MX 3- species on the ligand-central atom (M-X) distance and on the partial atomic charge localized on Mg or Ca was observed and discussed, as well as the other factors that may influence the electronic stability of such anions.

General working principles of CH3NH3PbX3 perovskite solar cells.

Science.gov (United States)

Gonzalez-Pedro, Victoria; Juarez-Perez, Emilio J; Arsyad, Waode-Sukmawati; Barea, Eva M; Fabregat-Santiago, Francisco; Mora-Sero, Ivan; Bisquert, Juan

2014-02-12

Organometal halide perovskite-based solar cells have recently realized large conversion efficiency over 15% showing great promise for a new large scale cost-competitive photovoltaic technology. Using impedance spectroscopy measurements we are able to separate the physical parameters of carrier transport and recombination in working devices of the two principal morphologies and compositions of perovskite solar cells, viz. compact thin films of CH3NH3PbI(3-x)Clx and CH3NH3PbI3 infiltrated on nanostructured TiO2. The results show nearly identical spectral characteristics indicating a unique photovoltaic operating mechanism that provides long diffusion lengths (1 μm). Carrier conductivity in both devices is closely matched, so that the most significant differences in performance are attributed to recombination rates. These results highlight the central role of the CH3NH3PbX3 semiconductor absorber in carrier collection and provide a new tool for improved optimization of perovskite solar cells. We report for the first time a measurement of the diffusion length in a nanostructured perovskite solar cell.

Microwave combustion synthesis of in situ Al{sub 2}O{sub 3} and Al{sub 3}Zr reinforced aluminum matrix composites

Energy Technology Data Exchange (ETDEWEB)

Zhu, Heguo, E-mail: zhg1200@sina.com [College of Materials Science and Engineering, Nanjing University of Science and Technology, Nanjing 210094 (China); Key Laboratory of Advanced Micro-Nano Materials and Technology, Jiangsu Province Higher Education Institutions, 210094 (China); Synergetic Center for Advanced Materials Research, Jiangsu Province Higher Education Institutions, 210094 (China); Hua, Bo; Cui, Tao; Huang, Jiewen; Li, Jianliang [College of Materials Science and Engineering, Nanjing University of Science and Technology, Nanjing 210094 (China); Xie, Zonghan, E-mail: zonghan.xie@adelaide.edu.au [School of Mechanical & Electrical Engineering, Wuhan Institute of Technology, Wuhan 430073 (China); School of Mechanical Engineering, University of Adelaide, SA 5005 (Australia)

2015-08-15

Al{sub 2}O{sub 3} and Al{sub 3}Zr reinforced aluminum matrix composites were fabricated from Al and ZrO{sub 2} powders by SiC assisted microwave combustion synthesis. The microstructure and reaction pathways were analyzed by using differential scanning calorimetry (DSC), X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM) and energy dispersive spectroscopy (EDS). The results showed that the heating rate during microwave synthesis was very high and the entire process took several minutes and that the ignition temperature of the reaction was much lower than that of conventional methods. In addition, the resulting microstructure was found to be finer than that prepared by the conventional methods and no cracks can be seen in the Al{sub 3}Zr reinforcements. As such, the newly developed composites have potential for safety-critical applications where catastrophic failure is not tolerated.

X-ray structural study of Nd[N(CN)2]3x2OP(NMe2)3

International Nuclear Information System (INIS)

Kapshuk, A.A.; Skopenko, V.V.

1985-01-01

The results of X-ray structure study of Nd(N(CN) 2 ) 3 x2OP(NMe) 2 ) 3 are presented. The crystals are monoclinic: a=12,787(6), b=17.731(9), c=15.302(5) A, γ=114.84(3) deg, Z=4, sp.gr. p2 1 /n. The structure is formed of infinite corrugated netting consisting of neodymium atoms, coordinating two OP(NMe 2 ) 3 molecules, and three bidentate-bridge dicyanamide groups. Neodymium coordination number is 8, coordination polyhedron is a distorted twocapped trigonal prism. Certain aspects of crystal chemistry of dicyanamide complexes are discussed

Strengthening Aluminum Alloys for High Temperature Applications Using Nanoparticles of Al203 and Al3-X Compounds (X= Ti, V, Zr)

Science.gov (United States)

Lee, Jonathan A.

2007-01-01

In this paper the effect of nanoparticles A12O3 and A13-X compounds (X= Ti, V, Zr) on the improvement of mechanical properties of aluminum alloys for elevated temperature applications is presented. These nanoparticles were selected based on their chemical stability and low diffusions rates in aluminum matrix at high temperatures. The strengthening mechanism for aluminum alloy is based on the mechanical blocking of dislocation movements by these nanoparticles. Samples were prepared from A12O3 nanoparticle preforms, which were produced using ceramic injection molding process and pressure infiltrated by molten aluminum. A12O3 nanoparticles can also be homogeneously mixed with aluminum powder and consolidated into samples through hot pressing and sintering. On the other hand, the Al3-X nanoparticles are produced as precipitates via in situ reactions with molten aluminum alloys using conventional casting techniques. The degree of alloy strengthening using nanoparticles will depend on the materials, particle size, shape, volume fraction, and mean inter-particle spacing.

Novel solid-state synthesis of α-Fe and Fe3O4 nanoparticles embedded in a MgO matrix

Science.gov (United States)

Schneeweiss, O.; Zboril, R.; Pizurova, N.; Mashlan, M.; Petrovsky, E.; Tucek, J.

2006-01-01

Thermally induced reduction of amorphous Fe2O3 nanopowder (2-3 nm) with nanocrystalline Mg (~20 nm) under a hydrogen atmosphere is presented as a novel route to obtain α-Fe and Fe3O4 magnetic nanoparticles dispersed in a MgO matrix. The phase composition, structural and magnetic properties, size and morphology of the nanoparticles were monitored by x-ray diffraction, 57Fe Mössbauer spectroscopy at temperatures of 24-300 K, transmission electron microscopy and magnetic measurements. Spherical magnetite nanoparticles prepared at a reaction temperature of 300 °C revealed a well-defined structure, with a ratio of tetrahedral to octahedral Fe sites of 1/2 being common for the bulk material. A narrow particle size distribution (20-30 nm) and high saturation magnetization (95 ± 5 A m2 kg-1) predispose the magnetite nanoparticles to various applications, including magnetic separation processes. The Verwey transition of Fe3O4 nanocrystals was found to be decreased to about 80 K. The deeper reduction of amorphous ferric oxide at 600 °C allows α-Fe (40-50 nm) nanoparticles to be synthesized with a coercive force of about 30 mT. They have a saturation magnetization 2.2 times higher than that of synthesized magnetite nanoparticles, which corresponds well with the ratio usually found for the pure bulk phases. The magnetic properties of α-Fe nanocrystals combined with the high chemical and thermal stability of the MgO matrix makes the prepared nanocomposite useful for various magnetic applications.

Synthesis and crystal structure of the solid solution Co3(SeO3)3-x(PO3OH)x(H2O) involving crystallographic split positions of Se4+ and P5+.

Science.gov (United States)

Zimmermann, Iwan; Johnsson, Mats

2013-10-21

Three new cobalt selenite hydroxo-phosphates laying in the solid solution Co3(SeO3)3-x(PO3OH)x(H2O), with x = 0.8, x = 1.0, and x = 1.2 are reported. Single crystals were obtained by hydrothermal synthesis and the crystal structure was determined by single crystal X-ray diffraction. The structure can be described as a 3D framework having selenite and hydroxo-phosphate groups protruding into channels in the crystal structure. Se(4+) and P(5+) share a split position in the structure so that either SeO3 groups having a stereochemically active lone pair or tetrahedrally coordinated PO3OH groups are present. The OH-group is thus only present when the split position is occupied by P(5+). The crystal water is coordinated to a cobalt atom and TG and IR measurements show that the water and hydroxyl groups leave the structure at unusually high temperatures (>450 °C). Magnetic susceptibility measurements show antiferromagnetic coupling below 16 K and a magnetic moment of 4.02(3) μB per Co atom was observed.

Block 3 X-band receiver-exciter

Science.gov (United States)

Johns, C. E.

1987-01-01

The development of an X-band exciter, for use in the X-Band Uplink Subsystem, was completed. The exciter generates the drive signal for the X-band transmitter and also generates coherent test signals for the S- and X-band Block 3 translator and a Doppler reference signal for the Doppler extractor system. In addition to the above, the exciter generates other reference signals that are described. Also presented is an overview of the exciter design and some test data taken on the prototype. A brief discussion of the Block 3 Doppler extractor is presented.

Tunneling magnetoresistance in nanogranular La1-xSrxMnO3 (x∼0.5

Directory of Open Access Journals (Sweden)

Jiří Hejtmánek

2017-05-01

Full Text Available Electric transport and magnetic studies were performed on the La1-xSrxMnO3 (x=0.45-0.55 perovskite manganites. The main focus was given to the nanogranular ceramics of average x=0.47 composition, compacted by spark plasma sintering of molten salt synthesized nanoparticles. This sample can be viewed as a two-phase composite where FM manganite granules are embedded in AFM manganite matrix. The magnetoconductance data observed on this sample reveal a coexistence of distinct low- and high-field contributions, related to the field-induced alignment of ferromagnetic (FM granules and the spin canting in antiferromagnetic (AFM matrix, respectively. Their analysis confirms the theoretically predicted scaling of the low-field effect with squared reduced magnetization and provides also a quantitative comparison between the linear coefficient of high-field magnetoconductance and paraprocess seen in the magnetization measurement.

Barium aluminides BaxAl5(x=3,3.5,4)

International Nuclear Information System (INIS)

Jehle, Michael; Scherer, Harald; Wendorff, Marco; Roehr, Caroline

2009-01-01

Three aluminides of the series Ba x Al 5 (x=3,3.5,4) were synthesized from stoichiometric ratios of the elements in Ta crucibles. The crystal structure of the new compound Ba 7 Al 10 was determined using single crystal X-ray data (space group R3-barm, a=604.23(9), c=4879.0(12)pm, Z=3, R1=0.0325). The compound exhibits Al Kagome (3.6.3.6.) nets in which half of the triangles form the basis of trigonal bipyramids Al 5 . The apical Al are thus three-bonded assuming a charge of -2 ( 27 Al-NMR chemical shift δ=660pm), whereas the Al atoms of the basal triangle (i.e. of the Kagome net) are four-bonded and thus of formal charge -1(δ=490ppm). The total charge of the anion is thus exactly compensated by the Ba cations, i.e. the compound can be interpreted as an electron precise Zintl phase, exhibiting a distinct pseudo-band gap at the Fermi level of the calculated tDOS. According to the total formula, the structure displays a combination the stacking sequences of Ba 3 Al 5 and Ba 4 Al 5 , the structures of which have been redetermined with current methods (both hexagonal with space group P6 3 /mmc; Ba 3 Al 5 : a=606.55(7), c=1461.8(2)pm, Z=2, R1=0.0239; Ba 4 Al 5 : a=609.21(7), c=1775.8(3)pm, Z=2, R1=0.0300). These three compounds with slightly different electron counts but similar polyanions allow to compare the bond lengths, the electronic structures and the overall bonding situation in dependence of positive or negative deviation of the electron count in relation to the novel formally electron precise Zintl compound Ba 7 Al 10 . - Al 5 layers of Kagome nets in the new binary electron precise Zintl compound Ba 3.5 Al 5 , also found in Ba 3 Al 5 and Ba 4 Al 5 .

Why is alpha-actinin-3 deficiency so common in the general population? The evolution of athletic performance.

Science.gov (United States)

North, Kathryn

2008-08-01

'We can now explain how this common genetic variation influences athletic performance as well as why it has become so common in the general population. There is a fascinating link between factors that influence survival in ancient humans and the factors that contribute to athletic abilities in modern man.' The human ACTN3 gene encodes the protein alpha-actinin-3, a component of the contractile apparatus in fast skeletal muscle fibers. In 1999, we identified a common polymorphism in ACTN3 (R577X) that results in absence of alpha-actinin-3 in more than one billion people worldwide, despite the ACTN3 gene being highly conserved during human evolution. In 2003, we demonstrated that ACTN3 genotype influences elite athletic performance, and the association between ACTN3 genotype and skeletal muscle performance has since been replicated in athletes and non-athlete cohorts. We have also studied the evolution of the R577X allele during human evolution and demonstrated that the null (X) allele has undergone strong, recent positive selection in Europeans and Asian populations. We have developed an Actn3 knockout mouse model that replicates alpha-actinin-3 deficiency in humans and has already provided insight into the role of alpha-actinin-3 in the regulation of skeletal muscle metabolism, fibre size, muscle mass and contractile properties. In particular, mouse muscle lacking alpha-actinin-3 uses energy more efficiently, with the fast fibers displaying metabolic and contractile properties of slow oxidative fibers. While this favors endurance activities, the trade off is that the muscle cannot generate the rapid contractions needed to excel in sprinting. We propose that the shift towards more efficient aerobic muscle metabolism associated with alpha-actinin-3 deficiency also underlies the adaptive benefit of the 577X allele. Our future studies will focus on the effect of ACTN3 genotype on response to exercise and ageing, and the onset and severity of muscle disease phenotype.

Properties of half metallic (Ba0.8Sr0.2)2-x La2x/3x/3FeMoO6 double perovskites

International Nuclear Information System (INIS)

Serrate, D.; De Teresa, J.M.; Blasco, J.; Morellon, L.; Ibarra, M.R.

2005-01-01

Previous work in (Ba 0.8 Sr 0.2 ) 2- x La x FeMoO 6 and Ba 1+ x Sr 1-3 x La 2 x FeMoO 6 have stated electron doping as the most important parameter in terms of T c enhancement. Here we report complementary structural, magnetic and transport properties, say a series where there is no doping and only structural parameters are changed: (Ba 0.8 Sr 0.2 ) 2- x La 2 x /3 x /3 FeMoO 6 . We propose a complete phase diagram where structural and bandfilling impact on the Curie temperature is clearly evidenced

U(1) x U(1) x U(1) symmetry of the Kimura 3ST model and phylogenetic branching processes

International Nuclear Information System (INIS)

Bashford, J D; Jarvis, P D; Sumner, J G; Steel, M A

2004-01-01

An analysis of the Kimura 3ST model of DNA sequence evolution is given on the basis of its continuous Lie symmetries. The rate matrix commutes with a U(1) x U(1) x U(1) phase subgroup of the group GL(4) of 4 x 4 invertible complex matrices acting on a linear space spanned by the four nucleic acid base letters. The diagonal 'branching operator' representing speciation is defined, and shown to intertwine the U(1) x U(1) x U(1) action. Using the intertwining property, a general formula for the probability density on the leaves of a binary tree under the Kimura model is derived, which is shown to be equivalent to established phylogenetic spectral transform methods. (letter to the editor)

3D cancer cell migration in a confined matrix

Science.gov (United States)

Alobaidi, Amani; Sun, Bo

Cancer cell migration is widely studied in 2D motion, which does not mimic the invasion processes in vivo. More recently, 3D cell migration studies have been performed. The ability of cancer cells to migrate within the extracellular matrix depends on the physical and biochemical features of the extracellular matrix. We present a model of cell motility in confined matrix geometry. The aim of the study is to study cancer migration in collagen matrix, as a soft tissue, to investigate their motility within the confined and surrounding collagen environment. Different collagen concentrations have been used to show the ability of these cancer cells to move through such a complex structure by measuring Cancer cell migration velocity as well as the displacement. Graduate student physics department.

Concurrent ionic migration and electronic effects at the memristive TiO x /La1/3Ca2/3MnO3-x interface

Science.gov (United States)

Román Acevedo, W.; Ferreyra, C.; Sánchez, M. J.; Acha, C.; Gay, R.; Rubi, D.

2018-03-01

The development of reliable redox-based resistive random-access memory devices requires understanding and disentangling concurrent effects present at memristive interfaces. We report on the fabrication and electrical characterization of TiO x /La1/3Ca2/3MnO3-x microstructured interfaces and on the modeling of their memristive behavior. We show that a careful tuning of the applied external electrical stimuli allows controlling the redox process between both layers, obtaining multilevel non-volatile resistance states. We simulate the oxygen vacancies dynamics at the interface between both oxides, and successfully reproduce the experimental electrical behavior after the inclusion of an electronic effect, related to the presence of an n-p diode at the interface. The formation of the diode is due to the n- and p-character of TiO x and La1/3Ca2/3MnO3-x , respectively. Our analysis indicates that oxygen vacancies migration between both layers is triggered after the diode is polarized either in forward mode or in reverse mode above breakdown. Electrical measurements at different temperatures suggest that the diode can be characterized as Zener-type. The advantages of our junctions for their implementation in RRAM devices are finally discussed.

Microstructure and mechanical properties of stir cast ZX51/Al{sub 2}O{sub 3}p magnesium matrix composites

Energy Technology Data Exchange (ETDEWEB)

Rahmany-Gorji, Reza, E-mail: r_rahmany@ymail.com [Materials Engineering Department, Faculty of Mechanical Engineering, Shahid Rajaee Teacher Training University, Tehran (Iran, Islamic Republic of); Alizadeh, Ali [Faculty of Materials and Manufacturing Processes, MUT, Tehran (Iran, Islamic Republic of); Jafari, Hassan [Materials Engineering Department, Faculty of Mechanical Engineering, Shahid Rajaee Teacher Training University, Tehran (Iran, Islamic Republic of)

2016-09-30

Magnesium matrix composites can overcome the limitations of magnesium and its alloys. This paper investigates the effect of adding Al{sub 2}O{sub 3} microparticles on microstructure and mechanical response of ZX51 alloy-matrix composites. Stir casting process was chosen due largely to its low cost to fabricate the novel ZX51/Al{sub 2}O{sub 3}p composites. Scanning electron microscopy, energy dispersive spectroscopy, and X-ray diffractometry were used in order to analyze the microstructure of as-cast composites. Tension, compression, and Brinell hardness tests were performed to determine mechanical properties of the composites. It was revealed that the microstructure of matrix alloy is composed of α-Mg grains and (α-Mg+Ca{sub 2}Mg{sub 6}Zn{sub 3}) eutectic mixture distributed predominantly along grain boundaries. The addition of Al{sub 2}O{sub 3}p brought about a marked grain refinement and also introduced slight amounts of porosity. The results showed that with increasing volume percentage of Al{sub 2}O{sub 3}p, hardness and yield strength increase while tensile strength, compressive strength, and ductility decrease; in consequence, toughness decreases as well.

Pulsed laser deposition of epitaxial Sr(RuxSn1-x)O3 thin film electrodes and KNbO3/Sr(RuxSn1-x)O3 bilayers

International Nuclear Information System (INIS)

Christen, H.M.; Boatner, L.A.; English, L.Q.; Geea, L.A.; Marrero, P.J.; Norton, D.P.

1995-01-01

Sr(Ru x Sn 1-x ) 3 is proposed as a new conducting oxide for use in epitaxial multilayer structures. The Sr(Ru o 48 Sn 0.52 )0 3 composition exhibits an excellent lattice match with (100)-oriented KTaO 3 , and films of this composition grown by pulsed laser deposition on KTaO 3 , SrTiO 3 , and LaAlO 3 substrates have been analyzed by X-ray diffraction, Rutherford backscattering/ion channeling, and resistivity measurements. Epitaxial KNbO 3 /Sr(Ru 0.48 Sn 0.52 )O 3 bilayers have been successfully grown

Influence of Fe doped on the magnetocaloric behavior of La_{{2}/{3}} Ca_{{1}/{3}} Mn1-x Fe x O3 compounds: a Monte Carlo simulation

Science.gov (United States)

Alzate-Cardona, J. D.; Barco-Rios, H.; Restrepo-Parra, E.

2018-02-01

The magnetocaloric behavior of La{2/{3}} Ca{1/{3}} Mn1-x Fe x O3 for x  =  0.00, 0.02, 0.03, 0.05, 0.07, 0.08 and 0.10 under the influence of an external magnetic field was simulated and analyzed. Simulations were carried out using the Monte Carlo method and the classical Heisenberg model under the Metropolis algorithm. These mixed valence manganites are characterized by having three types of magnetic ions corresponding to Mn4+≤ft(S=\\frac{3}{2}\\right) , which are bonded with Ca2+ , and Mneg3+ and Mneg\\prime3+ (S=2) , related to La3+ . The Fe ions were randomly included, replacing Mn ions. With this model, the magnetic entropy change, Δ S , in an isothermal process was determined. -Δ Sm showed maximum peaks around the paramagnetic-ferromagnetic transition temperature, which depends on Fe doping. Relative cooling power was computed for different Fe concentrations varying the magnetic applied field. Our model and results show that the Fe doping decreases the magnetocaloric effect in the La{2/{3}} Ca{1/{3}} Mn1-x Fe x O3, making this a bad candidate for magnetic refrigeration. The strong dependence of the magnetocaloric behavior on Fe doping and the external magnetic field in La{2/{3}} Ca{1/{3}} Mn1-x Fe x O3 can boost these materials for the future technological applications.

Polarization Behavior of Squeeze Cast Al2O3 Fiber Reinforced Aluminum Matrix Composites

International Nuclear Information System (INIS)

Ham, S. H.; Kang, Y. C.; Cho, K. M.; Park, I. M.

1992-01-01

Electrochemical polarization behavior of squeeze cast Al 2 O 3 short fiber reinforced Al alloy matrix composites was investigated for the basic understanding of the corrosion properties of the composites. The composites were fabricated with variations of fiber volume fraction and matrix alloys. It was found that the reinforced composites are more susceptible to corrosion attack than the unreinforced matrix alloys in general. Corrosion resistance shows decreasing tendency with increasing Al 2 O 3 fiber volume fraction in AC8A matrix. Effect of the matrix alloys revealed that the AC8A Al matrix composite is less susceptible to corrosion attack than the 2024 and 7075 Al matrix composites. Effect of plastic deformation on electrochemical polarization behavior of the squeeze cast Al/Al 2 O 3 composites was examined after extrusion of AC8A-10v/o Al 2 O 3 . Result shows that corrosion resistance is deteriorated after plastic deformation

Crystal structure of Sm(NO3)3x6H2O

International Nuclear Information System (INIS)

Espenbetov, A.A.; Gerr, R.G.; Struchkov, Yu.T.; Sal'nikova, N.A.; Akimov, V.M.; Odinets, Z.K.

1985-01-01

X-ray diffraction study of a salt, prepared when mixing concentrated nitric acid solutions of NaNO 3 and Sm(NO 3 ) 3 , has been carried out. It is established, that the salt is a concretion of two crystals: NaNO 3 and Sm(NO 3 ) 3 x6H 2 O (1). X-ray diffraction study of 1 is carried out (lambda Mo, diffractometer, 1511 reflections, the method of heavy atom, the least square method in anisotropic approximation up to R=0.0348). The crystals of 1 are triclinic: a=6.755, b=9.168, c=11.684 A, α=69.93, β=88.86, γ=69.28, Z=2, Fedorov group P anti 1. Symmetery of 10-vertex coordination polyhedron (CP) of Sm atom is close to Csub(s). Sm atom coordination can be described as 4;5:1. Four H 2 O molecules are included into CP, at the expense of two remaining H 2 O molecules CP are bound with each other

Disk Disruptions and X-ray Intensity Excursions in Cyg X-2, LMC X-3 and Cyg X-3

Science.gov (United States)

Boyd, P. T.; Smale, A. P.

2001-05-01

The RXTE All Sky Monitor soft X-ray light curves of many X-ray binaries show long-term intensity variations (a.k.a "superorbital periodicities") that have been ascribed to precession of a warped, tilted accretion disk around the X-ray source. We have found that the excursion times between X-ray minima in Cyg X-2 can be characterized as a series of integer multiples of the 9.8 binary orbital period, (as opposed to the previously reported stable 77.7 day single periodicity, or a single modulation whose period changes slowly with time). While the data set is too short for a proper statistical analysis, it is clear that the length of any given intensity excursion cannot be used to predict the next (integer) excursion length in the series. In the black hole candidate system LMC X-3, the excursion times are shown to be related to each other by rational fractions. We find that the long term light curve of the unusual galactic X-ray jet source Cyg X-3 can also be described as a series of intensity excursions related to each other by integer multiples of a fundamental underlying clock. In the latter cases, the clock is apparently not related to the known binary periods. A unified physical model, involving both an inclined accretion disk and a fixed-probability disk disruption mechanism is presented, and compared with three-body scattering results. Each time the disk passes through the orbital plane it experiences a fixed probability P that it will disrupt. This model has testable predictions---the distribution of integers should resemble that of an atomic process with a characteristic half life. Further analysis can support or refute the model, and shed light on what system parameters effectively set the value of P.

Complex interactions between human myoblasts and the surrounding 3D fibrin-based matrix.

Directory of Open Access Journals (Sweden)

Stéphane Chiron

Full Text Available Anchorage of muscle cells to the extracellular matrix is crucial for a range of fundamental biological processes including migration, survival and differentiation. Three-dimensional (3D culture has been proposed to provide a more physiological in vitro model of muscle growth and differentiation than routine 2D cultures. However, muscle cell adhesion and cell-matrix interplay of engineered muscle tissue remain to be determined. We have characterized cell-matrix interactions in 3D muscle culture and analyzed their consequences on cell differentiation. Human myoblasts were embedded in a fibrin matrix cast between two posts, cultured until confluence, and then induced to differentiate. Myoblasts in 3D aligned along the longitudinal axis of the gel. They displayed actin stress fibers evenly distributed around the nucleus and a cortical mesh of thin actin filaments. Adhesion sites in 3D were smaller in size than in rigid 2D culture but expression of adhesion site proteins, including α5 integrin and vinculin, was higher in 3D compared with 2D (p<0.05. Myoblasts and myotubes in 3D exhibited thicker and ellipsoid nuclei instead of the thin disk-like shape of the nuclei in 2D (p<0.001. Differentiation kinetics were faster in 3D as demonstrated by higher mRNA concentrations of α-actinin and myosin. More important, the elastic modulus of engineered muscle tissues increased significantly from 3.5 ± 0.8 to 7.4 ± 4.7 kPa during proliferation (p<0.05 and reached 12.2 ± 6.0 kPa during differentiation (p<0.05, thus attesting the increase of matrix stiffness during proliferation and differentiation of the myocytes. In conclusion, we reported modulations of the adhesion complexes, the actin cytoskeleton and nuclear shape in 3D compared with routine 2D muscle culture. These findings point to complex interactions between muscle cells and the surrounding matrix with dynamic regulation of the cell-matrix stiffness.

Inhibition of microRNA-214-5p promotes cell survival and extracellular matrix formation by targeting collagen type IV alpha 1 in osteoblastic MC3T3-E1 cells.

Science.gov (United States)

Li, Q S; Meng, F Y; Zhao, Y H; Jin, C L; Tian, J; Yi, X J

2017-08-01

This study aimed to investigate the functional effects of microRNA (miR)-214-5p on osteoblastic cells, which might provide a potential role of miR-214-5p in bone fracture healing. Blood samples were obtained from patients with hand fracture or intra-articular calcaneal fracture and from healthy controls (HCs). Expression of miR-214-5p was monitored by qRT-PCR at day 7, 14 and 21 post-surgery. Mouse osteoblastic MC3T3-E1 cells were transfected with antisense oligonucleotides (ASO)-miR-214-5p, collagen type IV alpha 1 (COL4A1) vector or their controls; thereafter, cell viability, apoptotic rate, and the expression of collagen type I alpha 1 (COL1A1), type II collagen (COL-II), and type X collagen (COL-X) were determined. Luciferase reporter assay, qRT-PCR, and Western blot were performed to ascertain whether COL4A1 was a target of miR-214-5p. Plasma miR-214-5p was highly expressed in patients with bone fracture compared with HCs after fracture (p extracellular matrix (ECM) formation of osteoblastic MC3T3-E1 cells by targeting COL4A1. Cite this article: Q. S. Li, F. Y. Meng, Y. H. Zhao, C. L. Jin, J. Tian, X. J. Yi. Inhibition of microRNA-214-5p promotes cell survival and extracellular matrix formation by targeting collagen type IV alpha 1 in osteoblastic MC3T3-E1 cells. Bone Joint Res 2017;6:464-471. DOI: 10.1302/2046-3758.68.BJR-2016-0208.R2. © 2017 Yi et al.

Form factors in quantum integrable models with GL(3)-invariant R-matrix

Energy Technology Data Exchange (ETDEWEB)

Pakuliak, S., E-mail: pakuliak@theor.jinr.ru [Laboratory of Theoretical Physics, JINR, 141980 Dubna, Moscow Reg. (Russian Federation); Moscow Institute of Physics and Technology, 141700 Dolgoprudny, Moscow Reg. (Russian Federation); Institute of Theoretical and Experimental Physics, 117259 Moscow (Russian Federation); Ragoucy, E., E-mail: eric.ragoucy@lapth.cnrs.fr [Laboratoire de Physique Théorique LAPTH, CNRS and Université de Savoie, BP 110, 74941 Annecy-le-Vieux Cedex (France); Slavnov, N.A., E-mail: nslavnov@mi.ras.ru [Steklov Mathematical Institute, Moscow (Russian Federation)

2014-04-15

We study integrable models solvable by the nested algebraic Bethe ansatz and possessing GL(3)-invariant R-matrix. We obtain determinant representations for form factors of off-diagonal entries of the monodromy matrix. These representations can be used for the calculation of form factors and correlation functions of the XXX SU(3)-invariant Heisenberg chain.

Gold-coated iron nanoparticles in transparent Si{sub 3}N{sub 4} matrix thin films

Energy Technology Data Exchange (ETDEWEB)

Sanchez-Marcos, J. [Consejo Superior de Investigaciones Cientificas, Instituto de Ciencia de Materiales de Madrid (Spain); Cespedes, E. [Keele University, Institute for Science and Technology in Medicine, Guy Hilton Research Centre (United Kingdom); Jimenez-Villacorta, F. [Northeastern University, Department of Chemical Engineering (United States); Munoz-Martin, A. [Universidad Autonoma de Madrid, Centro de Microanalisis de Materiales (Spain); Prieto, C., E-mail: cprieto@icmm.csic.es [Consejo Superior de Investigaciones Cientificas, Instituto de Ciencia de Materiales de Madrid (Spain)

2013-06-15

A new method to prepare thin films containing gold-coated iron nanoparticles is presented. The ternary Fe-Au-Si{sub 3}N{sub 4} system prepared by sequential sputtering has revealed a progressive variation of microstructures from Au/Fe/Au/Si{sub 3}N{sub 4} multilayers to iron nanoparticles. Microstructural characterization by transmission electron microscopy, analysis of the magnetic properties and probing of the iron short-range order by X-ray absorption spectroscopy confirm the existence of a gold-coated iron nanoparticles of 1-2 nm typical size for a specific range of iron and gold contents per layer in the transparent silicon nitride ceramic matrix.

Neutron structural studies of La3.5-x-y(Y)yBa3.5-xCa2xCu7Oz (x = y = 0.0 and 0.5) system

International Nuclear Information System (INIS)

Subbarao, M.V.; Kulkarni, R.G.; Rajagopal, H.; Sequeira, A.S.

1997-01-01

By mixing equal amounts of La 4-x Ca x Ba 3 Cu 7 O z and La 3 Ba 4-x Ca x Cu 7 O z in the proportion of 1 : 1, a series of superconductors part of La replaced by Y with the nominal composition of La 3.5-x-y )(Y) y Ba 3.-5-x Ca 2x Cu 7 O z (LYCP) have been prepared. Two samples with x = y = 0.0 (A) and x = y = 0.5 (B) characterized by x-ray diffraction display tetragonal triple perovskite structure. In order to investigate the effect of substituents (Ca/Y) on structure of this system, neutron diffraction measurements have been carried out at 300 K and λ n =1.216A at Dhruva reactor

Observation of divergent La{sup 3+} ion dilute effect in two series of 3-D fluorescent lanthanide-MOFs-based molecular alloys RE{sub x}La{sub 1−x}–EBTC (RE{sup 3+}=Eu{sup 3+} or Tb{sup 3+}; EBTC{sup 4−}=1,1′-ethynebenzene-3,3′,5,5′-etracarboxylate)

Energy Technology Data Exchange (ETDEWEB)

Zhai, Lu [State Key Laboratory of Materials-Oriented Chemical Engineering and College of Science, Nanjing Tech University, Nanjing 210009 (China); State Key Laboratory of Coordination Chemistry, School of Chemistry and Chemical Engineering, Nanjing University, Nanjing 210093 (China); Zhang, Wen-Wei, E-mail: wwzhang@nju.edu.cn [State Key Laboratory of Coordination Chemistry, School of Chemistry and Chemical Engineering, Nanjing University, Nanjing 210093 (China); Ren, Xiao-Ming, E-mail: xmren@njtech.edu.cn [State Key Laboratory of Materials-Oriented Chemical Engineering and College of Science, Nanjing Tech University, Nanjing 210009 (China); Zuo, Jing-Lin [State Key Laboratory of Coordination Chemistry, School of Chemistry and Chemical Engineering, Nanjing University, Nanjing 210093 (China)

2015-10-15

The lanthanide metal-organic frameworks (MOFs) [Ln{sub 2}(EBTC){sub 1.5}(CH{sub 3}OH){sub 4}]·6H{sub 2}O are isostructural to each other, where EBTC{sup 4−}=1,1′-ethynebenzene-3,3′,5,5′-tetracarboxylate; Ln{sup 3+}=La{sup 3+}, Eu{sup 3+} and Tb{sup 3+}; and the corresponding MOF is abbreviated as Ln–EBTC. MOFs Eu–EBTC and Tb–EBTC emit intense red and green luminescence (visible by bare eyes), respectively. The molecular alloys of Eu{sub x}La{sub 1−x}–EBTC and Tb{sub x}La{sub 1−x}–EBTC have been successfully prepared by mixing Eu{sup 3+}/Tb{sup 3+} and La{sup 3+} salts with the desired molar ratio in the starting material. Two series of Eu{sub x}La{sub 1−x}–EBTC and Tb{sub x}La{sub 1−x}–EBTC molecular alloys are isomorphic to the parent Ln–EBTC MOFs, while exhibit divergent La{sup 3+} ion diluting effect, namely, with increasing the relative amount of La{sup 3+}, the intensity of characteristic emission arising from Tb{sup 3+} ion monotonely increases in Tb{sub x}La{sub 1−x}–EBTC molecular alloys, whereas that of Eu{sup 3+} ion shows non-monotone decrease in Eu{sub x}La{sub 1−x}–EBTC molecular alloys. The possible origin is discussed for such a divergent behavior between Eu{sub x}La{sub 1−x}–EBTC and Tb{sub x}La{sub 1−x}–EBTC molecular alloys. - Graphical abstract: Two series of 3-D fluorescent lanthanide-MOFs-based molecular alloys RE{sub x}La{sub 1−x}–EBTC (RE{sup 3+}=Eu{sup 3+} or Tb{sup 3+}; EBTC{sup 4−}=1,1′-ethynebenzene-3,3′,5,5′-tetracarboxylate) have been successfully prepared by mixing Eu{sup 3+}/Tb{sup 3+} and La{sup 3+} salts with the desired molar ratio in the starting material and showed photoluminescence property with divergent La{sup 3+} ion dilute effect. - Highlights: • 3-D molecular alloys of Eu{sub x}La{sub 1−x}–EBTC and Tb{sub x}La{sub 1−x}–EBTC were prepared. • They are isomorphic to the parent Ln–EBTC MOFs. • They show photoluminescence property with divergent La

Trapping charges at grain boundaries and degradation of CH3NH3Pb(I1-x Br x )3 perovskite solar cells

Science.gov (United States)

Phuong Nguyen, Bich; Kim, Gee Yeong; Jo, William; Kim, Byeong Jo; Jung, Hyun Suk

2017-08-01

The electrical properties of CH3NH3Pb(I1-x Br x )3 (x = 0.13) perovskite materials were investigated under ambient conditions. The local work function and the local current were measured using Kelvin probe force microscopy and conductive atomic force microscopy, respectively. The degradation of the perovskite layers depends on their grain size. As the material degrades, an additional peak in the surface potential appears simultaneously with a sudden increase and subsequent relaxation of the local current. The potential bending at the grain boundaries and the intragrains is the most likely reason for the change of the local current surface of the perovskite layers. The improved understanding of the degradation mechanism garnered from this study helps pave the way toward an improved photo-conversion efficiency in perovskite solar cells.

The 3-loop pure singlet heavy flavor contributions to the structure function F{sub 2}(x,Q{sup 2}) and the anomalous dimension

Energy Technology Data Exchange (ETDEWEB)

Ablinger, J. [Research Institute for Symbolic Computation (RISC), Johannes Kepler University, Altenbergerstraße 69, A-4040 Linz (Austria); Behring, A.; Blümlein, J.; De Freitas, A. [Deutsches Elektronen-Synchrotron, DESY, Platanenallee 6, D-15738 Zeuthen (Germany); Manteuffel, A. von [PRISMA Cluster of Excellence, Institute of Physics, J. Gutenberg University, D-55099 Mainz (Germany); Schneider, C. [Research Institute for Symbolic Computation (RISC), Johannes Kepler University, Altenbergerstraße 69, A-4040 Linz (Austria)

2015-01-15

The pure singlet asymptotic heavy flavor corrections to 3-loop order for the deep-inelastic scattering structure function F{sub 2}(x,Q{sup 2}) and the corresponding transition matrix element A{sub Qq}{sup (3),PS} in the variable flavor number scheme are computed. In Mellin-N space these inclusive quantities depend on generalized harmonic sums. We also recalculate the complete 3-loop pure singlet anomalous dimension for the first time. Numerical results for the Wilson coefficients, the operator matrix element and the contribution to the structure function F{sub 2}(x,Q{sup 2}) are presented.

ECAP consolidation of Al matrix composites reinforced with in-situ γ-Al{sub 2}O{sub 3} nanoparticles

Energy Technology Data Exchange (ETDEWEB)

Casati, R., E-mail: riccardo.casati@polimi.it [Department of Mechanical Engineering, Politecnico di Milano, Via La Masa 1, Milano (Italy); Fabrizi, A. [Department of Management and Engineering, Università di Padova, Stradella S. Nicola 3, Vicenza (Italy); Tuissi, A. [CNR-IENI, Corso Promessi Sposi 29, Lecco (Italy); Xia, K. [Department of Mechanical Engineering, University of Melbourne, Victoria 3010 (Australia); Vedani, M. [Department of Mechanical Engineering, Politecnico di Milano, Via La Masa 1, Milano (Italy)

2015-11-11

This work is aimed at proposing a method to prepare aluminum matrix composites reinforced with γ-Al{sub 2}O{sub 3} nanoparticles and at describing the effects of an in-situ reaction on the resulting nano-reinforcement dispersed throughout the metal matrix. Al nano- and micro-particles were used as starting materials. They were consolidated by equal channel angular pressing (ECAP) in as-received conditions and after undergoing high-energy ball milling. Further, γ-Al{sub 2}O{sub 3} reinforcing nanoparticles were produced in-situ from the hydroxide layer that covered the Al powder particles. The powder particle morphology and the composites microstructures were investigated by electron microscopy. The transformation process was monitored by X-ray diffraction, differential scanning calorimetry and thermo-gravimetric analysis.

“Wrapping” X3DOM around Web Audio API

Directory of Open Access Journals (Sweden)

Andreas Stamoulias

2015-12-01

Full Text Available Spatial sound has a conceptual role in the Web3D environments, due to highly realism scenes that can provide. Lately the efforts are concentrated on the extension of the X3D/ X3DOM through spatial sound attributes. This paper presents a novel method for the introduction of spatial sound components in the X3DOM framework, based on X3D specification and Web Audio API. The proposed method incorporates the introduction of enhanced sound nodes for X3DOM which are derived by the implementation of the X3D standard components, enriched with accessional features of Web Audio API. Moreover, several examples-scenarios developed for the evaluation of our approach. The implemented examples established the achievability of new registered nodes in X3DOM, for spatial sound characteristics in Web3D virtual worlds.

Search for UHE emission from Cygnus X-3

International Nuclear Information System (INIS)

Stark, M.J.

1993-01-01

Data from the CYGNUS experiment has been searched for evidence of ultra high energy (UHE) emission from Cygnus X-3. An upper limit to continuous flux from the source is given. In addition, we find no evidence for episodic emission from Cygnus X-3 on any time scale from 3.3 minutes to 4 years. The results of searches for periodic emission from Cygnus X-3 will be presented at the conference

Giant magnetoresistance on low field in non-stoichiometric La2/3Ca1/3Mn1-xO3

International Nuclear Information System (INIS)

Zhao Lifeng; Chen Wei; Shang Jingling; Chen Lei; Liu Sheng; Xia Zhengcai; Yuan Songliu

2005-01-01

Electrical transport and low field magnetoresistance (MR) are reported in the La 2/3 Ca 1/3 Mn 1-x O 3 (x = 0-0.16) samples, which are prepared by the sol-gel method followed by a sintering treatment at 1100 0 C. Experimental results show, for x = 0.06, an MR platform is observed in a temperature ∼200 K under the magnetic field of 0.5 T. With an increase in x, the MR effect gets augmented. For the sample with x = 0.16, its MR peak is as high as 50%

The inverse perovskite nitrides (Sr{sub 3}N{sub 2/3-x})Sn, (Sr{sub 3}N{sub 2/3-x})Pb, and (Sr{sub 3}N)Sb. Flux crystal growth, crystal structures, and physical properties

Energy Technology Data Exchange (ETDEWEB)

Pathak, Manisha; Bobnar, Matej; Ormeci, Alim; Prots, Yurii; Hoehn, Peter [Chemische Metallkunde, Max-Planck-Institut fuer Chemische Physik fester Stoffe, Dresden (Germany); Stoiber, Dominik; Niewa, Rainer [Institut fuer Anorganische Chemie, Universitaet Stuttgart (Germany)

2018-02-15

Black single crystals with metallic luster of (Sr{sub 3}N{sub 2/3-x})E (E = Sn, Pb) and (Sr{sub 3}N)Sb were grown in lithium flux from strontium nitride, Sr{sub 2}N, and tin, lead, or antimony, respectively. Nitrogen deficiency in the tin and the lead compound is a result of the higher ionic charge of the tetrelide ions E{sup 4-} as compared to the antimonide ion Sb{sup 3-}. In contrast to microcrystalline samples from solid state sinter reactions obtained earlier, the flux synthesis induces nitrogen order in the nitrogen deficient tetrelides. The antimony compound crystallizes as inverse cubic perovskite [a = 517.22(5) pm, Z = 1, space group Pm3m, no. 221] with fully occupied nitrogen site, whereas the nitrogen deficient tin and lead compounds exhibit partially ordered arrangements and a certain phase width in respect to nitrogen contents. For the tetrelides, the nitrogen order leads to a cubic 2 x 2 x 2 superstructure [E = Sn: a = 1045.64(8) pm for x = 0, a = 1047.08(7) pm for x = 0.08; and E = Pb: a = 1050.7(1) pm for x = 0, space group Fm3m, no. 225] as derived from single-crystal X-ray diffraction data. The metallic tetrelides show diamagnetic behavior, which is consistent with electronic structure calculations. (copyright 2018 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

Structure, mechanical and magnetic properties of Al4C3 reinforced nickel matrix nanocomposites

Science.gov (United States)

Chaudhari, Alok Kumar; Singh, Dhananjay Kumar; Singh, V. B.

2018-05-01

A new type of nanocomposite, Ni-Al4C3 was prepared using Al4C3 as reinforcement by cathodic co-deposition at different current densities (1.0 to 5.0 A dm‑2) from a nickel acetate-N-methyl formamide (non-aqueous) bath. Influence of current density and incorporation of Al4C3 particles in nickel matrix on the structure and properties of the composite coatings was investigated. Surface morphology and composition of the deposits were determined by SEM and EDAX. Crystallographic structure and orientation of the electrodeposited Ni-Al4C3 composite were studied by x-ray diffraction. Compared to nickel metal, these nanocomposites exhibited finer grains, higher microhardness, improved corrosion resistance and enhanced soft magnetic properties. Composite deposited at higher current densities (>2 A dm‑2) shows mild texturing along (200) plane. The effect of heat treatment on the microstructure, texture and microhardness of the nanocomposites was also investigated.

Metal-semiconductor transition at a comparable resistivity level and positive magnetoresistance in Mn3Mn1-x Pd x N thin films

Science.gov (United States)

Xu, T.; Ji, G. P.; Cao, Z. X.; Ji, A. L.

2018-02-01

Thin films of antiperovskite Mn3Mn1-x Pd x N with x up to 0.36 were grown by reactive magnetron co-sputtering method. All the deposits exhibit a [1 0 0] preferential orientation, with the lattice constant slightly enlarged in samples with ever more Pd atoms partially substituting the MnI atoms in Mn3MnN matrix. The replacement of MnI atoms in antiperovskite structure by Pd atoms, besides reducing the saturation magnetization, also invokes a metal-semiconductor transition which occurs remarkably at a comparable resistivity level. Moreover, a positive magnetoresistance was observed in samples of a high Pd content. These tunable electrical and magnetic properties of ternary antiperovskite compounds might promise some ingenious applications in electronic industry.

Brightly Luminescent and Color-Tunable Colloidal CH3NH3PbX3 (X = Br, I, Cl) Quantum Dots: Potential Alternatives for Display Technology.

Science.gov (United States)

Zhang, Feng; Zhong, Haizheng; Chen, Cheng; Wu, Xian-gang; Hu, Xiangmin; Huang, Hailong; Han, Junbo; Zou, Bingsuo; Dong, Yuping

2015-04-28

Organometal halide perovskites are inexpensive materials with desirable characteristics of color-tunable and narrow-band emissions for lighting and display technology, but they suffer from low photoluminescence quantum yields at low excitation fluencies. Here we developed a ligand-assisted reprecipitation strategy to fabricate brightly luminescent and color-tunable colloidal CH3NH3PbX3 (X = Br, I, Cl) quantum dots with absolute quantum yield up to 70% at room temperature and low excitation fluencies. To illustrate the photoluminescence enhancements in these quantum dots, we conducted comprehensive composition and surface characterizations and determined the time- and temperature-dependent photoluminescence spectra. Comparisons between small-sized CH3NH3PbBr3 quantum dots (average diameter 3.3 nm) and corresponding micrometer-sized bulk particles (2-8 μm) suggest that the intense increased photoluminescence quantum yield originates from the increase of exciton binding energy due to size reduction as well as proper chemical passivations of the Br-rich surface. We further demonstrated wide-color gamut white-light-emitting diodes using green emissive CH3NH3PbBr3 quantum dots and red emissive K2SiF6:Mn(4+) as color converters, providing enhanced color quality for display technology. Moreover, colloidal CH3NH3PbX3 quantum dots are expected to exhibit interesting nanoscale excitonic properties and also have other potential applications in lasers, electroluminescence devices, and optical sensors.

Underground muons from Cygnus X-3

International Nuclear Information System (INIS)

Price, L.E.

1985-01-01

Underground detectors, intended for searches for nucleon decay and other rare processes, have recently begun searching for evidence of astrophysical sources, particularly Cygnus X-3, in the cosmic ray muons they record. Some evidence for signals from Cygnus X-3 has been reported. The underground observations are reported here in the context of previous (surface) observations of the source at high energies. 25 refs., 8 figs

Fabrication of 2-3 YBa2Cu3O7-x/polymer composite with Tc above liquid nitrogen temperature

International Nuclear Information System (INIS)

Wilson, C.M.; Safari, A.

1990-01-01

This paper reports on high T c superconducting oxide woven networks fabricated and used to form YBa 2 Cu 3 O 7-x /polymer composites showing a superconducting resistive transition above liquid nitrogen temperature. The ceramic network was produced by soaking biaxially woven carbon fabric in a solution containing the stoichiometric proportions of Y, Ba, and Cu. Decomposition of the infiltrated carbon fabric and reaction of the remaining oxides resulted in a ceramic replica of the original fabric. The fired networks had a strand diameter ∼100 μm and were embedded in a polymer matrix to produce 2--3 superconducting/polymer composites with a superconducting transition of ∼89 K. Linear shrinkage of the networks was constrained during firing, although the radial shrinkage of the superconducting strands occurred freely. XRD of the networks indicated the presence of BaCO 3 , CuO, and BaCuO 2 as impurity phases

Electrical transport of (1-x)La{sub 0.7}Ca{sub 0.3}MnO{sub 3}+xAl{sub 2}O{sub 3} composites

Energy Technology Data Exchange (ETDEWEB)

Phong, P.T. [Nhatrang Pedagogic College, Khanhhoa, 1st Nguyen Chanh, Nha Trang City, Khanhhoa (Viet Nam); Institute of Material Science, Vietnamese Academy of Science and Technology, 18 Hoang Quoc Viet Road, Cau Giay District, Hanoi (Viet Nam); Khiem, N.V. [Department of Natural Sciences, Hongduc University, 307 Le Lai Street Thanh Hoa City (Viet Nam)], E-mail: nvkhiem2002@yahoo.com; Dai, N.V.; Manh, D.H.; Hong, L.V.; Phuc, N.X. [Institute of Material Science, Vietnamese Academy of Science and Technology, 18 Hoang Quoc Viet Road, Cau Giay District, Hanoi (Viet Nam)

2009-10-15

We report the resistivity ({rho})-temperature (T) patterns in (1-x)La{sub 0,7}Ca{sub 0,3}MnO{sub 3}+xAl{sub 2}O{sub 3} composites (0{<=}x{<=}0.05) over a temperature regime of 50-300 K. Al{sub 2}O{sub 3} addition has increased the resistivity of these composites. The Curie temperature (T{sub C}) is almost independent on the Al{sub 2}O{sub 3} content and is about 250 K for all the samples, while the metal-insulator transition temperature (T{sub MI}) decreases with increasing Al{sub 2}O{sub 3} content. Based on the phenomenological equation for conductivity under a percolation approach, which is dependent on the phase segregation of ferromagnetic metallic clusters and paramagnetic insulating regions, we fitted the experimental data ({rho}-T) from 50 to 300 K and find that the activation barrier increases as Al{sub 2}O{sub 3} content increases.

Preparation and surface characteristics of Re3W matrix scandate cathode: An experimental and theoretical study

Science.gov (United States)

Lai, Chen; Wang, Jinshu; Zhou, Fan; Liu, Wei; Hu, Peng; Wang, Changhao; Wang, Ruzhi; Miao, Naihua

2018-05-01

The Scandia doped thermionic cathodes have received great attention owing to their high electron emission density in past two decades. Here, Scandia doped Re3W matrix scandate (RS) cathodes are fabricated by using Sc2O3 doped Re3W powders that prepared by spray drying method. The micromorphology, surface composition and chemical states of RS cathode are investigated with various modern technologies. It reveals that the reduction temperature of RS powders is dramatically increased by Sc2O3. On the surface of RS cathode, a certain amount of Sc2O3 nanoparticles and barium salt submicron particles are observed. According to the in situ Auger electron spectroscopy analysis, the concentration ratio of Ba:Sc:O is determined to be 2.9:1.1:2.7. The X-ray photoelectron spectroscopy data indicates that low oxidation state of Sc is clearly observed in scandate cathodes. The high atomic ratio of Ba on RS cathode surface is suggested due to the high adsorption of Re3W to Ba. Moreover, RS cathode shows better adsorption to Sc by comparison with conventional tungsten matrix scandate cathode. For RS cathode, the main depletion of Sc is suggested to -OSc desorbing from RS cathode surface. RS cathode is expected to be an impressive thermionic cathode with good emission properties and ion anti-bombarding insensitivity.

Effects of Fe3O4 Magnetic Nanoparticles on the Thermoelectric Properties of Heavy-Fermion YbAl3 Materials

Science.gov (United States)

He, Danqi; Mu, Xin; Zhou, Hongyu; Li, Cuncheng; Ma, Shifang; Ji, Pengxia; Hou, Weikang; Wei, Ping; Zhu, Wanting; Nie, Xiaolei; Zhao, Wenyu

2018-06-01

The magnetic nanocomposite thermoelectric materials xFe3O4/YbAl3 ( x = 0%, 0.3%, 0.6%, 1.0%, and 1.5%) have been prepared by the combination of ultrasonic dispersion and spark plasma sintering process. The nanocomposites retain good chemical stability in the presence of the second-phase Fe3O4. The second-phase Fe3O4 magnetic nanoparticles are distributed on the interfaces and boundaries of the matrix. The x dependences of thermoelectric properties indicate that Fe3O4 magnetic nanoparticles can significantly decrease the thermal conductivity and electrical conductivity. The magnetic nanoparticles embedded in YbAl3 matrix are not only the phonon scattering centers of nanostructures, but also the electron scattering centers due to the Kondo-like effect between the magnetic moment of Fe3O4 nanoparticles and the spin of electrons. The ZT values of the composites are first increased in the x range 0%-1.0% and then decreased when x > 1.0%. The highest ZT value reaches 0.3 at 300 K for the nanocomposite with x = 1.0%. Our work demonstrates that the Fe3O4 magnetic nanoparticles can greatly increase the thermoelectric performance of heavy-fermion YbAl3 thermoelectric materials through simultaneously scattering electrons and phonons.

Polarized Radiative Transfer of a Cirrus Cloud Consisting of Randomly Oriented Hexagonal Ice Crystals: The 3 x 3 Approximation for Non-Spherical Particles

Science.gov (United States)

Stamnes, S.; Ou, S. C.; Lin, Z.; Takano, Y.; Tsay, S. C.; Liou, K.N.; Stamnes, K.

2016-01-01

The reflection and transmission of polarized light for a cirrus cloud consisting of randomly oriented hexagonal columns were calculated by two very different vector radiative transfer models. The forward peak of the phase function for the ensemble-averaged ice crystals has a value of order 6 x 10(exp 3) so a truncation procedure was used to help produce numerically efficient yet accurate results. One of these models, the Vectorized Line-by-Line Equivalent model (VLBLE), is based on the doubling- adding principle, while the other is based on a vector discrete ordinates method (VDISORT). A comparison shows that the two models provide very close although not entirely identical results, which can be explained by differences in treatment of single scattering and the representation of the scattering phase matrix. The relative differences in the reflected I and Q Stokes parameters are within 0.5 for I and within 1.5 for Q for all viewing angles. In 1971 Hansen showed that for scattering by spherical particles the 3 x 3 approximation is sufficient to produce accurate results for the reflected radiance I and the degree of polarization (DOP), and he conjectured that these results would hold also for non-spherical particles. Simulations were conducted to test Hansen's conjecture for the cirrus cloud particles considered in this study. It was found that the 3 x 3 approximation also gives accurate results for the transmitted light, and for Q and U in addition to I and DOP. For these non-spherical ice particles the 3 x 3 approximation leads to an absolute error 2 x 10(exp -6) for the reflected and transmitted I, Q and U Stokes parameters. Hence, it appears to be an excellent approximation, which significantly reduces the computational complexity and burden required for multiple scattering calculations.

Making LULUCF matrix of Korea by Approach 2&3

Science.gov (United States)

Hwang, J.; Jang, R.; Seong, M.; Yim, J.; Jeon, S. W.

2017-12-01

To establish and implement policies in response to climate change, it is very important to identify domestic greenhouse gas emission sources and sinks, and accurately calculate emissions and removals from each source and sink. The IPCC Guideline requires the establishment of six sectors of energy, industrial processes, solvents and other product use, agriculture, Land-Use Change and Forestry (LULUCF) and waste in estimating GHG inventories. LULUCF is divided into 6 categories according to land use, purpose, and type, and then it calculates greenhouse gas emission/absorption amount due to artificial activities according to each land use category and greenhouse gas emission/absorption amount according to land use change. The IPCC Guideline provides three approaches to how to create a LULUCF discipline matrix. According to the IPCC Guidelines, it is a principle to divide into the land use that is maintained and the land use area changed to other lands. However, Korea currently uses Approach 1, which is based on statistical data, it is difficult to detect changed area. Therefore, in this study, we are going to do a preliminary work for constructing the LULUCF matrix at Approach 2 & 3 level. NFI data, GIS, and RS data were used to build the matrix of Approach 2 method by Sampling method. For used for Approach 3, we analyzed the four thematic maps - Cadastral Map, Land Cover Map, Forest Type Map, and Biotope Map - representing land cover and utilization in terms of legal, property, quantitative and qualitative aspects. There is a difference between these maps because their purpose, resolution, timing and spatial range are different. Comparing these maps is important because it can help for decide map which is suitable for constructing the LULUCF matrix.Keywords: LULUCF, GIS/RS, IPCC Guideline, Approach 2&3, Thematic Maps

Photoluminescence of trivalent rare earths in perovskite stacking polytypes Ba/sub 2/Lasub(2-x)REsub(x)/sup 3 +/MgW/sub 2/vacantO/sub 12/, Ba/sub 6/Ysub(2-x)REsub(x)/sup 3 +/W/sub 3/vacantO/sub 18/, and Sr/sub 8/SrGdsub(2-x)REsub(x)/sup 3 +/W/sub 4/vacantO/sub 24/

Energy Technology Data Exchange (ETDEWEB)

Kemmler-Sack, S [Tuebingen Univ. (Germany, F.R.). Lehrstuhl fuer Anorganische Chemie 2

1981-12-01

Rhombohedral 12 L staking polytypes Ba/sub 2/Lasub(2-x)REsub(x)/sup 3 +/MgW/sub 2/vacantO/sub 12/ show with RE/sup 3 +/ = Pr, Sm, Eu, Tb, Dy, Ho, Er, Tm; the 18 L stacking polytypes Ba/sub 6/Ysub(2-x)REsub(x)/sup 3 +/W/sub 3/vacantO/sub 18/ and the polymorphic perovskites Sr/sub 8/SrGdsub(2-x)REsub(x)/sup 3 +/W/sub 4/vacantO/sub 24/ with RE/sup 3 +/ = Sm, Eu, Dy, Ho, Er visible photoluminescence. The concentration dependence and the influence of the coordination number of the rare earth are reported.

3-Aminoquinoline/p-coumaric acid as a MALDI matrix for glycopeptides, carbohydrates, and phosphopeptides.

Science.gov (United States)

Fukuyama, Yuko; Funakoshi, Natsumi; Takeyama, Kohei; Hioki, Yusaku; Nishikaze, Takashi; Kaneshiro, Kaoru; Kawabata, Shin-Ichirou; Iwamoto, Shinichi; Tanaka, Koichi

2014-02-18

Glycosylation and phosphorylation are important post-translational modifications in biological processes and biomarker research. The difficulty in analyzing these modifications is mainly their low abundance and dissociation of labile regions such as sialic acids or phosphate groups. One solution in matrix-assisted laser desorption/ionization (MALDI) mass spectrometry is to improve matrices for glycopeptides, carbohydrates, and phosphopeptides by increasing the sensitivity and suppressing dissociation of the labile regions. Recently, a liquid matrix 3-aminoquinoline (3-AQ)/α-cyano-4-hydroxycinnamic acid (CHCA) (3-AQ/CHCA), introduced by Kolli et al. in 1996, has been reported to increase sensitivity for carbohydrates or phosphopeptides, but it has not been systematically evaluated for glycopeptides. In addition, 3-AQ/CHCA enhances the dissociation of labile regions. In contrast, a liquid matrix 1,1,3,3-tetramethylguanidium (TMG, G) salt of p-coumaric acid (CA) (G3CA) was reported to suppress dissociation of sulfate groups or sialic acids of carbohydrates. Here we introduce a liquid matrix 3-AQ/CA for glycopeptides, carbohydrates, and phosphopeptides. All of the analytes were detected as [M + H](+) or [M - H](-) with higher or comparable sensitivity using 3-AQ/CA compared with 3-AQ/CHCA or 2,5-dihydroxybenzoic acid (2,5-DHB). The sensitivity was increased 1- to 1000-fold using 3-AQ/CA. The dissociation of labile regions such as sialic acids or phosphate groups and the fragmentation of neutral carbohydrates were suppressed more using 3-AQ/CA than using 3-AQ/CHCA or 2,5-DHB. 3-AQ/CA was thus determined to be an effective MALDI matrix for high sensitivity and the suppression of dissociation of labile regions in glycosylation and phosphorylation analyses.

X-ray photoelectron spectroscopy study on Ba1-xEuxTiO3

International Nuclear Information System (INIS)

Lu, D.-Y.; Sugano, Mikio; Sun Xiuyun; Su Wenhui

2005-01-01

X-ray photoelectron spectroscopy is employed to study inner-shell core-level binding energies Eu 4d, Ti 2p and O 1s, Ba 3d for new single-phase Ba 1-x Eu x TiO 3 (0.1 ≤ x ≤ 0.4) samples prepared by solid state reaction at 4.0 GPa and 1090 deg. C. The peak positions of binding energies determined by linear background subtraction and Gaussian fit are presented. XPS analysis indicates that the mixed-valent Eu 3+ /Eu 2+ ions at A-site and Ti 4+ /Ti 3+ ions at B-site coexisted in the Ba 1-x Eu x TiO 3 powder surface, and the amount of Eu 2+ ions is equal to Eu 3+ ions

Síntesis de nanocomposites NTC-13%ZrO2 – (87-xAl2O3-xFe

Directory of Open Access Journals (Sweden)

Legorreta García, F.

2014-04-01

Full Text Available Carbon nanotubes (CNT in a ceramic matrix – Fe, NTC-13%ZrO2 – (87-xAl2O3-xFe, (x = 1.9, 4.6 y 6.4%, were obtained using a combustion synthesis urea-nitrate, calcination treatment and chemical vapor deposition (CCVD in H2-CH4 atmosphere. The effect of the addition of Fe ions on the ceramic matrix was studied and presented. The ceramic powder obtained was calcined at 1200 °C for 2 h to modify the phases present in the solid solution. Subsequently it was introduced in a H2-CH4 reducing atmosphere at 1000 °C in order to promote the formation of CNT in the matrix. Both, the solid solution obtained and the composite materials were characterized by X-ray diffraction (XRD and high resolution scanning electron microscopy (HRSEM. Carbon content and specific surface also were determined. The quality and quantity of CNT present in the nanocomposite powder were related to the concentration of Fe, which significantly modifies their carbon content and specific surface.Mediante una síntesis por combustión ureica-nitratos, calcinación y la aplicación de un tratamiento de deposición química catalítica de vapor (CCVD en una atmósfera H2-CH4, se obtuvieron polvos nanocomposites: nanotubos de carbono (NTC en una matriz cerámica –Fe, NTC-13%ZrO2 – (87-xAl2O3-xFe, (x = 1.9, 4.6 y 6.4 %. El efecto de la adición de iones Fe sobre la matriz cerámica es estudiado y presentado. El polvo cerámico obtenido es calcinado a 1200 °C durante 2 h para modificar las fases presentes del composite. Posteriormente es sometido a una atmósfera reductora H2-CH4 a 1000 °C con la finalidad de promover la formación de NTC in situ en la matriz. Tanto el composite obtenido, como el material nanocomposite fueron caracterizados por difracción de rayos X (DRX y microscopía electrónica de barrido de alta resolución (MEB. También se determinó el contenido de carbono y la superficie específica. Se observó que la calidad y cantidad de NTC presentes en los polvos

Common Exercise X, step 1 using Matlab Reference: A41-T3-NL-05-4

NARCIS (Netherlands)

Schijndel, van A.W.M.

2005-01-01

This document presents a preliminary solution to Common exercise x. The exercise is solved by writing a mfile in MatLab. Appendix A provides a table with the requested calculations results, with: Orient Orientation Pin calculated internal pressure err Pin error in calculated internal pressure G1

Soft X-ray observations of the supernova remnants HB 3 and 3C 58

Science.gov (United States)

Galas, C. M. F.; Tuohy, I. R.; Garmire, G. P.

1980-01-01

The HEAO 1 A-2 low energy detectors have discovered soft X-ray emission from a source positionally coincident with the supernova remnant HB 3. The flux in the energy range 0.3-2.2 keV is about 6 x 10 to the -11th ergs per sq cm s. The spectral data are fitted to a hydrogen thermal bremsstrahlung model, and the physical parameters of the supernova remnant are estimated. The age derived is about 21,000 years, and the initial blast energy is about 3.1 x 10 to the 50th ergs. Upper limits to the soft X-ray flux and the luminosity of the supernova remnant 3 C 58 are also derived.

Ni(3)Si(Al)/a-SiO(x) core-shell nanoparticles: characterization, shell formation, and stability.

Science.gov (United States)

Pigozzi, G; Mukherji, D; Gilles, R; Barbier, B; Kostorz, G

2006-08-28

We have used an electrochemical selective phase dissolution method to extract nanoprecipitates of the Ni(3)Si-type intermetallic phase from two-phase Ni-Si and Ni-Si-Al alloys by dissolving the matrix phase. The extracted nanoparticles are characterized by transmission electron microscopy, energy-dispersive x-ray spectrometry, x-ray powder diffraction, and electron powder diffraction. It is found that the Ni(3)Si-type nanoparticles have a core-shell structure. The core maintains the size, the shape, and the crystal structure of the precipitates that existed in the bulk alloys, while the shell is an amorphous phase, containing only Si and O (SiO(x)). The shell forms around the precipitates during the extraction process. After annealing the nanoparticles in nitrogen at 700 °C, the tridymite phase recrystallizes within the shell, which remains partially amorphous. In contrast, on annealing in air at 1000 °C, no changes in the composition or the structure of the nanoparticles occur. It is suggested that the shell forms after dealloying of the matrix phase, where Si atoms, the main constituents of the shell, migrate to the surface of the precipitates.

The 3-loop non-singlet heavy flavor contributions and anomalous dimensions for the structure function F{sub 2}(x,Q{sup 2}) and transversity

Energy Technology Data Exchange (ETDEWEB)

Ablinger, J. [Research Institute for Symbolic Computation (RISC), Johannes Kepler University, Altenbergerstraße 69, A-4040 Linz (Austria); Behring, A.; Blümlein, J.; De Freitas, A. [Deutsches Elektronen-Synchrotron, DESY, Platanenallee 6, D-15738 Zeuthen (Germany); Hasselhuhn, A. [Research Institute for Symbolic Computation (RISC), Johannes Kepler University, Altenbergerstraße 69, A-4040 Linz (Austria); Manteuffel, A. von [PRISMA Cluster of Excellence and Institute of Physics, J. Gutenberg University, D-55099 Mainz (Germany); Round, M. [Research Institute for Symbolic Computation (RISC), Johannes Kepler University, Altenbergerstraße 69, A-4040 Linz (Austria); Deutsches Elektronen-Synchrotron, DESY, Platanenallee 6, D-15738 Zeuthen (Germany); Schneider, C. [Research Institute for Symbolic Computation (RISC), Johannes Kepler University, Altenbergerstraße 69, A-4040 Linz (Austria); Wißbrock, F. [Research Institute for Symbolic Computation (RISC), Johannes Kepler University, Altenbergerstraße 69, A-4040 Linz (Austria); Deutsches Elektronen-Synchrotron, DESY, Platanenallee 6, D-15738 Zeuthen (Germany)

2014-09-15

We calculate the massive flavor non-singlet Wilson coefficient for the heavy flavor contributions to the structure function F{sub 2}(x,Q{sup 2}) in the asymptotic region Q{sup 2}≫m{sup 2} and the associated operator matrix element A{sub qq,Q}{sup (3),NS}(N) to 3-loop order in Quantum Chromodynamics at general values of the Mellin variable N. This matrix element is associated with the vector current and axial vector current for the even and the odd moments N, respectively. We also calculate the corresponding operator matrix elements for transversity, compute the contributions to the 3-loop anomalous dimensions to O(N{sub F}) and compare to results in the literature. The 3-loop matching of the flavor non-singlet distribution in the variable flavor number scheme is derived. All results can be expressed in terms of nested harmonic sums in N space and harmonic polylogarithms in x-space. Numerical results are presented for the non-singlet charm quark contribution to F{sub 2}(x,Q{sup 2})

Superstring Theory on $AdS_{3} x G/H$ and Boundary N=3 Superconformal Symmetry

CERN Document Server

Argurio, R; Shomer, A; Argurio, Riccardo; Giveon, Amit; Shomer, Assaf

2000-01-01

Superstrings propagating on backgrounds of the form AdS_3 x G/H are studiedusing the coset CFT approach. We focus on seven dimensional cosets which have asemiclassical limit, and which give rise to N=3 superconformal symmetry in thedual CFT. This is realized for the two cases AdS_3 x SU(3)/U(1) and AdS_3 xSO(5)/SO(3), for which we present an explicit construction. We also providesufficient conditions on a CFT background to enable a similar construction, andcomment on the geometrical interpretation of our results.

Structural study of SiC(0 0 0 1)3x3 surface by surface X-ray diffraction

International Nuclear Information System (INIS)

Aoyama, T.; Akimoto, K.; Ichimiya, A.; Hisada, Y.; Mukainakano, S.; Emoto, T.; Tajiri, H.; Takahashi, T.; Sugiyama, H.; Zhang, X.; Kawata, H.

2003-01-01

Surface structure of 6H-SiC(0 0 0 1)3x3 reconstruction has been studied by grazing incidence X-ray diffraction with synchrotron radiation. We compared the Patterson map obtained from experimental structure factors with calculated Patterson maps estimated from the models that had been proposed. As the result, the calculated Patterson maps of Kulakov et al.'s [Surf. Sci. 346 (1996) 49] and Starke and coworkers' models [Phys. Rev. Lett. 80 (1998) 758; Phys. Rev. B 58 (1998) 10806; Surf. Rev. Lett. 6 (1999) 1129; Appl. Surf. Sci. 162-163 (2000) 9; Phys. Rev. B 62 (2000) 10335] are relatively in good agreement with experimental one. Therefore, we conclude that there is high possibility that either Kulakov et al.'s or Starke and coworkers' models are reasonable as the actual 3x3 structure

Affinity of hemoglobin for the cytoplasmic fragment of human erythrocyte membrane band 3. Equilibrium measurements at physiological pH using matrix-bound proteins: the effects of ionic strength, deoxygenation and of 2,3-diphosphoglycerate.

Science.gov (United States)

Chétrite, G; Cassoly, R

1985-10-05

The cytoplasmic fragment of band 3 protein isolated from the human erythrocyte membrane was linked to a CNBr-activated Sepharose matrix in an attempt to measure, in batch experiments, its equilibrium binding constant with oxy- and deoxyhemoglobin at physiological pH and ionic strength values and in the presence or the absence of 2,3-diphosphoglycerate. All the experiments were done at pH 7.2, and equilibrium constants were computed on the basis of one hemoglobin tetramer bound per monomer of fragment. In 10 mM-phosphate buffer, a dissociation constant KD = 2 X 10(-4)M was measured for oxyhemoglobin and was shown to increase to 8 X 10(-4)M in the presence of 50 mM-NaCl. Association could not be demonstrated at higher salt concentrations. Diphosphoglycerate-stripped deoxyhemoglobin was shown to associate more strongly with the cytoplasmic fragment of band 3. In 10 mM-bis-Tris (pH 7.2) and in the presence of 120 mM-NaCl, a dissociation constant KD = 4 X 10(-4)M was measured. Upon addition of increasing amounts of 2,3-diphosphoglycerate, the complex formed between deoxyhemoglobin and the cytoplasmic fragment of band 3 was dissociated. On the reasonable assumption that the hemoglobin binding site present on band 3 fragment was not modified upon linking the protein to the Sepharose matrix, the results indicated that diphosphoglycerate-stripped deoxyhemoglobin or partially liganded hemoglobin tetramers in the T state could bind band 3 inside the intact human red blood cell.

DFT analysis and FDTD simulation of CH3NH3PbI3-x Cl x mixed halide perovskite solar cells: role of halide mixing and light trapping technique

Science.gov (United States)

Saffari, Mohaddeseh; Mohebpour, Mohammad Ali; Rahimpour Soleimani, H.; Bagheri Tagani, Meysam

2017-10-01

Since perovskite solar cells have attracted a great deal of attention over the past few years, the enhancement of their optical absorption and current density are among the basic upcoming challenges. For this reason, first, we have studied the structural and optical properties of organic-inorganic hybrid halide perovskite CH3NH3PbI3 and the compounds doped by chlorine halogen CH3NH3PbI3-x Cl x in the cubic phase by using a density functional theory (DFT). Then, we model a single-junction perovskite solar cell based on a full solution to Maxwell’s equations, using a finite difference time domain (FDTD) technique, which helps us to investigate the light absorption efficiency and optical current density of the cell with CH3NH3PbI3-x Cl x (x  =  0, 1, 2, 3) as the active layer. The results suggest that increasing the amount of chlorine in CH3NH3PbI3-x Cl x compound leads to an increase in the bandgap energy, as well as a decrease in the lattice constants and optical properties, like the refractive index and extinction coefficient of the structure. Also, the results obtained by the simulation express that by taking advantage of the light trapping techniques of SiO2, a remarkable increase of light absorption will be achieved to the magnitude of 83.13%, which is noticeable.

Relationship between electrical and structural properties in Pr2/3+xTiO3±y

International Nuclear Information System (INIS)

Kirsanov, N.A.; Bazuev, G.V.

1987-01-01

Synthesis conditions results of X-ray diffraction investigations and electric properties of oxide titanium bronzes (OTB) of praseodymium Pr 2/3+x TiO 3±y in homogeneity region are presented. Change of crystal lattice symmetry in the region of existence of oxide titanium bronzes Pr 2/3+x TiO 3 ± y (O ≤ x ≤ 1/3) was revealed. Specific electrical resistance measurements enabled to conclude that d-electrons of Ti 3+ cations were characterized by collectivized behaviour, conditioned by formation of harrow, partially occupied π*-zone

Luminescent and scintillation properties of the Pr"3"+ doped single crystalline films of Lu_3Al_5_−_xGa_xO_1_2 garnet

International Nuclear Information System (INIS)

Gorbenko, V.; Zorenko, Yu; Zorenko, T.; Voznyak, T.; Paprocki, K.; Fabisiak, K.; Fedorov, A.; Bilski, P.; Twardak, A.; Zhusupkalieva, G.

2016-01-01

The Pr"3"+ d–f luminescence was investigated in the single crystalline films (SCF) of Lu_3Al_5_−_xGa_xO_1_2:Pr garnet solid solution at x = 1–3, grown by the liquid phase epitaxy (LPE) method from the melt-solution based on the PbO–B_2O_3 flux. The shape of CL spectra and decay kinetics of Pr"3"+ ions in Lu_3Al_5_−_xGa_xO_1_2 SCFs strongly depend on the total gallium concentration x and distribution of Ga"3"+ ions between the tetrahedral and octahedral position of the garnet host. The best scintillation properties of Lu_3Al_5_−_xGa_xO_1_2:Pr SCF are achieved at the nominal Ga content in melt-solution in the x = 2–2.5 range. - Highlights: • Single crystalline films of Lu_3Al_5_−_x Ga_xO_1_2:Pr garnet at x = 1–3 were grown by the LPE method. • Pr"3"+ emission spectra, light yield and decay time of films show strong dependence on Ga content. • The maximal light yield of Lu_3Al_5_−_x Ga_xO_1_2:Pr film is observed at Ga content x = 2.0–2.5.

Phenomenology of the SU(3)c x SU(3)L x U(1)X model with right-handed neutrinos

International Nuclear Information System (INIS)

Gutierrez, D.A.; Ponce, W.A.; Sanchez, L.A.

2006-01-01

A phenomenological analysis of the three-family model based on the local gauge group SU(3) c x SU(3) L x U(1) X with right-handed neutrinos is carried out. Instead of using the minimal scalar sector able to break the symmetry in a proper way, we introduce an alternative set of four Higgs scalar triplets, which combined with an anomaly-free discrete symmetry, produces a quark mass spectrum without hierarchies in the Yukawa coupling constants. We also embed the structure into a simple gauge group and show some conditions for achieving a low energy gauge coupling unification, avoiding possible conflict with proton decay bounds. By using experimental results from the CERN-LEP, SLAC linear collider, and atomic parity violation data, we update constraints on several parameters of the model. (orig.)

Heteroepitaxial growth of Ba1 - xSrxTiO3/YBa2Cu3O7 - x by plasma-enhanced metalorganic chemical vapor deposition

Science.gov (United States)

Chern, C. S.; Liang, S.; Shi, Z. Q.; Yoon, S.; Safari, A.; Lu, P.; Kear, B. H.; Goodreau, B. H.; Marks, T. J.; Hou, S. Y.

1994-06-01

Epitaxial Ba1-xSrxTiO3(BST)/YBa2Cu3O7-x heterostructures with superior electrical and dielectric properties have been fabricated by plasma-enhanced metalorganic chemical vapor deposition (PE-MOCVD). Data of x-ray diffraction and high resolution transmission electron microscopy showed that oriented Ba1-xSrxTiO3 layers were epitaxially deposited on epitaxial (001) YBa2Cu3O7-x layers. The leakage current density through the Ba1-xSrxTiO3 films was about 10-7 A/cm2 at 2 V (about 2×105 V/cm) operation. Moreover, the results of capacitance-temperature measurements showed that the PE-MOCVD Ba1-xSrxTiO3 films had Curie temperatures of about 30 °C and a peak dielectric constant of 600 at zero bias voltage. The Rutherford backscattering spectrometry and x-ray diffraction results showed that the BST film composition was controlled between Ba0.75Sr0.25TiO3 and Ba0.8Sr0.2TiO3. The structural and electrical properties of the Ba1-xSrxTiO3/YBa2Cu3O7-x heterostructure indicated that conductive oxide materials with close lattice to Ba1-xSrxTiO3 can be good candidates for the bottom electrode.

Effects of CsBr addition on the performance of CH3NH3PbI3-xClx-based solar cells

Science.gov (United States)

Ueoka, Naoki; Oku, Takeo; Ohishi, Yuya; Tanaka, Hiroki; Suzuki, Atsushi; Sakamoto, Hiroki; Yamada, Masahiro; Minami, Satoshi; Tsukada, Shinichiro

2018-01-01

Perovskite-type photovoltaic devices were prepared by a spin-coating method using a precursor solution of CH3NH3I and lead(II) chloride in N,N-dimethylformamide. Effects of cesium bromide (CsBr) addition on the photovoltaic properties and microstructures of the perovskite phase were investigated. The fill factor was increased by adding the CsBr to the CH3NH3PbI3-xClx precursor solution, which resulted in increase of the conversion efficiency. The crystallinity of the CH3NH3PbI3-xClx perovskite phase was also improved by adding the CsBr to the H3NH3PbI3-xClx precursor solution.

Bi[NC5H3(CO2)2](OH2)xF (x=1 and 2): New one-dimensional Bi-coordination materials—Reversible hydration and topotactic decomposition to α-Bi2O3

Science.gov (United States)

Jeon, Hye Rim; Lee, Dong Woo; Ok, Kang Min

2012-03-01

Two one-dimensional bismuth-coordination materials, Bi[NC5H3(CO2)2](OH2)xF (x=1 and 2), have been synthesized by hydrothermal reactions using Bi2O3, 2,6-NC5H3(CO2H)2, HF, and water at 180 °C. Structures of the two materials were determined by single-crystal X-ray diffraction. Although they have different crystal structures, both Bi-organic materials shared a common structural motif, a one-dimensional chain structure consisting of Bi3+ cations and pyridine dicarboxylate linkers. Detailed structural analyses include infrared spectroscopy, thermogravimetric analysis, and reversible hydration reactions for the coordinated water molecules were reported. Also, thermal decomposition of the rod-shaped Bi[NC5H3(CO2)2](OH2)F single crystals at 800 °C led to α-Bi2O3 that maintained the same morphology of the original crystals.

Study of Synergetic Effect of X2 and X3 EC Wave in KSTAR

Directory of Open Access Journals (Sweden)

Bae Y.S.

2015-01-01

Full Text Available An experimental study of the X-mode absorption at the second and the third harmonic frequencies has been performed in KSTAR tokamak. The X2 EC frequency is 110 GHz and the X3 EC frequency is 170 GHz at the nominal KSTAR operating toroidal magnetic field. From the 1-D model of the synergetic effect, the X3 cold resonance should lie at low field side with the X2 cold resonance at the high field side to meet the condition which both X2 and X3 EC waves interact with the same resonant electron at the same radial position. However, 170 GHz X3 cold resonance lies at the high field side with distance of 54 mm from the X2 cold resonance position in KSTAR. This paper presents the study of the synergetic effect of X3 absorption by the X2 ECCD with a scheme of two beam target positions at the same flux surface by scanning the poloidal and toroidal beam injection angles to enhance X3 absorption even in the low temperature plasma in KSTAR. For this study, the3D relativistic ray/tracing and Fokker-Planck codes C3PO/LUKE is used for the quantitative prediction of its synergetic effect. The C3PO/LUKE codes are appropriate for X2 and X3 synergy calculations as the distribution function can be calculated with either one or both waves affecting the absorption rate of each other. This paper also introduces the future ECH system upgrade plan.

Characterization and crystal defects of the new YBa2Cu3O7-x superconductor

International Nuclear Information System (INIS)

Boulesteix, C.; Ben Salem, M.; Mokrani, R.

1987-01-01

YBa 2 Cu 3 O 7-x superconductors from different origins have been studied by electron microscopy and X ray emission. This material has an easy clevage plane parallel to (001) making its observation easy. It has been shown that the preparation reaction was not complete for some superconducting materials. YBa 2 Cu 3 O 7-x crystals can be twinned (mechanical twins, ferroelastic material) but they are generally not, or have few twins. Another oxide has been encountered in epitaxial growth on YBa 2 Cu 3 O 7-x . A superlattice perpendicular to the common c axis has been observed probably due to a regular stacking of the both oxides [fr

Tensile properties of in situ synthesized titanium matrix composites reinforced by TiB and Nd2O3 at elevated temperature

International Nuclear Information System (INIS)

Geng Ke; Lu Weijie; Zhang Di; Sakata, Taokao; Mori, Hirotaro

2003-01-01

Titanium matrix composites reinforced with TiB and Nd 2 O 3 were prepared by a non-consumable arc-melting technology. X-ray diffraction (XRD) was used to identify the phases in the composites. Microstructures of the composites were observed by means of optical microscope (OM). There are three phases: TiB, Nd 2 O 3 and titanium matrix. TiB grows in needle shape, whereas Nd 2 O 3 grows in lath shape. Tensile properties of the composites were tested at 773, 823 and 873 K. Both the fracture surfaces and longitudinal sections of the fractured tensile specimens were comprehensively examined by scanning electron microscope (SEM). The fracture mode and fracture process at different temperatures were analyzed and explained. It shows that the tensile strength of the composites has a significant improvement at elevated temperatures compared to titanium matrix. The ductility of the composites improves with the content of neodymium and the test temperatures. The titanium composite exhibits different fracture modes at different test temperatures

Matrix inversion tomosynthesis improvements in longitudinal x-ray slice imaging

International Nuclear Information System (INIS)

Dobbines, J.T. III.

1990-01-01

This patent describes a tomosynthesis apparatus. It comprises: an x-ray tomography machine for producing a plurality of x-ray projection images of a subject including an x-ray source, and detection means; and processing means, connected to receive the plurality of projection images, for: shifting and reconstructing the projection x-ray images to obtain a tomosynthesis matrix of images T; acquiring a blurring matrix F having components which represent out-of-focus and in-focus components of the matrix T; obtaining a matrix P representing only in-focus components of the imaged subject by solving a matrix equation including the matrix T and the matrix F; correcting the matrix P for low spatial frequency components; and displaying images indicative of contents of the matrix P

Weak mixing angle and the SU(3)CxSU(3) model on M4xS1/(Z2xZ'2)

International Nuclear Information System (INIS)

Li Tianjun; Wei Liao

2002-05-01

We show that the desirable weak mixing angle sin 2 θ W =0.2312 at m Z scale can be generated naturally in the SU(3) C xSU(3) model on M 4 xS 1 /(Z 2 x Z 2 ') where the gauge symmetry SU(3) is broken down to SU(2) L xU(1) Y by orbifold projection. For a supersymmetric model with a TeV scale extra dimension, the SU(3) unification scale is about hundreds of TeVs at which the gauge couplings for SU(3) C and SU(3) can also be equal in the mean time. For the non-supersymmetric model, SU(2) L xU(1) Y are unified at order of 10 TeV. These models may serve as good candidates for physics beyond the SM or MSSM. (author)

Effect of sintering temperature on microstructure and transport properties of Li3xLa2/3-xTiO3 with different lithium contents

International Nuclear Information System (INIS)

Geng Hongxia; Lan Jinle; Mei Ao; Lin Yuanhua; Nan, C.W.

2011-01-01

Li 3x La 2/3-x TiO 3 (LLTO) powder with different lithium contents (nominal 3x = 0.03-0.75) was synthesized via a simple sol-gel route and then calcination of gel-derived precursor at 900 o C which was much below the calcination temperature required for synthesizing the LLTO powder via solid state reaction route. The LLTO powder of sub-micron sized particles, derived from such sol-gel method, showed almost no aggregation. Starting from the sol-gel-derived powder, the LLTO ceramics with different lithium contents were prepared at different sintering temperatures of 1250 and 1350 o C. It demonstrated that our sol-gel route is quite simple and convenient compared to the previous sol-gel method and requires lower temperature for the LLTO. Our results also illustrated that lithium content significantly affects the structure and ionic conductivity of the LLTO ceramics. The dependence of the ionic conductivity on the lithium content, lattice structure, microstructure and sintering temperature was investigated systematically.

Designing new lithium-excess cathode materials from percolation theory: nanohighways in Li(x)Ni(2-4x/3)Sb(x/3)O2.

Science.gov (United States)

Twu, Nancy; Li, Xin; Urban, Alexander; Balasubramanian, Mahalingam; Lee, Jinhyuk; Liu, Lei; Ceder, Gerbrand

2015-01-14

Increasing lithium content is shown to be a successful strategy for designing new cathode materials. In layered Li(x)Ni(2-4x/3)Sb(x/3)O2 (x = 1.00-1.15), lithium excess improves both discharge capacity and capacity retention at 1C. Structural studies reveal a complex nanostructure pattern of Li-Sb and Ni-Sb ordering where the interface between these domains forms the correct local configuration for good lithium mobility. The <1 nm Li-Sb stripe domains and their interfaces thereby effectively act as nanohighways for lithium diffusion.

Generators, Relations and Symmetries in Pairs of 3x3 Unimodular Matrices

OpenAIRE

Lawton, Sean

2006-01-01

Denote the free group on two letters by F2 and the SL(3,C)-representation variety of F2 by R = Hom(F2, SL(3,C)). There is a SL(3,C)-action on the coordinate ring of R, and the geometric points of the subring of invariants is an affine variety X. We determine explicit minimal generators and defining relations for the subring of invariants and show X is a degree 6 hyper-surface in C9 mapping onto C8. Our choice of generators exhibit Out(F2) symmetries which allow for a succinct expression of th...

Epitaxial growth and properties of YBa2Cu3O(x)-Pb(Zr(0.6)Ti(0.4))O3-YBa2Cu3O(x) trilayer structure by laser ablation

Science.gov (United States)

Boikov, Iu. A.; Esaian, S. K.; Ivanov, Z. G.; Brorsson, G.; Claeson, T.; Lee, J.; Safari, A.

1992-08-01

YBa2Cu3O(x)Pb(Zr(0.6)Ti(0.4))O3-YBa2Cu3O(x) multilayer structure has been grown on SrTiO3 and Al2O3 substrates using laser ablation. The deposition conditions for the growth of trilayers and their properties are studied in this investigation. Scanning electron microscope images and X-ray diffraction analyses indicate that all the constituent films in the trilayer grow epitaxially on SrTiO3 and were highly oriented on Al2O3. Transport measurements on these multilayers show that top YBa2Cu3O(x) films have good superconducting properties.

Effects of Tb{sup 3+} concentration on the La{sub 2}Sr{sub 3}(BO{sub 3}){sub 4}: X% Tb{sup 3+} polycrystalline nanophosphor

Energy Technology Data Exchange (ETDEWEB)

Mlotswa, D.V. [Physics Department, University of the Free State, Private Bag x13, Phuthaditjhaba 9866 (South Africa); Madihlaba, R.M. [Chemistry Department, University of the Western Cape, Private Bag x17, Bellville 7535 (South Africa); Koao, L.F. [Physics Department, University of the Free State, Private Bag x13, Phuthaditjhaba 9866 (South Africa); Onani, M.O., E-mail: monani@uwc.ac.za [Chemistry Department, University of the Western Cape, Private Bag x17, Bellville 7535 (South Africa); Dejene, F.B. [Physics Department, University of the Free State, Private Bag x13, Phuthaditjhaba 9866 (South Africa)

2016-01-01

A new green phosphor, La{sub 2}Sr{sub 3}(BO{sub 3}){sub 4}): x% Tb{sup 3+} was fabricated by solution-combustion method using urea as a fuel and ammonium nitrate as an oxidizer. The phosphor was characterised using Fourier transform infrared spectroscopy (FTIR), Thermogravimetric analysis (TGA), Differential scanning calorimetry (DSC), Energy dispersive spectroscopy, X-ray diffraction (XRD), scanning electron microscopy (SEM) and photoluminescence spectroscopy (PL. The results exhibit that La{sub 2}Sr{sub 3}(BO{sub 3}){sub 4}): x% Tb{sup 3+} phosphor has the strongest excitation at 209 nm with a full-width at half-maximum (FWHM) of 20 nm, and can emit bright green light at 545 nm under 209 nm excitation. The optimum concentration for Tb{sup 3+} in La{sub 2}Sr{sub 3}(BO{sub 3}){sub 4}): x% Tb{sup 3+} is 0.033 mol%. The prominent green luminescence was due to the {sup 5}D{sub 4}–{sup 7}F{sub 5} transition of Tb{sup 3+} ion. Herein, the green phosphors are promising good candidates employed in tri-color lamps.

Synthesis and Characterization of Perovskite Type La1-xSrxAlO3-sigma(0<=X<=0.3) by Co-Precipitation Method

International Nuclear Information System (INIS)

Mahmoud, O.; Abderezak, G.

2015-01-01

This work shows the electrochemical activity of O/sub 2/ evolution reaction in KOH of perovskite type- aluminate oxide (La/sub 1-x/Sr/sub x/AlO/sub 3-sigma/ with x = 0, 0.1, 0.2, 0.3). La/sub 1-x/Sr/sub x/AlO/sub 3-sigma/ (0<x<0.3) was prepared by co-precipitation method. The white precipitates were then washed in distilled water by centrifugation, and calcined at 1000/degree C/ for 6h, the pure phase was characterized by X-ray diffraction (XRD), thermal gravimetric analysis and differential thermal (TG/DSC), Fourier transform infrared spectroscopy (FTIR), specific surface area (BET). The MEB micrographs are shown of the spherical grains and uniform agglomeration of the grains. The oxide powders were used as the films to form a support on Ni/oxides. Oxygen evolution on each oxide catalyst was signed in the cyclic voltammetry with +- 15 V range and the electrochemical impedance in the equivalent of 100 kHz. The results point out the electrode activity and stability of the x = 0.3 composition. (author)

Efficient and stable CH3NH3PbI3-x(SCN)x planar perovskite solar cells fabricated in ambient air with low-temperature process

Science.gov (United States)

Zhang, Zongbao; Zhou, Yang; Cai, Yangyang; Liu, Hui; Qin, Qiqi; Lu, Xubing; Gao, Xingsen; Shui, Lingling; Wu, Sujuan; Liu, Jun-Ming

2018-02-01

Planar perovskite solar cells (PSCs) based on CH3NH3PbI3-x(SCN)x (SCN: thiocyanate) active layer and low-temperature processed TiO2 films are fabricated by a sequential two-step method in ambient air. Here, alkali thiocyanates (NaSCN, KSCN) are added into Pb(SCN)2 precursor to improve the microstructure of CH3NH3PbI3-x(SCN)x perovskite layers and performance of the as-prepared PSCs. At the optimum concentrations of alkali thiocyanates as additives, the as-prepared NaSCN-modified and KSCN-modified PSCs demonstrate the efficiencies of 16.59% and 15.63% respectively, being much higher than 12.73% of the reference PSCs without additives. This improvement is primarily ascribed to the enhanced electron transport, reduced recombination rates and much improved microstructures with large grain size and low defect density at grain boundaries. Importantly, it is revealed that the modified PSCs at the optimized concentrations of alkali thiocyanates additives exhibit remarkably improved stability than the reference PSCs against humid circumstance, and a continuous exposure to humid air without encapsulation over 45 days only records about 5% degradation of the efficiency. These findings provide a facile approach to fabricate efficient and stable PSCs by low processing temperature in ambient air, both of which are highly preferred for future practical applications of PSCs.

Properties of Y Ba2 Cu3 O7-x-Ag prepared by the citrate technique

International Nuclear Information System (INIS)

Fonseca, Fabio Coral

1996-01-01

Y Ba 2 Cu 3 O 7-x (Y123) ceramic superconductor and YBa 2 Cu 3 O 7-x- Ag composite superconductors have been prepared by the citrate technique. Microstructural analysis has been done by X-ray diffractometry and optical ceramography. The superconducting behavior has been studied by 4 probe dc electrical resistivity in the 77 K - 140 K temperature range. Silver percolation in the ceramic matrix was studied by electrical resistivity measurements at room temperature; the percolation threshold was found to be approximately 25 vol. % (35.5 wt. %) Ag. Specimens with silver addition showed improvement in the flexural strength of the Y123 compound. The main results show that the critical temperatures does not depend on the silver content in the composite specimens, the normal state electrical behavior of the superconductor is affected by silver addition and approximately 3 wt. % (1.8 vol. %) Ag doping yields and optimized composite superconductor from the electrical, mechanical and microstructural pont of view, with platelet-like grain shapes. (author)

Properties of copper matrix reinforced with nano- and micro-sized Al2O3 particles

International Nuclear Information System (INIS)

Rajkovic, Viseslava; Bozic, Dusan; Jovanovic, Milan T.

2008-01-01

The mixture of electrolytic copper powder with 5 wt.% of commercial Al 2 O 3 powder (average particle size: 15 and 0.75 μm, respectively) and the inert gas atomized prealloyed copper powder (average particle size: 30 μm) containing 2.5 wt.% aluminum were separately milled in air up to 20 h in the planetary ball mill. During milling aluminum in the prealloyed copper powders was oxidized in situ by internal oxidation with oxygen from the air forming very fine nano-sized Al 2 O 3 particles. The internal oxidation of 2.5 wt.% aluminum generated 4.7 wt.% of Al 2 O 3 in the copper matrix. Powders and compacts were characterized by light and scanning electron microscopy (SEM), electron probe microanalysis (EPMA) and X-ray diffraction analysis. Microhardness and electrical conductivity were also included in measurements. The microhardness of Cu-2.5 wt.% Al compacts was 3.6 times higher than that of compacts processed from electrolytic copper powder. This increase in microhardness is a consequence of a fine dispersion of Al 2 O 3 particles and refined grain structure. The average values of electrical conductivity of compacts processed from Cu-5 wt.% Al 2 O 3 and Cu-2.5 wt.% Al powders previously milled for 20 h and were 88% and 70% IACS, respectively, which is a rather significant increase if compared with values of 60% and 23% IACS of compacts processed from as-received and non-milled powders. The microhardness of 20-h milled compacts decreases with the heat treatment at 800 deg. C. Due to the effect of nano-sized Al 2 O 3 particles Cu-2.5 wt.% Al compacts show lower decrease in microhardness. The results are discussed in terms of the effect of Al 2 O 3 particle size and fine grain structure on the reinforcing of the copper matrix

Studies on the Ln/sub 2/O/sub 3/ (Ln: rare-earth elements)-SrO-V/sub 2/O/sub 3/ system, 2. Some physical properties for Ln sub(1-x)Sr sub(x)VO sub(3-0. 1x) and SrO. Ln sub(1-x)Sr sub(x)VO sub(3-0. 1x) (Ln: Nd or Eu)

Energy Technology Data Exchange (ETDEWEB)

Shin-ike, T [Osaka Dental Coll., Hirakata (Japan); Adachi, G; Shiokawa, J

1981-01-01

Electrical and magnetic properties of the perovskite type solid solutions, Ln sub(1-x)Sr sub(x)VO sub(3-0.1x) (Ln: Nd or Eu), and the K/sub 2/NiF/sub 4/ type solid solutions, SrO.Ln sub(1-x)Sr sub(x)VO sub(3-0.1x) (Ln: Nd or Eu), were studied in the temperature range 77 - 300 K. The electrical conductivity increased with x for the perovskite type solid solutions and the reverse behavior was observed for the K/sub 2/NiF/sub 4/ type compounds. All the solid solutions examined exhibited a metal-insulator transition at some values of x. Both Nd sub(1-x)Sr sub(x)VO sub(3-0.1x) and Eu sub(1-x)Sr sub(x)VO sub(3-0.1x) were antiferromagnets having a weak ferromagnetism at a low value of x at a low temperature. The K/sub 2/NiF/sub 4/ type solid solutions revealed a weak ferromagnetism at a high value of x at a low temperature.

A Multiwavelength Study of Cygnus X-3

Science.gov (United States)

McCollough, M. L; Robinson, C. R.; Zhang, S. N.; Paciesas, W. S.; Harmon, B. A.; Hjellming, R. M.; Rupen, M.; Waltman, E. B.; Foster, R. S.; Ghigo, F. D.

1997-01-01

We present a global comparison of long term observations of the hard X-ray (20-100 keV), soft X-ray (1.5-12 keV), infrared (1-2 micron) and radio (2.25, 8.3 and 15 GHz) bands for the unusual X-ray binary Cygnus X-3. Data were obtained in the hard X-ray band from CGRO/BATSE, in the soft X-ray band from Rossi Xray Timing Explorer (RXTE)/ASM, in the radio band from the Green Bank Interferometer and Ryle Telescope and in the infrared band from various ground based observatories. Radio flares, quenched radio states and quiescent radio emission can all be associated with changes in the hard and soft X-ray intensity. The injection of plasma into the radio jet is directly related to changes in the hard and soft X-ray emission. The infrared observations are examined in the context of these findings.

Synthesis and performance of Li{sub 3}(V{sub 1-x}Mg{sub x}){sub 2}(PO{sub 4}){sub 3} cathode materials

Energy Technology Data Exchange (ETDEWEB)

Dai, Changsong; Chen, Zhenyu; Jin, Haizu; Hu, Xinguo [School of Chemical Engineering and Technology, Harbin Institute of Technology, Harbin 150001 (China)

2010-09-01

In order to search for cathode materials with better performance, Li{sub 3}(V{sub 1-x}Mg{sub x}){sub 2}(PO{sub 4}){sub 3} (0, 0.04, 0.07, 0.10 and 0.13) is prepared via a carbothermal reduction (CTR) process with LiOH.H{sub 2}O, V{sub 2}O{sub 5}, Mg(CH{sub 3}COO){sub 2}.4H{sub 2}O, NH{sub 4}H{sub 2}PO{sub 4}, and sucrose as raw materials and investigated by X-ray diffraction (XRD), scanning electron microscopic (SEM) and electrochemical impedance spectrum (EIS). XRD shows that Li{sub 3}(V{sub 1-x}Mg{sub x}){sub 2}(PO{sub 4}){sub 3} (x = 0.04, 0.07, 0.10 and 0.13) has the same monoclinic structure as undoped Li{sub 3}V{sub 2}(PO{sub 4}){sub 3} while the particle size of Li{sub 3}(V{sub 1-x}Mg{sub x}){sub 2}(PO{sub 4}){sub 3} is smaller than that of Li{sub 3}V{sub 2}(PO{sub 4}){sub 3} according to SEM images. EIS reveals that the charge transfer resistance of as-prepared materials is reduced and its reversibility is enhanced proved by the cyclic votammograms. The Mg{sup 2+}-doped Li{sub 3}V{sub 2}(PO{sub 4}){sub 3} has a better high rate discharge performance. At a discharge rate of 20 C, the discharge capacity of Li{sub 3}(V{sub 0.9}Mg{sub 0.1}){sub 2}(PO{sub 4}){sub 3} is 107 mAh g{sup -1} and the capacity retention is 98% after 80 cycles. Li{sub 3}(V{sub 0.9}Mg{sub 0.1}){sub 2}(PO{sub 4}){sub 3}//graphite full cells (085580-type) have good discharge performance and the modified cathode material has very good compatibility with graphite. (author)

3,4-Methylenedioxymethamphetamine (MDMA, ecstasy) disrupts blood-brain barrier integrity through a mechanism involving P2X7 receptors.

Science.gov (United States)

Rubio-Araiz, Ana; Perez-Hernandez, Mercedes; Urrutia, Andrés; Porcu, Francesca; Borcel, Erika; Gutierrez-Lopez, Maria Dolores; O'Shea, Esther; Colado, Maria Isabel

2014-08-01

The recreational drug 3,4-methylenedioxymethamphetamine (MDMA; 'ecstasy') produces a neuro-inflammatory response in rats characterized by an increase in microglial activation and IL-1β levels. The integrity of the blood-brain barrier (BBB) is important in preserving the homeostasis of the brain and has been shown to be affected by neuro-inflammatory processes. We aimed to study the effect of a single dose of MDMA on the activity of metalloproteinases (MMPs), expression of extracellular matrix proteins, BBB leakage and the role of the ionotropic purinergic receptor P2X7 (P2X7R) in the changes induced by the drug. Adult male Dark Agouti rats were treated with MDMA (10 mg/kg, i.p.) and killed at several time-points in order to evaluate MMP-9 and MMP-3 activity in the hippocampus and laminin and collagen-IV expression and IgG extravasation in the dentate gyrus. Microglial activation, P2X7R expression and localization were also determined in the dentate gyrus. Separate groups were treated with MDMA and the P2X7R antagonists Brilliant Blue G (BBG; 50 mg/kg, i.p.) or A-438079 (30 mg/kg, i.p.). MDMA increased MMP-3 and MMP-9 activity, reduced laminin and collagen-IV expression and increased IgG immunoreactivity. In addition, MDMA increased microglial activation and P2X7R immunoreactivity in these cells. BBG suppressed the increase in MMP-9 and MMP-3 activity, prevented basal lamina degradation and IgG extravasation into the brain parenchyma. A-438079 also prevented the MDMA-induced reduction in laminin and collagen-IV immunoreactivity. These results indicate that MDMA alters BBB permeability through an early P2X7R-mediated event, which in turn leads to enhancement of MMP-9 and MMP-3 activity and degradation of extracellular matrix.

Preparation and physical properties of (PVA0.7(NaBr0.3(H3PO4xM solid acid membrane for phosphoric acid – Fuel cells

Directory of Open Access Journals (Sweden)

F. Ahmad

2013-03-01

Full Text Available A solid acid membranes based on poly (vinyl alcohol (PVA, sodium bromide (NaBr and phosphoric acid (H3PO4 were prepared by a solution casting method. The morphological, IR, electrical and optical properties of the (PVA0.7(NaBr0.3(H3PO4xM solid acid membranes where x = 0.00, 0.85, 1.7, 3.4, 5.1 M were investigated. The variation of film morphology was examined by scanning electron microscopy (SEM studies. FTIR spectroscopy has been used to characterize the structure of polymer and confirms the complexation of phosphoric acid with host polymeric matrix. The temperature dependent nature of ionic conductivity and the impedance of the polymer electrolytes were determined along with the associated activation energy. The ionic conductivity at room temperature was found to be strongly depends on the H3PO4 concentration which it has been achieved to be of the order 4.3 × 10−3 S/cm at ambient temperature. Optical measurements showed a decrease in optical band gap and an increase in band tail width with the increase of phosphoric acid. The data shows that the (PVA0.7(NaBr0.3(H3PO4xM solid acid membrane is promising for intermediate temperature phosphoric acid fuel cell applications.

Study of the CdX-B2X3-X (X=S, Se), CdTe-B-Te systems

International Nuclear Information System (INIS)

Odin, I.N.; Grin'ko, V.V.; Safronov, E.V.; Kozlovskij, V.F.

2001-01-01

Liquidus surfaces of the CdX-B 2 X 3 -X (X=S, Se), CdTe-B-Te systems are plotted for the first time. It is shown that in equilibrium solid solutions on the basis of ternary Cd 2 B 2 X 5 compounds and binary B 2 X 3 , CdX, BS 2 compounds take part with liquid phases. p gen -T and T-x projects of p-T-x phase diagram of B-S (59-100 at. % S), B-Se (59-100 at. % Se), B-Te systems are plotted . B 2 X 3 , BS 2 compounds are formed in that regions of compositions of B-X systems . In the B-Te system compounds are not formed. Ternary compounds are not formed in the CdTe-B-Te system [ru

X-ray absorption investigation of the valence state and electronic structure of La1−xCaxCoO3−δ in comparison with La1−xSrxCoO3−δ and La1−xSrxFeO3−δ

International Nuclear Information System (INIS)

Haas, O.; Ludwig, Chr.; Bergmann, U.; Singh, R.N.; Braun, A.; Graule, T.

2011-01-01

3d metal K-shell X-ray absorption spectra of perovskites with the composition La 1−x Ca x CoO 3−δ (x=0, 0.2, 0.4, 0.5, 0.6, 0.8), La 1−x Sr x CoO 3−δ (x=0, 0.1, 0.2, 0.3, 0.4, 0.5) and La 1−x Sr x FeO 3−δ (x=0, 0.2, 0.4, 0.5, 0.6, 0.8) are compared on the basis of pre-edges, white line features and extended fine structures. The measurements were performed at 300 K and for La 1−x Ca x CoO 3−δ also at temperatures as low as 10–20 K. Going to low-temperature the measurements indicate an increase in t 2g ⁎ and a decrease in e g ⁎ orbital occupancy, which is most accentuated in the LaCoO 3 sample. Virtually no Co K-edge shift was observed for the La 1−x Ca x CoO 3−δ and La 1−x Sr x CoO 3−δ compounds and the Co–O distances are also not significantly reduced when La 3+ is partially substituted by Ca 2+ or Sr 2+ . From the pre-edge features of these perovskites we are tended to conclude that the t 2g ⁎ orbitals are less, and the e g ⁎ orbitals are more occupied with increasing x in the Ca and Sr substituted compounds, whereas the total d-electron density is not changing. These results indicate that cobalt prefers a valence state of 3 + in these Co perovskites. This could also be confirmed with iodometric titrations. The Fe perovskites behave differently. In contrast to the Co perovskites, for La 1−x Sr x FeO 3−δ perovskites the Fe K-edge is shifted, the pre-edge features intensity is increasing and the Fe–O bond length is decreasing with increasing x. The valence states of the iron in the La 1−x Sr x FeO 3−δ perovskites in fact increase as much as x increases. - Graphical abstract: Co K and Fe K pre-edge of La 1−x Ca x CoO 3−δ and La 1−x Sr x FeO 3−δ perovskites one of the evidences in favor of δ=x/2 for the Co-perovskites and δ=0 for the Fe-perovskites. Highlights: ► XAS a valuable tool to evaluate the valence states of Co and Fe perovskites. ► For La 1−x Ca x CoO 3−δ and La 1−x Sr x CoO 3�

Effect of silver doping on infrared reflectance and Tc of superconducting GdBa2Cu(1 - x)3Ag3xO7

International Nuclear Information System (INIS)

Memon, A.; Khan, M.N.; Al-Dallal, S.; Tanner, D.B.; Porter, C.D.

1990-01-01

This paper reports on infrared reflectance of GdBa 2 Cu(1 - x) 3 Ag 3x O 7 ceramic superconductor with the composition of x = 0.025 and 0.05 performed in the frequency range of 100--5000 cm -1 . All the infrared active phonon modes allowed by the selection rules were observed in the reflection spectra of these compounds. The optical conductivity as calculated from K--K analysis further confirms the existence of these optical phonons. Besides the increase of the reflectivity in the silver doped samples, an extra phonon mode is observed, which is normally not seen at room temperature reflectance of GdBa 2 Cu 3 O 7 compounds. The four probe resistivity measurement show zero resistance at 88 K for x = 0, and 78 K for x = 0.025 in GdBa 2 Cu(1 - x) 3 Ag 3x O 7 compound

A giant radio flare from Cygnus X-3 with associated γ-ray emission

Science.gov (United States)

Corbel, S.; Dubus, G.; Tomsick, J. A.; Szostek, A.; Corbet, R. H. D.; Miller-Jones, J. C. A.; Richards, J. L.; Pooley, G.; Trushkin, S.; Dubois, R.; Hill, A. B.; Kerr, M.; Max-Moerbeck, W.; Readhead, A. C. S.; Bodaghee, A.; Tudose, V.; Parent, D.; Wilms, J.; Pottschmidt, K.

2012-04-01

With frequent flaring activity of its relativistic jets, Cygnus X-3 (Cyg X-3) is one of the most active microquasars and is the only Galactic black hole candidate with confirmed high-energy γ-ray emission, thanks to detections by Fermi Large Area Telescope (Fermi/LAT) and AGILE. In 2011, Cyg X-3 was observed to transit to a soft X-ray state, which is known to be associated with high-energy γ-ray emission. We present the results of a multiwavelength campaign covering a quenched state, when radio emission from Cyg X-3 is at its weakest and the X-ray spectrum is very soft. A giant (˜20 Jy) optically thin radio flare marks the end of the quenched state, accompanied by rising non-thermal hard X-rays. Fermi/LAT observations (E≥ 100 MeV) reveal renewed γ-ray activity associated with this giant radio flare, suggesting a common origin for all non-thermal components. In addition, current observations unambiguously show that the γ-ray emission is not exclusively related to the rare giant radio flares. A three-week period of γ-ray emission is also detected when Cyg X-3 was weakly flaring in radio, right before transition to the radio quenched state. No γ-rays are observed during the ˜1-month long quenched state, when the radio flux is weakest. Our results suggest transitions into and out of the ultrasoft X-ray (radio-quenched) state trigger γ-ray emission, implying a connection to the accretion process, and also that the γ-ray activity is related to the level of radio flux (and possibly shock formation), strengthening the connection to the relativistic jets.

Response matrix of a multisphere neutron spectrometer with an 3 He proportional counter

International Nuclear Information System (INIS)

Vega C, H.R.; Manzanares A, E.; Hernandez D, V.M.; Mercado S, G.A.

2005-01-01

The response matrix of a Bonner sphere spectrometer was calculated by use of the MCNP code. As thermal neutron counter, the spectrometer has a 3.2 cm-diameter 3 He-filled proportional counter which is located at the center of a set of polyethylene spheres. The response was calculated for 0, 3, 5, 6, 8, 10, 12, and 16 inches-diameter polyethylene spheres for neutrons whose energy goes from 10 -9 to 20 MeV. The response matrix was compared with a set of responses measured with several monoenergetic neutron sources. In this comparison the calculated matrix agrees with the experimental results. The matrix was also compared with the response matrix calculated for the PTB C spectrometer. Even though that calculation was carried out using a detailed model to describe the proportional counter; both matrices do agree, but small differences are observed in the bare case because of the difference in the model used during calculations. Other differences are in some spheres for 14.8 and 20 MeV neutrons, probably due to the differences in the cross sections used during both calculations. (Author) 28 refs., 1 tab., 6 figs

The development of a 3-d risk matrix for qualitative maintenance risk management

International Nuclear Information System (INIS)

Hsu, Pi-Lin; Lo, Chung-Kung

2009-01-01

The 3-D Risk Matrix is a web-based tool, developed by the Institute of Nuclear Energy research (INER), to assist plant personnel for qualitative assessment of operational risks inherent with scheduling of system/component maintenance and testing. This paper focuses on a software development for a three-dimensional risk matrix which serves as a sub-function embedded in the Maintenance Rule (MR) risk management tool used by the Taiwan's nuclear power plants. The color in any field of the matrix directly corresponds to the risk condition level of the related plant maintenance configuration. It also informs the operators via graphical interface of the remaining hours before reaching to the potentially more significant risk level. In the 3-D Risk Matrix, the risk levels can be quickly determined since the conditional Core Damage Frequency (CDF) and Large Early Release Frequency (LERF) for each expected and allowed out-of-service sub-systems or trains combination is pre-calculated by INERISKEN. The 3-D Risk Matrix will play an important role to enhance the MR risk management tool during the on-line maintenances in Taiwan's nuclear power plants

Structure-property relations in sputter deposited epitaxial (1-x)Pb(Mg1/3Nb2/3)O3- xPbTiO3 thin films

Science.gov (United States)

Frederick, Joshua C.

Lead-based ferroelectric materials are of significant technological importance for sensing and actuation due to their high piezoelectric performance (i.e., the ability to convert an electrical signal to mechanical displacement, and vice versa). Traditionally, bulk ceramic or single crystals materials have filled these roles; however, emerging technologies stand to benefit by incorporating thin films to achieve miniaturization while maintaining high efficiency and sensitivity. Currently, chemical systems that have been well characterized in bulk form (e.g. Pb(Mg1/3Nb2/3)O3- xPbTiO3, or PMN-xPT) require further study to optimize both the chemistry and structure for deployment in thin film devices. Furthermore, the effect of internal electric fields is more significant at the length scales of thin films, resulting in self biases that require compensation to reveal their intrinsic dielectric response. To this end, the structure-property relations of epitaxial PMN-xPT films sputter deposited on a variety of substrates were investigated. Attention was paid to how the structure (i.e., strain state, crystal structure, domain configuration, and defects) gave rise to the ferroelectric, dielectric, and piezoelectric response. Three-dimensional visualization of the dielectric response as a simultaneous function of electric field and temperature revealed the true phase transition of the films, which was found to correspond to the strain state and defect concentration. A lead-buffered anneal process was implemented to enhance the ferroelectric and dielectric response of the films without altering their stoichiometry. It was discovered that PMN- xPT films could be domain-engineered to exhibit a mixed domain state through chemistry and substrate choice. Such films exhibited a monoclinic distortion similar to that of the bulk compositions near the morphotropic phase boundary. Finally, it was revealed that the piezoelectric response could be greatly enhanced by declamping the film

Phonon dispersion relations in PrBa2Cu3O6+x (x approximate to 0.2)

DEFF Research Database (Denmark)

Gardiner, C.H.; Boothroyd, A.T.; Larsen, B.H.

2004-01-01

We report measurements of the phonon dispersion relations in nonsuperconducting, oxygen-deficient PrBa2Cu3O6+x (xapproximate to0.2) by inelastic neutron scattering. The data are compared with a model of the lattice dynamics based on a common interatomic potential. Good agreement is achieved for all...

3D pancreatic carcinoma spheroids induce a matrix-rich, chemoresistant phenotype offering a better model for drug testing

International Nuclear Information System (INIS)

Longati, Paola; Heuchel, Rainer L; Jia, Xiaohui; Eimer, Johannes; Wagman, Annika; Witt, Michael-Robin; Rehnmark, Stefan; Verbeke, Caroline; Toftgård, Rune; Löhr, Matthias

2013-01-01

Pancreatic ductal adenocarcinoma (PDAC) is the fourth most common cause of cancer related death. It is lethal in nearly all patients, due to an almost complete chemoresistance. Most if not all drugs that pass preclinical tests successfully, fail miserably in the patient. This raises the question whether traditional 2D cell culture is the correct tool for drug screening. The objective of this study is to develop a simple, high-throughput 3D model of human PDAC cell lines, and to explore mechanisms underlying the transition from 2D to 3D that might be responsible for chemoresistance. Several established human PDAC and a KPC mouse cell lines were tested, whereby Panc-1 was studied in more detail. 3D spheroid formation was facilitated with methylcellulose. Spheroids were studied morphologically, electron microscopically and by qRT-PCR for selected matrix genes, related factors and miRNA. Metabolic studies were performed, and a panel of novel drugs was tested against gemcitabine. Comparing 3D to 2D cell culture, matrix proteins were significantly increased as were lumican, SNED1, DARP32, and miR-146a. Cell metabolism in 3D was shifted towards glycolysis. All drugs tested were less effective in 3D, except for allicin, MT100 and AX, which demonstrated effect. We developed a high-throughput 3D cell culture drug screening system for pancreatic cancer, which displays a strongly increased chemoresistance. Features associated to the 3D cell model are increased expression of matrix proteins and miRNA as well as stromal markers such as PPP1R1B and SNED1. This is supporting the concept of cell adhesion mediated drug resistance

Neutron diffraction and magnetic study of the Nd0.7Pb0.3Mn1-xFexO3 (0=<x=<0.1) perovskites

International Nuclear Information System (INIS)

Blanco, J.J.; Insausti, M.; Gil de Muro, I.; Lezama, L.; Rojo, T.

2006-01-01

The effect of Fe doping on the ferromagnetic Nd 0.7 Pb 0.3 Mn 1-x Fe x O 3 (x=0, 0.025, 0.05, 0.075, 0.1) phases has been studied in order to analyze the double-exchange interaction. The structural and magnetic study has been carried out by neutron powder diffraction and susceptibility measurements between 1.7 and 300K. The substitution of Fe at the Mn site results in reductions in both the Curie temperature T c and the magnetic moment per Mn ion without appreciable differences in the crystal structures. All the compounds crystallize in Pnma space group. The thermal evolution of the lattice parameters of the Nd 0.7 Pb 0.3 Mn 1-x Fe x O 3 (x=0.025, 0.05, 0.075) compounds shows discontinuities in volume and lattice parameters close to the magnetic transition temperature. Increasing amounts of Fe 3+ reduces the double exchange interactions and no magnetic contribution for x=0.1 is observed. The magnetic structures of Nd 0.7 Pb 0.3 Mn 1-x Fe x O 3 (x=0, 0.025, 0.05, 0.075) compounds show that the Nd and Mn ions are ferromagnetically ordered

Mixed valent noble metal perovskites Ba/sub 3/B/sup 3 +/Pt/sub x/Ru/sub 2-x//sup 4. 5+/O/sub 9/

Energy Technology Data Exchange (ETDEWEB)

Moessner, B; Kemmler-Sack, S; Ehmann, A [Tuebingen Univ. (Germany, F.R.). Lehrstuhl fuer Anorganische Chemie 2

1982-04-01

In perovskites of type Ba/sub 3/B/sup 3 +/Pt/sub x/Ru/sub 2-x//sup 4.5+/O/sub 9/ the ruthenium can be substituted by platinum up to x = 1. The compounds crystallize in a 1:2 ordered hexagonal BaTiO/sub 3/ structure (sequence (hcc)/sub 2/) with face connected Pt/sub x/Ru/sub 2-x/O/sub 9/ double octahedra. Intensity calculations on powder data of Ba/sub 3/YPt/sub 1/2/Ru/sub 3/2/O/sub 9/ (space group P6/sub 3//mmc) gave a refined, intensity related R' value of 8.6%. The vibrational spectroscopic and catalytic properties are reported.

Thermodynamical study of boron doped CeX{sub 3} (X=Pd, Rh)

Energy Technology Data Exchange (ETDEWEB)

Sharma, Ramesh [Dept. of Physics, Mewar University, Chittorgarh Rajasthan-India (India); Dwivedi, Shalini; Sharma, Yamini, E-mail: sharma.yamini62@gmail.com [Theoretical Condensed Matter Physics Laboratory, Dept. of Physics, Feroze Gandhi College, Raebareli-229001 U.P (India)

2016-05-06

The structural, electronic, thermal, and optical properties of cubic non magnetic CeX{sub 3}(X=Pd, Rh) compounds which crystallize in the Au{sub 3}Cu structure have been studied using the projected augmented wave (PAW) method within the density functional theory (DFT) with generalized gradient approximation (GGA) for exchange correlation potential. In this paper we have calculated the band structure which are interpreted using the density of states. The optical properties such as extinction coefficients clearly illustrate the changes in CeX{sub 3} due to intercalation of boron. Lattice instability is observed in CePd{sub 3}B from the calculated dynamical properties.

Fabrication and characterization of Ba sub x Sr sub 1 sub - sub x TiO sub 3 /YBa sub 2 Cu sub 3 O sub x /SrTiO sub 3 structure

CERN Document Server

Choi, J; Park, S Y; Lee Jae Sik; No, K; Sung, T H; Park, Y

2002-01-01

Ba sub x Sr sub 1 sub - sub x TiO sub 3 (BST)/YBa sub 2 Cu sub 3 O sub x (YBCO)/SrTiO sub 3 (STO) structures were deposited, and the microstructure, orientation and electrical characteristics were investigated. (00l) oriented YBCO thin films were deposited on STO substrates using pulsed laser deposition, and (h00) oriented BST thin films were deposited on YBCO/STO substrates using electron cyclotron resonance (ECR) plasma assisted metal organic chemical vapor deposition (MOCVD). A new phase was formed at the interface between YBCO and BST films and was speculated to be (Ba sub x Y sub 1 sub - sub x)(Ti sub y Y sub 1 sub - sub y)O sub 3. Ba-rich BST films showed a higher dielectric loss than Sr-rich BST films did, which indicates that Sr-rich BST films are more suited for application to microwave devices. The dielectric loss of the films was reduced as temperature decreased, which may be due to the conductivity change of YBCO film and the formation of a conduction path rather than a dielectric property change ...

Calibration of the x-ray ring quadrupoles, BPMs, and orbit correctors using the measured orbit response matrix

International Nuclear Information System (INIS)

Safranek, J.; Lee, M.

1994-02-01

The quadrupole strengths, beam position monitor (BPM) gains, and orbit correction magnet strengths were adjusted in a computer model of the NSLS X-Ray ring in order to best fit the model orbit response matrix to the measured matrix. The model matrix was fit tot the 4320 data points in the measured matrix with an rms difference of only 2 to 3 microns, which is due primarily to noise in the BPM measurements. The strengths of the 56 individual quadrupoles in the X-Ray ring were determined to an accuracy of about 0.2%. The BPM and orbit corrector calibrations were also accurately determined. A through analysis of both random and systematic errors is included

Car-borne survey measurements with a 3x3` NaI detector

Energy Technology Data Exchange (ETDEWEB)

Larsen, E.; Ugletveit, F.; Floe, L.; Mikkelborg, O. [Norwegian Radiation Protection Authority, Oesteraas (Norway)

1997-12-31

The Norwegian Radiation Protection Authority (NRPA) took part in the international survey measurement exercise RESUME95 that was arranged in Finland in August 1995. NRPA performed measurements with a simple car-borne measuring system based on standard equipment, a 3x3` NaI detector, an MCA and a GPS connected to a portable PC. The results show substantial variations in dose rate inside areas of a few square kilometres. Spectrum analysis shows that a major part of these differences are caused by variations in deposition of {sup 137}Cs. Our results show that even standard 3x3` NaI detectors can be used for car based survey measurements in fall out situations and search for sources. The detection limits are higher than for larger detectors, but the main limiting factor seem to be the timing capabilities of the acquisition system. (au).

Car-borne survey measurements with a 3x3' NaI detector

International Nuclear Information System (INIS)

Larsen, E.; Ugletveit, F.; Floe, L.; Mikkelborg, O.

1997-01-01

The Norwegian Radiation Protection Authority (NRPA) took part in the international survey measurement exercise RESUME95 that was arranged in Finland in August 1995. NRPA performed measurements with a simple car-borne measuring system based on standard equipment, a 3x3' NaI detector, an MCA and a GPS connected to a portable PC. The results show substantial variations in dose rate inside areas of a few square kilometres. Spectrum analysis shows that a major part of these differences are caused by variations in deposition of 137 Cs. Our results show that even standard 3x3' NaI detectors can be used for car based survey measurements in fall out situations and search for sources. The detection limits are higher than for larger detectors, but the main limiting factor seem to be the timing capabilities of the acquisition system. (au)

Car-borne survey measurements with a 3x3` NaI detector

Energy Technology Data Exchange (ETDEWEB)

Larsen, E; Ugletveit, F; Floe, L; Mikkelborg, O [Norwegian Radiation Protection Authority, Oesteraas (Norway)

1998-12-31

The Norwegian Radiation Protection Authority (NRPA) took part in the international survey measurement exercise RESUME95 that was arranged in Finland in August 1995. NRPA performed measurements with a simple car-borne measuring system based on standard equipment, a 3x3` NaI detector, an MCA and a GPS connected to a portable PC. The results show substantial variations in dose rate inside areas of a few square kilometres. Spectrum analysis shows that a major part of these differences are caused by variations in deposition of {sup 137}Cs. Our results show that even standard 3x3` NaI detectors can be used for car based survey measurements in fall out situations and search for sources. The detection limits are higher than for larger detectors, but the main limiting factor seem to be the timing capabilities of the acquisition system. (au).

The WA105-3x1x1 m3 dual phase LAr-TPC demonstrator

CERN Document Server

Murphy, Sebastien

2016-11-15

The dual phase Liquid Argon Time Projection Chamber (LAr TPC) is the state-of-art technology for neutrino detection thanks to its superb 3D tracking and calorimetry performance. Its main feature is the charge amplification in gas argon which provides excellent signal-to-noise ratio. Electrons produced in the liquid argon are extracted in the gas phase. Here, a readout plane based on Large Electron Multiplier detectors provides amplification of the charges before its collection onto an anode with strip readout. The charge amplification enables constructing fully homoge- nous giant LAr-TPCs with tuneable gain, excellent charge imaging performance and increased sensitivity to low energy events. Following a staged approach the WA105 collaboration is con- structing a dual phase LAr-TPC with an active volume of 3x1x1m3 that will soon be tested with cosmic rays. Its construction and operation aims to test scalable solutions for the crucial aspects of this technology: ultra high argon purity in non-evacuable tank, la...

Rattling of Ba-atoms in Ba8ZnxGe43-5x/8([]3-3x/8)

International Nuclear Information System (INIS)

Melnychenko, N.; Grytsiv, A.; Rotter, M.; Rogl, P.; Devishvili, A.

2006-01-01

Full text: In order to improve the figure of merit of thermoelectric materials, one of the key parameters to be minimized is the lattice thermal conductivity. It is thus essential for the design of new thermoelectric materials to understand the lattice dynamics, especially the scattering mechanism of low energy phonons. The present paper describes formation, phase relations at subsolidus temperatures as well as at 800 o C, crystal chemistry and physical properties of a series of ternary clathrates as part of the solid solution, Ba 8 Zn x (Ge 43-5x/8[]3-3x/8 ), deriving from binary Ba 8 Ge 43 []3 with a solubility limit of 8 Zn per formula unit at 800 o C. Structural investigations in all cases confirm cubic primitive symmetry with a lattice parameter a ∼ 1.1 nm consistent with the space group type Pm-3n. Studies of transport coefficients evidence electrons as the majority charge carriers in the systems. Thermal conductivity exhibits a pronounced low temperature maximum, dominated by the lattice contribution, while at higher temperatures the electronic part gains weight. Inelastic neutron scattering experiments are used to study the phonon spectrum for Ba 8 Zn 8 Ge 38 . (author)

Matrix metalloproteinase-3 gene polymorphism in renal transplant patients with gingival overgrowth.

Science.gov (United States)

Drozdzik, A; Kurzawski, M; Lener, A; Kozak, M; Banach, J; Drozdzik, M

2010-02-01

Gingival enlargement frequently occurs in transplant patients receiving immunosuppressive drugs. It was hypothesized that gingival enlargement associated with cyclosporine use results from reduced degradation of extracellular matrix in the gingiva. Matrix metalloproteinase-3 (MMP-3) is involved in biodegradation of the extracellular matrix, and its inhibition may contribute to an abnormal accumulation of fibronectin and proteoglycans, which are MMP-3 substrates. The aim of this study was to investigate whether an association exists between MMP-3 genotypes and gingival enlargement in kidney transplant patients medicated with cyclosporine A. Sixty-four unrelated kidney transplant patients suffering from gingival overgrowth, as well as 111 control transplant patients without gingival overgrowth, were enrolled in the study. Gingival overgrowth was assessed 6 mo after transplantation. During the post-transplant period all patients were given cyclosporine A as a principal immunosuppressive agent. MMP-3 polymorphism was determined using a PCR restriction fragment length polymorphism assay. In kidney transplant patients suffering from gingival overgrowth the mean gingival overgrowth score was 1.35 +/- 0.57, whereas in control subjects the mean gingival overgrowth score was 0.0. The distribution of MMP-3-1178A/dupA alleles among all kidney transplant patients, as well as in the two study subgroups, did not differ significantly from Hardy-Weinberg equilibrium. The frequency of the MMP-3-1171A/A genotype (28.1% for gingival overgrowth vs. 26.1% for controls) and of the MMP-3-1171dupA/dupA genotype (32.8% for gingival overgrowth vs. 22.5% for controls) was similar for both study groups. The risk of gingival overgrowth was lowest among patients carrying the MMP-3-1171A/dupA genotype (odds ratio 0.52), but this did not differ markedly from the other genotypes. No association between MMP-3 gene polymorphism and gingival overgrowth was revealed in kidney transplant patients

Chronic administration of the selective P2X3, P2X2/3 receptor antagonist, A-317491, transiently attenuates cancer-induced bone pain in mice

DEFF Research Database (Denmark)

Hansen, Rikke Rie; Nasser, Arafat; Falk, Sarah

2012-01-01

The purinergic P2X3 and P2X2/3 receptors are in the peripheral nervous system almost exclusively confined to afferent sensory neurons, where they are found both at peripheral and central synapses. The P2X3 receptor is implicated in both neuropathic and inflammatory pain. However, the role of the ......X3 receptor in chronic cancer-induced bone pain is less known. Here we investigated the effect of systemic acute and chronic administration of the selective P2X3, P2X2/3 receptor antagonist (5-[[[(3-Phenoxyphenyl)methyl][(1S)-1,2,3,4-tetrahydro-1-naphthalenyl]amino]carbonyl]-1...

Matrix mineralogy of the Lance CO3 carbonaceous chondrite - A transmission electron microscope study

Science.gov (United States)

Keller, Lindsay P.; Buseck, Peter R.

1990-01-01

Results are presented on electron microprobe analyses of three CO chondrites, all of which are falls: Lance, Kainsaz, and Warrenton. The TEM mineralogy results of Lance chondrite show that Fe-rich matrix olivines have been altered to Fe-bearing serpentine and Fe(3+) oxide; matrix metal was also altered to produce Fe(3+) oxides, leaving the residual metal enriched in Ni. Olivine grains in Lance's matrix contain channels along their 100-line and 001-line directions; the formation and convergence of such channels resulted in a grain-size reduction of the olivine. A study of Kainsaz and Warrenton showed that these meteorites do not contain phyllosilicates in their matrices, although both contain Fe(3+) oxide between olivine grains. It is suggested that, prior to its alteration, Lance probably resembled Kainsaz, an unaltered CO3 chondrite.

Implication of the oligomeric state of the N-terminal PTX3 domain in cumulus matrix assembly.

Science.gov (United States)

Ievoli, Elena; Lindstedt, Ragnar; Inforzato, Antonio; Camaioni, Antonella; Palone, Francesca; Day, Anthony J; Mantovani, Alberto; Salvatori, Giovanni; Salustri, Antonietta

2011-06-01

Pentraxin 3 (PTX3) plays a key role in the formation of the hyaluronan-rich matrix of the cumulus oophorus surrounding ovulated eggs that is required for successful fertilization and female fertility. PTX3 is a multimeric protein consisting of eight identical protomers held together by a combination of non-covalent interactions and disulfide bonds. Recent findings suggest that the oligomeric status of PTX3 is important for stabilizing the cumulus matrix. Because the role of PTX3 in the cumulus resides in the unique N-terminal sequence of the protomer, we investigated further this issue by testing the ability of distinct Cys/Ser mutants of recombinant N-terminal region of PTX3 (N(_)PTX3) with different oligomeric arrangement to promote in vitro normal expansion in cumuli from Ptx3-null mice. Here we report that the dimer of the N(_)PTX3 is unable to rescue cumulus matrix organization, and that the tetrameric assembly of the protein is the minimal oligomeric state required for accomplishing this function. We have previously demonstrated that PTX3 binds to HCs of IαI and TSG-6, which are essential for cumulus matrix formation and able to interact with hyaluronan. Interestingly, here we show by solid-phase binding experiments that the dimer of the N(_)PTX3 retains the ability to bind to both IαI and TSG-6, suggesting that the octameric structure of PTX3 provides multiple binding sites for each of these ligands. These findings support the hypothesis that PTX3 contributes to cumulus matrix organization by cross-linking HA polymers through interactions with multiple HCs of IαI and/or TSG-6. The N-terminal PTX3 tetrameric oligomerization was recently reported to be also required for recognition and inhibition of FGF2. Given that this growth factor has been detected in the mammalian preovulatory follicle, we wondered whether FGF2 negatively influences cumulus expansion and PTX3 may also serve in vivo to antagonize its activity. We found that a molar excess of FGF2, above

Master formula approach to broken chiral U(3)xU(3) symmetry

Energy Technology Data Exchange (ETDEWEB)

Hiroyuki Kamano

2010-04-01

The master formula approach to chiral symmetry breaking proposed by Yamagishi and Zahed is extended to the U_R(3)xU_L(3) group, in which effects of the U_A(1) anomaly and the flavor symmetry breaking m_u \

Cast Aluminum Alloys for High Temperature Applications Using Nanoparticles Al2O3 and Al3-X Compounds (X = Ti, V, Zr)

Science.gov (United States)

Lee, Jonathan A.

2009-01-01

In this paper, the effect of nanoparticles Al2O3 and Al3-X compounds (X = Ti, V, Zr) on the improvement of mechanical properties of aluminum alloys for elevated temperature applications is presented. These nanoparticles were selected based on their low cost, chemical stability and low diffusions rates in aluminum at high temperatures. The strengthening mechanism at high temperature for aluminum alloy is based on the mechanical blocking of dislocation movements by these nanoparticles. For Al2O3 nanoparticles, the test samples were prepared from special Al2O3 preforms, which were produced using ceramic injection molding process and then pressure infiltrated by molten aluminum. In another method, Al2O3 nanoparticles can also be homogeneously mixed with fine aluminum powder and consolidated into test samples through hot pressing and sintering. With the Al3-X nanoparticles, the test samples are produced as precipitates from in-situ reactions with molten aluminum using conventional permanent mold or die casting techniques. It is found that cast aluminum alloy using nanoparticles Al3-X is the most cost effective method to produce high strength aluminum alloys for high temperature applications in comparison to nanoparticles Al2O3. Furthermore, significant mechanical properties retention in high temperature environment could be achieved with Al3-X nanoparticles, resulting in tensile strength of nearly 3 times higher than most 300- series conventional cast aluminum alloys tested at 600 F.

High energy neutrinos from Cyg X-3

International Nuclear Information System (INIS)

Walker, T.P.; Kolb, E.W.; Turner, M.S.

1985-07-01

Assuming that the UHE air showers from Cyg X-3 are produced by photons, we calculate the expected neutrino emission from a model which produces the γ-rays in the atmosphere of the Cyg X-3 companion. We discuss the possibility of detecting such neutrinos in underground detectors and the constraints that such a signal places on the use of this model in other particle production scenarios. 16 refs., 5 figs

Thermohydraulic tests of 3x3-rod bundle maquette

International Nuclear Information System (INIS)

Ladeira, L.C.D.

1986-10-01

The results of a 3x3-rod bundle thermohydraulic research program, performed in the Thermohydraulics Laboratory of NUCLEBRAS' Nuclear Technology Development Center, are briefly described. This program included measurements of pressure drops in one and two-phase flows, heat transfer coefficients, mixing between interconnected subchannels in one-phase flow conditions and critical heat fluxes. The measurements covered the following parameter ranges: heat fluxes from zero to the critical values, pressure ranging from 1 to 15 ata, inlet temperature from 25 to 150 sup(0)C and flow rate from 20 to 300l/min. (author)

Mixing transition-metal phosphates Li_3V_2_−_xFe_x(PO_4)_3 (0≤x≤2): the synthesis, structure and electrochemical properties

International Nuclear Information System (INIS)

Liu, Xudong; Zhao, Yanming; Kuang, Quan; Li, Xiaoming; Dong, Youzhong; Jing, Zhenzhen; Hou, Shiyu

2016-01-01

Highlights: • Monoclinic structure Li_3V_2_−_xFe_x(PO_4)_3 (0≤ x≤2) solid solutions have been successfully fabricated via a two-step synthesis method. • Trace amounts of acetylene black would play a role of deoxidizer during the sintering process in an inert atmosphere. • V1-site is the preferred position when Fe"3"+ ions doped into Li_3V_2(PO_4)_3 from our structural analysis. - Abstract: Mixing transition-metal phosphates Li_3V_2_−_xFe_x(PO_4)_3 (0≤x≤2) were first designed to be a type of intercalated and deintercalated cathodes to obtain high specific capacity for safe Li-ion batteries. Since the residual oxygen in the quartz tube furnace and pellet would oxidize the V"3"+ to V"4"+ in the Ar ambience during the sintering process, trace amounts of acetylene black inside and outside the pellet could play a role of deoxidizer to protect V"3"+ meanwhile ensure Fe"3"+ not reducing to Fe"2"+. With the concerted effort of inside and outside acetylene black, monoclinic structure Li_3V_2_−_xFe_x(PO_4)_3 (0≤x≤2) solid solutions had been successfully fabricated via a two-step synthesis method. X-ray diffractions with Rietveld refinement revealed that V1-sites were the preferred position when Fe"3"+ ions doped into Li_3V_2(PO_4)_3, which means, every V1-site was occupied with the same probability by V"3"+ and Fe"3"+ when 0< x<1, and then for V2-site when 1< x<2. X-ray photoelectron spectroscopy result showed the presence of trace amounts of acetylene black had realized the coexist of V"3"+ and Fe"3"+ in the Li_3M_2(PO_4)_3 framework. When evaluated as cathodes for Li-ion batteries, the pure Li_3V_2(PO_4)_3 electrode displayed the highest charge (137.2 mAh g"−"1) and discharge (121.5 mAh g"−"1) capacities in the first cycle, with the increase of Fe"3"+ content, all the charge and discharge capacities reduced drastically. Furthermore, the EIS results showed that the incorporation of the sluggish Fe"3"+ ions reduced the electronic conductivity and

Oxygen influencing the photocarriers lifetime of CH{sub 3}NH{sub 3}PbI{sub 3−x}Cl{sub x} film grown by two-step interdiffusion method and its photovoltaic performance

Energy Technology Data Exchange (ETDEWEB)

Yuan, Shuai; Qiu, Zhiwen; Zhang, Hailiang; Gong, Haibo; Cao, Bingqiang, E-mail: mse-caobq@ujn.edu.cn [Laboratory of Inorganic Energy and Environment Materials, School of Material Science and Engineering, University of Jinan, Jinan 250022, Shandong (China); Hao, Yufeng [Department of Mechanical Engineering, Columbia University, New York, New York 10027 (United States)

2016-01-18

During the growth of CH{sub 3}NH{sub 3}PbI{sub 3−x}Cl{sub x} (MAPbI{sub 3−x}Cl{sub x}) perovskite films by the two-step inter-diffusion method, the presence of a trace amount of oxygen gas is critical to their physical properties and photovoltaic performance. As the oxygen concentration increases, poor film morphologies and incomplete surface coverage are observed. Moreover, by XRD, Raman scattering, and photoluminescence measurements, we find that MAPbI{sub 3−x}Cl{sub x} grains become more distorted and the electron-hole recombination rate dramatically increases. Higher oxygen concentration triggers a sharp decrease in the current density and the fill factor of corresponding solar cells, which degrades device performance, on average, from 14.3% to 4.4%. This work proves the importance of controlling the oxygen atmosphere in the fabrication of high-performance perovskite solar cells.

PLOT-3D, Graphics Subroutines for 3-D Surface Plots with Arbitrary Rotations

International Nuclear Information System (INIS)

Basinger, D.; Gvildys, J.

1975-01-01

1 - Description of problem or function: PLOT-3D is a package of sub- programs designed to draw three-dimensional surfaces from arrays of points (x,y,z). The surfaces can be drawn after arbitrary rotations about the three coordinate axes. 2 - Method of solution: PLOT-3D is a computer program to plot any surface for which each coordinate pair (x,y) is associated with a unique z in the set of points (x,y,z). It uses matrix transformation of the points to generate different views of the surface after arbitrary rotations about the three coordinate axes. Four versions of PLOT-3D are available. Output of version 1 and 3 is by film recorder. Output of version 2 and 4 is by CalComp plotter. Versions 3 and 4 do not draw lines which would be invisible to a viewer looking at an opaque surface, whereas versions 1 and 2 draw every line on the surface. 3 - Restrictions on the complexity of the problem: Versions 3 and 4 limit number of rows in arrays (x,y,z) to 100 and also number of columns in arrays (x,y,z) to 100

Control of CydB and GltA1 expression by the SenX3 RegX3 two component regulatory system of Mycobacterium tuberculosis.

Directory of Open Access Journals (Sweden)

Gretta Roberts

Full Text Available Two component regulatory systems are used widely by bacteria to coordinate changes in global gene expression profiles in response to environmental signals. The SenX3-RegX3 two component system of Mycobacterium tuberculosis has previously been shown to play a role in virulence and phosphate-responsive control of gene expression. We demonstrate that expression of SenX3-RegX3 is controlled in response to growth conditions, although the absolute changes are small. Global gene expression profiling of a RegX3 deletion strain and wild-type strain in different culture conditions (static, microaerobic, anaerobic, as well as in an over-expressing strain identified a number of genes with changed expression patterns. Among those were genes previously identified as differentially regulated in aerobic culture, including ald (encoding alanine dehydrogenase cyd,encoding a subunit of the cytochrome D ubiquinol oxidase, and gltA1, encoding a citrate synthase. Promoter activity in the upstream regions of both cydB and gltA1 was altered in the RegX3 deletion strain. DNA-binding assays confirmed that RegX3 binds to the promoter regions of ald, cydB and gltA1 in a phosphorylation-dependent manner. Taken together these data suggest a direct role for the SenX-RegX3 system in modulating expression of aerobic respiration, in addition to its role during phosphate limitation.

Ag on Ge(111): 2D x-ray structure analysis of the #sq root#3 x #sq root#3 superstructure

DEFF Research Database (Denmark)

Dornisch, D.; Moritz, W.; Schulz, H.

1992-01-01

We have studied the Ag/Ge(111) square-root 3 x square-root 3 superstructure by grazing-incidence X-ray diffraction. In our structural analysis we find striking similarities to the geometry of Au on Si(111). The Ag atoms form trimer clusters with an Ag-Ag distance of 2.94 +/- 0.04 angstrom...

Single crystal neutron diffraction study of SrFeOsub(3-x)(x=0. 1)

Energy Technology Data Exchange (ETDEWEB)

Oda, H; Yamaguchi, Y; Takei, H; Watanabe, H [Tohoku Univ., Sendai (Japan). Research Inst. for Iron, Steel and Other Metals

1977-01-01

Neutron diffraction study was carried out on single crystals of the perovskite oxide SrFeOsub(3-x)(x=0.1). SrFeOsub(3-x)(x=0.1) has a proper screw spin structure with the propagation vector parallel to (111) direction and its Neel temperature is 118 K. The electron configuration of Fe/sup 4 +/(3d/sup 4/) ion is close to the low-spin state (tsub(2g)sup(4)) and the oxygen ion has the unpaired electron with the magnetic moment of 0.3..mu..sub(B) antiparallel to the vector sum of the magnetic moments of two iron ions lying on the neighbouring planes perpendicular to the screw axis. The absolute value of the propagation vector is almost constant. 0.130x..sqrt..3.2..pi../a A/sup -1/, at temperatures below 50 K, while it decreases gradually at higher temperatures reaching 0.118x..sqrt..3.2..pi../a A/sup -1/ at Tsub(N).

The electric field manipulation of magnetization in La{sub 1−x}Sr{sub x}CoO{sub 3}/Pb(Mg{sub 1/3}Nb{sub 2/3})O{sub 3}-PbTiO{sub 3} heterostructures

Energy Technology Data Exchange (ETDEWEB)

Zhang, Q. M.; Li, Q.; Zhou, W. P.; Wang, L. Y.; Yang, Y. T.; Wang, D. H., E-mail: wangdh@nju.edu.cn; Lv, L. Y.; Du, Y. W. [Jiangsu Key Laboratory for Nano Technology and National Laboratory of Solid State Microstructures, Nanjing University, Nanjing 210093 (China); Gao, R. L. [School of Metallurgy and Materials Engineering, Chongqing University of Science and Technology, Chongqing 401331 (China)

2014-04-07

La{sub 1−x}Sr{sub x}CoO{sub 3} (x = 0.18, 0.33, and 0.5) films were grown epitaxially on piezoelectric Pb(Mg{sub 1/3}Nb{sub 2/3})O{sub 3}-PbTiO{sub 3} substrates by pulsed laser deposition. The magnetization of these films varies with the external electric field, showing the magnetoelectric effect. With different doping content of Sr{sup 2+} ions, the change of magnetization for these films show different behaviors with increasing temperature, which can be attributed to the competition between electric-field-induced changes of spin state and double exchange interaction. This work presents an alternative mechanism to investigate the electric field control of magnetism in magnetoelectric heterostructure by tuning the spin state.

Transport and magnetic properties of Pr1-x Ca x MnO3 epitaxial films grown on LaAlO3 substrates

International Nuclear Information System (INIS)

Maniwa, A.; Okano, K.; Ohkubo, I.; Kumigashira, H.; Oshima, M.; Lippmaa, M.; Kawasaki, M.; Koinuma, H.

2007-01-01

We have measured physical properties of Pr 1- x Ca x MnO 3 (PCMO) epitaxial thin films with different hole concentrations (x=0.2, 0.3, 0.4, and 0.5) grown on LaAlO 3 (1 0 0) substrates by laser molecular beam epitaxy technique. The temperature dependence of the resistivity shows insulating behavior in all temperature regions and the resistivity itself monotonously decreases as x increases. This insulating nature of PCMO films is similar to that of bulk PCMO crystals. However, we did not find any indication of the resistivity anomaly associated with the onset of charge ordering irrespective of x. These results suggest that the compressive strain strongly suppresses charge-ordered states in PCMO

Synthesis and X-ray diffraction studies of dysprosium-calcium ferrites Dy1-xCaxFeO3-y (0≤x≤2/3)

International Nuclear Information System (INIS)

Li, J.; Song, D.; Su, Z.; Wang, T.M.

1997-01-01

Samples of dysprosium-calcium ferrites Dy 1-x Ca x FeO 3-y with x ranging from 0 to 2/3 were novelly prepared in air by solid state reaction and characterized by X-ray powder diffraction. These samples are single-phased orthorhombic perovskite-type compounds belonging to the space group D 2h 16 -Pbnm. The lattice constants of the Dy 1-x Ca x FeO 3-y samples have been refined by Cohen's least-squares method. The initial substitution of Ca for Dy leads to a decrease of the lattice constants. Further substitution of Ca for Dy has hardly any influence on the lattice dimensions. (orig.)

Enhanced Crystalline Phase Purity of CH3NH3PbI3-xClx Film for High-Efficiency Hysteresis-Free Perovskite Solar Cells.

Science.gov (United States)

Yang, Yingguo; Feng, Shanglei; Xu, Weidong; Li, Meng; Li, Li; Zhang, Xingmin; Ji, Gengwu; Zhang, Xiaonan; Wang, Zhaokui; Xiong, Yimin; Cao, Liang; Sun, Baoquan; Gao, Xingyu

2017-07-12

Despite rapid successful developments toward promising perovskite solar cells (PSCs) efficiency, they often suffer significant hysteresis effects. Using synchrotron-based grazing incidence X-ray diffraction (GIXRD) with different probing depths by varying the incident angle, we found that the perovskite films consist of dual phases with a parent phase dominant in the interior and a child phase with a smaller (110) interplanar space (d (110) ) after rapid thermal annealing (RTA), which is a widely used post treatment to improve the crystallization of solution-processed perovskite films for high-performance planar PSCs. In particular, the child phase composition gradually increases with decreasing depth till it becomes the majority on the surface, which might be one of the key factors related to hysteresis in fabricated PSCs. We further improve the crystalline phase purity of the solution-processed CH 3 NH 3 PbI 3-x Cl x perovskite film (referred as g-perovskite) by using a facile gradient thermal annealing (GTA), which shows a uniformly distributed phase structure in pinhole-free morphology with less undercoordinated Pb and I ions determined by synchrotron-based GIXRD, grazing incidence small-angle X-ray scattering, scanning electron microscopy, and X-ray photoelectron spectroscopy. Regardless of device structures (conventional and inverted types), the planar heterojunction PSCs employing CH 3 NH 3 PbI 3-x Cl x g-perovskite films exhibit negligible hysteresis with a champion power conversion efficiency of 17.04% for TiO 2 -based conventional planar PSCs and 14.83% for poly(3,4-ethylenedioxythiophene:poly(styrenesulfonate) (PEDOT:PSS)-based inverted planar PSCs. Our results indicate that the crystalline phase purity in CH 3 NH 3 PbI 3-x Cl x perovskite film, especially in the surface region, plays a crucial role in determining the hysteresis effect and device performance.

Magnetic properties of (Mn1-xRux)3Ga alloys

International Nuclear Information System (INIS)

Hori, T.; Akimitsu, M.; Miki, H.; Ohoyoama, K.; Yamaguchi, Y.

2002-01-01

We found that the pseudo binary alloys Mn 1-x Ru x 3 Ga, with 0.33≤x≤0.67, have an ordered b.c.c. structure. The lattice constant a is almost constant with respect to x: a=6.000 A for x=0.33 and a=5.992 A for x=0.67. For the alloy with x=0.33, i.e. Mn 2 RuGa, the magnetization is almost saturated in a field of 20 kOe. The saturation magnetization at 4.2 K is 23 emu/g, and the Curie temperature, T C , is 460 K. The T C of (Mn 1-x Ru x ) 3 Ga decreases almost linearly with increasing x, and it vanishes around x=0.67 (MnRu 2 Ga). We also determined atomic and magnetic structures from neutron diffraction experiments. The alloy Mn 2 RuGa (x=0.33) has an ordered structure of CuHg 2 Ti type; the magnetic Mn atoms mainly occupy the 4a (0,0,0) and 4d (3/4,3/4,3/4) sites. We also observed that the magnetic moments of Mn atoms on the 4a and 4d sites are antiparallel to each other; values of the magnetic moment are μ a =4.6 and μ d =3.3 μ B per Mn atom. (orig.)

Cluster-enhanced X-O-2 photochemistry (X=CH3I, C3H6, C6H12, and Xe)

NARCIS (Netherlands)

Baklanov, A.V.; Bogdanchikov, G.A.; Vidma, K.V.; Chestakov, D.A.; Parker, D.H.

2007-01-01

The effect of a local environment on the photodissociation of molecular oxygen is investigated in the van der Waals complex X-O-2 (X=CH3I, C3H6, C6H12, and Xe). A single laser operating at wavelengths around 226 nm is used for both photodissociation of the van der Waals complex and simultaneous

Maintenance of neural progenitor cell stemness in 3D hydrogels requires matrix remodelling

Science.gov (United States)

Madl, Christopher M.; Lesavage, Bauer L.; Dewi, Ruby E.; Dinh, Cong B.; Stowers, Ryan S.; Khariton, Margarita; Lampe, Kyle J.; Nguyen, Duong; Chaudhuri, Ovijit; Enejder, Annika; Heilshorn, Sarah C.

2017-12-01

Neural progenitor cell (NPC) culture within three-dimensional (3D) hydrogels is an attractive strategy for expanding a therapeutically relevant number of stem cells. However, relatively little is known about how 3D material properties such as stiffness and degradability affect the maintenance of NPC stemness in the absence of differentiation factors. Over a physiologically relevant range of stiffness from ~0.5 to 50 kPa, stemness maintenance did not correlate with initial hydrogel stiffness. In contrast, hydrogel degradation was both correlated with, and necessary for, maintenance of NPC stemness. This requirement for degradation was independent of cytoskeletal tension generation and presentation of engineered adhesive ligands, instead relying on matrix remodelling to facilitate cadherin-mediated cell-cell contact and promote β-catenin signalling. In two additional hydrogel systems, permitting NPC-mediated matrix remodelling proved to be a generalizable strategy for stemness maintenance in 3D. Our findings have identified matrix remodelling, in the absence of cytoskeletal tension generation, as a previously unknown strategy to maintain stemness in 3D.

H3(+) as a trap for noble gases-3: multiple trapping of neon, argon, and krypton in X(n)H3(+) (n = 1-3).

Science.gov (United States)

Pauzat, F; Ellinger, Y; Pilmé, J; Mousis, O

2009-05-07

Recent studies on the formation of XH(3)(+) noble gas complexes have shown strategic implications for the composition of the atmospheres of the giant planets as well as for the composition of comets. One crucial factor in the astrophysical process is the relative abundances of the noble gases versus H(3)(+). It is the context in which the possibility for clustering with more than one noble gas (X(n)H(3)(+) up to n = 3) has been investigated for noble gases X ranging from neon to krypton. In order to assert our results, a variety of methods have been used including ab initio coupled cluster CCSD and CCSD(T), MP2, and density functional BH&HLYP levels of theory. All complexes with one, two, and three noble gases are found to be stable in the Ne, Ar, and Kr families. These stable structures are planar with the noble gases attached to the apices of the H(3)(+) triangle. The binding energy of the nth atom, defined as the X(n)H(3)(+) --> X(n-1)H(3)(+) + X reaction energy, increases slightly with n varying from 1 to 3 in the neon series, while it decreases in the argon series and shows a minimum for n = 2 in the krypton series. The origin of this phenomenon is to be found in the variations in the respective vibrational energies. A topological analysis of the electron localization function shows the importance of the charge transfer from the noble gases toward H(3)(+) as a driving force in the bonding along the series. It is also consistent with the increase in the atomic polarizabilities from neon to krypton. Rotational constants and harmonic frequencies are reported in order to provide a body of data to be used for the detection in laboratory prior to space observations. This study strongly suggests that the noble gases could be sequestered even in an environment where the H(3)(+) abundance is small.

[In Vitro and In Vivo Biocompatibility of a Novel, 3-Dimensional Cellulose Matrix Structure].

Science.gov (United States)

Dunda, S E; Ranker, M; Pallua, N; Machens, H-G; Ravichandran, A; Schantz, J-T

2015-12-01

Biological and physical characteristics of matrices are one essential factor in creating bioartificial tissue. In this study, a new 3-dimensional cellulose matrix (Xellulin(®)) was tested in terms of biocompatibility and applicability for tissue engineering in vitro and in vivo. The tested matrix Xellulin(®) is a natural hydrological gel-matrix containing bacterial cellulose and water. To evaluate the cell biocompatibilty, cell adherence and proliferation characteristics in vitro, the matrix was cultured with human fibroblasts. Further in vivo studies were carried out by transplanting preadipocytes of 4- to 6-week-old Wistar rats with 3 different conditions: a) Xellulin(®) including 500 000 preadipocytes subcutaneous, b) Xellulin(®) including 500 000 preadipocytes within an in vivo bioreactor chamber, c) Xellulin(®) without cells subcutaneous as control. After explantation on day 14 histomorphological and immunohistochemical evaluations were performed. In vitro study revealed an excellent biocompatibility with good cell adherence of the fibroblasts on the matrix and evidence of cell proliferation and creation of a 3-dimensional cell network. In vivo neocapillarisation could be shown in all groups with evidence of erythrocytes (H/E staining) and endothelial vascular cells (RECA-1-staining). A significantly higher vascular density was shown in vascularised bioreactor group (18.4 vessels/100 000 µm(2) (group b) vs. 8.1 (group a), pmatrix was noticed. The promising in vitro results concerning cell adherence and proliferation on the tested matrix could be confirmed in vivo with an evidence of 3-dimensional neocapillarisation. Cell survival was higher in the vascularised group, but without significance. Long-term tests (28-42 days) need to be carried out to evaluate long-term cell survival and the matrix stability. Furthermore, studies concerning the implementation of the matrix within anatomic structures as well as long-term biocompatibility are needed. �

High energy X-ray observation of Cyg X-3

International Nuclear Information System (INIS)

Kendziorra, E.; Pietsch, W.; Staubert, R.; Truemper, J.

1975-01-01

On Feb. 20, 1975 Cyg X-3 was observed in the energy range of 29-70 keV during a 5 hour observation of the Cyg region. An intensity variation consistent with a 4.8 h sinusoidal modulation has been found, in phase with low energy X-ray observations and with a relative amplitude of 0.37 +- 0.19. (orig.) [de

Characterization of Mixed xWO3(1-xY2O3 Nanoparticle Thick Film for Gas Sensing Application

Directory of Open Access Journals (Sweden)

M. H. Shahrokh Abadi

2010-05-01

Full Text Available Microstructural, topology, inner morphology, and gas-sensitivity of mixed xWO3(1-xY2O3 nanoparticles (x = 1, 0.95, 0.9, 0.85, 0.8 thick-film semiconductor gas sensors were studied. The surface topography and inner morphological properties of the mixed powder and sensing film were characterized with X-ray diffraction (XRD, atomic force microscopy (AFM, transmission electron microscopy (TEM, and scanning electron microscopy (SEM. Also, gas sensitivity properties of the printed films were evaluated in the presence of methane (CH4 and butane (C4H10 at up to 500 °C operating temperature of the sensor. The results show that the doping agent can modify some structural properties and gas sensitivity of the mixed powder.

Enhanced photovoltaic performance of CH3NH3PbBrXI3-X-based perovskite solar cells via anti-solvent extraction

Science.gov (United States)

Jiang, Zhaoyi; Zhang, Weijia; Lu, Chaoqun; Ma, Denghao; Liu, Haixu; Yu, Wei; Zhang, Yu; Ma, Qiang; Zhang, Yulong

2018-06-01

In this paper, the two-step sequential deposition method was used to prepare the CH3NH3PbBrXI3-X films by introducing CH3NH3Br in the precursors. The surface morphology of the PbI2 films was controlled by anti-solvent extraction (ASE) to improve the microstructure and photo-physical properties of the perovskite films. It was noteworthy that, compared to the compact PbI2 films, the porous PbI2 films facilitated the growth of crystals and bromine incorporation in films, and the prepared perovskite films exhibited enlarged grain size, increased light absorption, enhanced Br incorporation and prolonged carrier lifetime, which resulted in excellent photo-electrical properties of the CH3NH3PbBrXI3-X films. With porous PbI2 templates, the inverted planar perovskite solar cells based on films with appropriate Br incorporation (CH3NH3Br/CH3NH3I mole ratio = 3/7) showed a photovoltaic conversion efficiency (PCE) of 14.9%, and the stability of the devices in air was elevated. Consequently, the high-quality CH3NH3PbBrXI3-X films can be obtained with porous PbI2 templates for improving the performance of the perovskite solar cells.

NpX3 compounds under high pressure

International Nuclear Information System (INIS)

Zwirner, S.; Kalvius, G.M.

1993-01-01

The systematics of hyperfine interactions and the ordering temperature T ord in isostructural NpX 3 compounds (X=Al, Si, Ga, Ge, ln, Sn) are briefly reviewed. NpSn 3 has been viewed as a Kondo lattice system, similar to CeAl 2 , NpIn 3 shows a modulated magnetic structure including low moment and nonmagnetic contributions at ambient pressure and 4.2 K. Preliminary results of recent 237 Np Moessbauer studies on NpIn 3 at ambient pressure and various temperatures and at 4.0(8) GPa and 4.2 K are reported. At 4.0(8) GPa, T ord rises from 17 to 22 K, the low-moment contributions of the modulated structure are reduced and the non-magnetic site is lost below T ord . The variation of the hyperfine parameters and of T ord with pressure is similar to the behavior observed in NpSn 3 . (orig.)

Magnesium replacement in formaldehyde: Theoretical rovibrational analysis of X ∼ 3B1 MgCH2

Science.gov (United States)

Bassett, Matthew K.; Fortenberry, Ryan C.

2018-02-01

A full, anharmonic set of fundamental vibrational frequencies as well as spectrosocpic constants are provided at high-level for X ∼ 3B1 MgCH2 for the first time. The present data are in line with previous computational and Ar-matrix results, but the anharmonic data show that two brightest frequencies, ν4 and ν5 , are nearly coincident with one another at 560 cm-1. Hence, this area is the best spectral region to search for signatures of this molecule. The rotational constants are also provided indicating a near-prolate rotational progression which should aid in microwave/millimeter-wave analysis of this molecule. Magnesium is known to be a significant component of the Earth, and molecules containing it may be more common in the interstellar medium/circumstellar media than previously thought. More spectral characterization of such molecules like MgCH2 should be undertaken, and this work is a step in that direction.

Modifying a numerical algorithm for solving the matrix equation X + AX T B = C

Science.gov (United States)

Vorontsov, Yu. O.

2013-06-01

Certain modifications are proposed for a numerical algorithm solving the matrix equation X + AX T B = C. By keeping the intermediate results in storage and repeatedly using them, it is possible to reduce the total complexity of the algorithm from O( n 4) to O( n 3) arithmetic operations.

Electronic and optical properties of MAPbX3 perovskites (X = I, Br, Cl): a unified DFT and GW theoretical analysis.

Science.gov (United States)

Mosconi, Edoardo; Umari, Paolo; De Angelis, Filippo

2016-10-05

Materials engineering is a key for the enhancement of photovoltaics technology. This is particularly true for the novel class of perovskite solar cells. Accurate theoretical modelling can help establish general trends of behavior when addressing structural changes. Here, we consider the effects due to halide substitution in organohalide CH 3 NH 3 PbX 3 perovskites exploring the halide series with X = Cl, Br, I. For this task, we use accurate DFT and GW methods including spin-orbit coupling. We find the expected band gap increase when moving from X = I to Cl, in line with the experimental data. Most notably, the calculated absorption coefficients for I, Br and Cl are nicely reproducing the behavior reported experimentally. A common feature of all the simulated band structures is a significant Rashba effect. This is similar for MAPbI 3 and MAPbBr 3 while MAPbCl 3 shows in general a reduced Rashba interaction coefficient. Finally, a monotonic increase of the exciton reduced masses is calculated when moving from I to Br to Cl, in line with the stronger excitonic character of the lighter perovskite halides.

Thermal conductivity in Pr{sub 1-x}Ca{sub x}MnO{sub 3} and SrTiO{sub 3} thin film systems

Energy Technology Data Exchange (ETDEWEB)

Wiedigen, Stefanie; Kramer, Thilo; Mangipudi, Kodanda R.; Hoffmann, Joerg; Volkert, Cynthia A.; Jooss, Christian [Institute for Materials Physics, University of Goettingen (Germany); Feuchter, Manuel; Kamlah, Marc [Institute for Applied Materials, Karlsruhe Institute of Technology (Germany)

2012-07-01

Epitaxial multilayers and superlattices are one recent approach for the design of efficient thermoelectrics. To study the effect of phonon blocking and scattering on thermal conductivity of oxide multilayers, a combination of two perovskites with promising thermoelectric properties is selected: the orthorhombic Pr{sub 1-x}Ca{sub x}MnO{sub 3} and the cubic SrTiO{sub 3}. In order to investigate the effect of microstructure, interfaces and acoustic impedance mismatch on thermal conductivity {kappa} high preparation quality is needed. Our thin films were prepared by ion-beam and magnetron sputtering. Structural analysis is done by XRD and TEM and is presented in combination with thermal conductivity measurements using the 3{omega} method. Single layers of Pr{sub 1-x}Ca{sub x}MnO{sub 3} show low {kappa} values and no significant increase of thermal conductivity with increasing doping. In homoepitaxial single layers of SrTiO{sub 3} preparation conditions have a high impact on {kappa}, most probably due to different concentrations of point defects. Pr{sub 1-x}Ca{sub x}MnO{sub 3}/SrTiO{sub 3} multilayers show a {kappa} decreases systematically with increasing number of double layers. The results are discussed in the light of the theoretically calculated phonon dispersion and the experimentally observed microstructure.

Microstructure and Properties of Fe3Al-Fe3AlC x Composite Prepared by Reactive Liquid Processing

Science.gov (United States)

Verona, Maria Nalu; Setti, Dalmarino; Paredes, Ramón Sigifredo Cortés

2018-04-01

A Fe3Al-Fe3AlC x composite was prepared using reactive liquid processing (RLP) through controlled mixture of carbon steel and aluminum in the liquid state. The microstructure and phases of the composite were assessed using X-ray diffraction, scanning electron microscopy, energy-dispersive X-ray spectroscopy, optical microscopy, and differential scanning calorimetry. In addition, the density, hardness, microhardness, and elastic modulus were evaluated. The Fe3Al-Fe3AlC x composite consisted of 65 vol pct Fe3Al and 35 vol pct Fe3AlC x ( κ). The κ phase contained 10.62 at. pct C, resulting in the stoichiometry Fe3AlC0.475. The elastic modulus of the Fe3Al-Fe3AlC0.475 composite followed the rule of mixtures. The RLP technique was shown to be capable of producing Fe3Al-Fe3AlC0.475 with a microstructure and properties similar to those achieved using other processing techniques reported in the literature.

Energy-band alignment of (HfO2)x(Al2O3)1-x gate dielectrics deposited by atomic layer deposition on β-Ga2O3 (-201)

Science.gov (United States)

Yuan, Lei; Zhang, Hongpeng; Jia, Renxu; Guo, Lixin; Zhang, Yimen; Zhang, Yuming

2018-03-01

Energy band alignments between series band of Al-rich high-k materials (HfO2)x(Al2O3)1-x and β-Ga2O3 are investigated using X-Ray Photoelectron Spectroscopy (XPS). The results exhibit sufficient conduction band offsets (1.42-1.53 eV) in (HfO2)x(Al2O3)1-x/β-Ga2O3. In addition, it is also obtained that the value of Eg, △Ec, and △Ev for (HfO2)x(Al2O3)1-x/β-Ga2O3 change linearly with x, which can be expressed by 6.98-1.27x, 1.65-0.56x, and 0.48-0.70x, respectively. The higher dielectric constant and higher effective breakdown electric field of (HfO2)x(Al2O3)1-x compared with Al2O3, coupled with sufficient barrier height and lower gate leakage makes it a potential dielectric for high voltage β-Ga2O3 power MOSFET, and also provokes interest in further investigation of HfAlO/β-Ga2O3 interface properties.

Physical properties of laser-ablated La1-xSrxCoO3-δ films

International Nuclear Information System (INIS)

Park, J. S.; Park, S. Y.; Park, H. G.; Kim, S. M.; Lee, Y. P.; Prokhorov, V. G.; Ishchuk, V. M.

2002-01-01

The magnetic and the transport properties of La 1-x Sr x CoO 3 films prepared by using laser ablation were investigated. The metal-insulator transition was observed with decreasing Sr 2+ doping (x ≤ 0.25). The temperature-dependent resistivity, ρ(T), in the metallic state was shown to be governed by electron-electron scattering by taking into account the origin of a small energy gap in the spectrum of electron excitations. The analysis of the ρ(T) data showed that the transport of carriers at high temperatures (above the temperature of the magnetic transition) in the insulating state (x ≤ 0.25) was governed by Mott-like variable-range hopping rather than by the motion of lattice polarons. In the low-temperature range, the ρ(T) dependence was fairly well fitted by using the two parallel-resistance model, where one resistance corresponded to the ferromagnetic metal cluster network and the other to the insulating matrix. Two mechanisms of magnetoresistance were involved in the investigated films. In the metallic state (x > 0.25) the magnetoresistance was provided by a change in the rate of electron scattering with spin disorder, which was influenced by the magnetic field and resulted in a small peak at the Curie temperature. In the insulating state (x ≤ 0.25), a phase separation into ferromagnetic metal clusters and the insulating matrix occurred, and an applied magnetic field induced the growth of the ferromagnetic metal phase, with the double-exchange mechanism not playing a role

Magnetic and magnetocaloric properties of La{sub 0.7}Ca{sub 0.3}Mn{sub 1−x}Zn{sub x}O{sub 3}

Energy Technology Data Exchange (ETDEWEB)

Ho, T.A. [Department of Materials Science and Engineering, Korea University, Seoul 02841 (Korea, Republic of); Lim, S.H., E-mail: sangholim@korea.ac.kr [Department of Materials Science and Engineering, Korea University, Seoul 02841 (Korea, Republic of); Tho, P.T.; Phan, T.L. [Department of Physics and Oxide Research Center, Hankuk University of Foreign Studies, Yongin 17035 (Korea, Republic of); Yu, S.C. [Department of Physics, Chungbuk National University, Cheongju 28644 (Korea, Republic of)

2017-03-15

The magnetic Mn{sup 3+} ions in La{sub 0.7}Ca{sub 0.3}MnO{sub 3} are partially replaced by nonmagnetic Zn{sup 2+} ions to form La{sub 0.7}Ca{sub 0.3}Mn{sub 1−x}Zn{sub x}O{sub 3} compounds (x=0.0, 0.06, 0.08, and 0.1), and their magnetic and magnetocaloric properties are investigated. The Curie temperature decreases drastically from 245 to 70 K as x increases from 0 to 0.1. An analysis using the Banerjee's criterion of the experimental results for magnetization as a function of temperature and magnetic field indicates that the first-to-second order magnetic phase transformation occurs at a threshold composition of x=0.06, which is further supported by the universal curves of the normalized entropy change versus reduced temperature. The maximum magnetic entropy change measured at a magnetic field span of 50 kOe, which occurs near the Curie temperature, decreases from 10.30 to 2.15 J/kg K with the increase of x from 0.0 to 0.1. However, the relative cooling power, an important parameter for practical applications, shows a maximum value of 404 J/kg at x=0.08, which is 1.5 times greater than that observed for the undoped sample. - Highlights: • Magnetic and MCE of La{sub 0.7}Ca{sub 0.3}Mn{sub 1−x}Zn{sub x}O{sub 3} are investigated. • Order of magnetic phase transition is dependent on the Zn doping concentration. • Although the |∆S{sub max}| decreases with increasing x, RCP increase remarkably.

Phase equilibria in the Mo-Fe-P system at 800 °C and structure of ternary phosphide (Mo(1-x)Fe(x))3P (0.10 ≤ x ≤ 0.15).

Science.gov (United States)

Oliynyk, Anton O; Lomnytska, Yaroslava F; Dzevenko, Mariya V; Stoyko, Stanislav S; Mar, Arthur

2013-01-18

Construction of the isothermal section in the metal-rich portion (ternary phases: (Mo(1-x)Fe(x))(2)P (x = 0.30-0.82) and (Mo(1-x)Fe(x))(3)P (x = 0.10-0.15). The occurrence of a Co(2)Si-type ternary phase (Mo(1-x)Fe(x))(2)P, which straddles the equiatomic composition MoFeP, is common to other ternary transition-metal phosphide systems. However, the ternary phase (Mo(1-x)Fe(x))(3)P is unusual because it is distinct from the binary phase Mo(3)P, notwithstanding their similar compositions and structures. The relationship has been clarified through single-crystal X-ray diffraction studies on Mo(3)P (α-V(3)S-type, space group I42m, a = 9.7925(11) Å, c = 4.8246(6) Å) and (Mo(0.85)Fe(0.15))(3)P (Ni(3)P-type, space group I4, a = 9.6982(8) Å, c = 4.7590(4) Å) at -100 °C. Representation in terms of nets containing fused triangles provides a pathway to transform these closely related structures through twisting. Band structure calculations support the adoption of these structure types and the site preference of Fe atoms. Electrical resistivity measurements on (Mo(0.85)Fe(0.15))(3)P reveal metallic behavior but no superconducting transition.

CsPbBr{sub 3} QD/AlO{sub x} inorganic nanocomposites with exceptional stability in water, light, and heat

Energy Technology Data Exchange (ETDEWEB)

Loiudice, Anna; Saris, Seryio; Buonsanti, Raffaella [Department of Chemical Sciences and Engineering, EPFL Valais Wallis, Sion (Switzerland); Oveisi, Emad; Alexander, Duncan T.L. [Interdisciplinary Centre for Electron Microscopy (CIME), EPFL, Lausanne (Switzerland)

2017-08-28

Herein, the assembly of CsPbBr{sub 3} QD/AlO{sub x} inorganic nanocomposites, by using atomic layer deposition (ALD) for the growth of the amorphous alumina matrix (AlO{sub x}), is described as a novel protection scheme for such QDs. The nucleation and growth of AlO{sub x} on the QD surface was thoroughly investigated by miscellaneous techniques, which highlighted the importance of the interaction between the ALD precursors and the QD surface to uniformly coat the QDs while preserving the optoelectronic properties. These nanocomposites show exceptional stability towards exposure to air (for at least 45 days), irradiation under simulated solar spectrum conditions (for at least 8 h), and heat (up to 200 C in air), and finally upon immersion in water. This method was extended to the assembly of CsPbBr{sub x}I{sub 3-x} QD/AlO{sub x} and CsPbI{sub 3} QD/AlO{sub x} nanocomposites, which were more stable than the pristine QD films. (copyright 2017 Wiley-VCH Verlag GmbH and Co. KGaA, Weinheim)

A study on the damping capacity of BaTiO3-reinforced Al-matrix ...

Indian Academy of Sciences (India)

the results showed that the damping capacity of Al-matrix composites can increase greatly [3–5]. Therefore, reinforcing. Al alloy matrix with higher damping particles could be an efficient way to obtain Al-matrix composites with both high strength and high damping capacity. Ferroelectric and piezoelectric ceramics can exhibit ...

Homogeneous Emission Line Broadening in the Organo Lead Halide Perovskite CH3NH3PbI3-xClx.

Science.gov (United States)

Wehrenfennig, Christian; Liu, Mingzhen; Snaith, Henry J; Johnston, Michael B; Herz, Laura M

2014-04-17

The organic-inorganic hybrid perovskites methylammonium lead iodide (CH3NH3PbI3) and the partially chlorine-substituted mixed halide CH3NH3PbI3-xClx emit strong and broad photoluminescence (PL) around their band gap energy of ∼1.6 eV. However, the nature of the radiative decay channels behind the observed emission and, in particular, the spectral broadening mechanisms are still unclear. Here we investigate these processes for high-quality vapor-deposited films of CH3NH3PbI3-xClx using time- and excitation-energy dependent photoluminescence spectroscopy. We show that the PL spectrum is homogenously broadened with a line width of 103 meV most likely as a consequence of phonon coupling effects. Further analysis reveals that defects or trap states play a minor role in radiative decay channels. In terms of possible lasing applications, the emission spectrum of the perovskite is sufficiently broad to have potential for amplification of light pulses below 100 fs pulse duration.

Mixed Matrix Carbon Molecular Sieve and Alumina (CMS-Al2O3) Membranes.

Science.gov (United States)

Song, Yingjun; Wang, David K; Birkett, Greg; Martens, Wayde; Duke, Mikel C; Smart, Simon; Diniz da Costa, João C

2016-07-29

This work shows mixed matrix inorganic membranes prepared by the vacuum-assisted impregnation method, where phenolic resin precursors filled the pore of α-alumina substrates. Upon carbonisation, the phenolic resin decomposed into several fragments derived from the backbone of the resin matrix. The final stages of decomposition (>650 °C) led to a formation of carbon molecular sieve (CMS) structures, reaching the lowest average pore sizes of ~5 Å at carbonisation temperatures of 700 °C. The combination of vacuum-assisted impregnation and carbonisation led to the formation of mixed matrix of CMS and α-alumina particles (CMS-Al2O3) in a single membrane. These membranes were tested for pervaporative desalination and gave very high water fluxes of up to 25 kg m(-2) h(-1) for seawater (NaCl 3.5 wt%) at 75 °C. Salt rejection was also very high varying between 93-99% depending on temperature and feed salt concentration. Interestingly, the water fluxes remained almost constant and were not affected as feed salt concentration increased from 0.3, 1 and 3.5 wt%.

BSRF-3B3 Medium Energy X-ray Beamline and Its Application for XAFS Research

International Nuclear Information System (INIS)

Ma Chenyan; Cui Mingqi; Zhou Kejin; Zhao Yidong; Tian Yulian; Wu Ziyu; Zheng Lei; Zhu Jie; Zhao Jia; Chen Kai; Sun Lijuan

2007-01-01

A new medium X-ray beamline 3B3 covering energy from 1.2 keV up to 6.0 keV was built at Beijing Synchrotron Radiation Facility (BSRF) in 2005. With perfect capability of high monochromaticity, good focus and low harmonics, it could be applied to study metrology, optic component characteristics and medium X-ray absorption spectroscopy (XAS). A simple XAFS apparatus has been set up and some measurements such as S, P, Cl, Ca, Al, Mg K-edge X-ray absorption fine structure (XAFS) in their compounds have also been carried out. The results show that it is feasible to do XAFS research at 3B3 beamline under present condition. The fabrication of a more delicate medium XAFS spectrometer is underway including transmission, fluorescence and electronic yield modes

The solubility and site preference of Fe{sup 3+} in Li{sub 7−3x}Fe{sub x}La{sub 3}Zr{sub 2}O{sub 12} garnets

Energy Technology Data Exchange (ETDEWEB)

Rettenwander, D., E-mail: daniel.rettenwander@sbg.ac.at [Department of Materials Research and Physics, University of Salzburg, 5020 Salzburg (Austria); Geiger, C.A. [Department of Materials Research and Physics, University of Salzburg, 5020 Salzburg (Austria); Tribus, M.; Tropper, P. [Institute of Mineralogy and Petrography, Faculty of Geo- and Atmospheric Sciences, University of Innsbruck, Innrain 52, 6020 Innsbruck (Austria); Wagner, R.; Tippelt, G.; Lottermoser, W.; Amthauer, G. [Department of Materials Research and Physics, University of Salzburg, 5020 Salzburg (Austria)

2015-10-15

A series of Fe{sup 3+}-bearing Li{sub 7}La{sub 3}Zr{sub 2}O{sub 12} (LLZO) garnets was synthesized using solid-state synthesis methods. The synthetic products were characterized compositionally using electron microprobe analysis and inductively coupled plasma optical emission spectroscopy (ICP-OES) and structurally using X-ray powder diffraction and {sup 57}Fe Mössbauer spectroscopy. A maximum of about 0.25 Fe{sup 3+} pfu could be incorporated in Li{sub 7−3x}Fe{sub x}La{sub 3}Zr{sub 2}O{sub 12} garnet solid solutions. At Fe{sup 3+} concentrations lower than about 0.16 pfu, both tetragonal and cubic garnets were obtained in the synthesis experiments. X-ray powder diffraction analysis showed only a garnet phase for syntheses with starting materials having intended Fe{sup 3+} contents lower than 0.52 Fe{sup 3+} pfu. Back-scattered electron images made with an electron microprobe also showed no phase other than garnet for these compositions. The lattice parameter, a{sub 0}, for all solid-solution garnets is similar with a value of a{sub 0}≈12.98 Å regardless of the amount of Fe{sup 3+}. {sup 57}Fe Mössbauer spectroscopic measurements indicate the presence of poorly- or nano-crystalline FeLaO{sub 3} in syntheses with Fe{sup 3+} contents greater than 0.16 Fe{sup 3+} pfu. The composition of different phase pure Li{sub 7−3x}Fe{sub x}La{sub 3}Zr{sub 2}O{sub 12} garnets, as determined by electron microprobe (Fe, La, Zr) and ICP-OES (Li) measurements, give Li{sub 6.89}Fe{sub 0.03}La{sub 3.05}Zr{sub 2.01}O{sub 12}, Li{sub 6.66}Fe{sub 0.06}La{sub 3.06}Zr{sub 2.01}O{sub 12}, Li{sub 6.54}Fe{sub 0.12}La{sub 3.01}Zr{sub 1.98}O{sub 12}, and Li{sub 6.19}Fe{sub 0.19}La{sub 3.02}Zr{sub 2.04}O{sub 12}. The {sup 57}Fe Mössbauer spectrum of cubic Li{sub 6.54}Fe{sub 0.12}La{sub 3.01}Zr{sub 1.98}O{sub 12} garnet indicates that most Fe{sup 3+} occurs at the special crystallographic 24d position, which is the standard tetrahedrally coordinated site in garnet. Fe{sup 3+} in smaller

Evolution of Cygnus X-3 through its Radio and X-ray States

International Nuclear Information System (INIS)

Szostek, A.; Zdziarski, A. A.; McCollough, M. L.

2009-01-01

Based on X-ray spectra and studies of the long-term correlated behavior between radio and soft X-ray, we present a detailed evolution of Cyg X-3 through its radio and X-ray states. We comment on the nature of the hard X-ray tail and possible Simbol X contribution in constraining the models.

Evolution of Cygnus X-3 through its Radio and X-ray States

Science.gov (United States)

Szostek, A.; Zdziarski, A. A.; McCollough, M. L.

2009-05-01

Based on X-ray spectra and studies of the long-term correlated behavior between radio and soft X-ray, we present a detailed evolution of Cyg X-3 through its radio and X-ray states. We comment on the nature of the hard X-ray tail and possible Simbol X contribution in constraining the models.

The study of 3s3p4 configuration in the P-Sequence, Co X III - Ni X IV, by laser-produced plasmas

International Nuclear Information System (INIS)

Borges, F.O.; Cavalcanti, G.H.; Farias, E.E.; Trigueiros, A.G.

2007-01-01

Wavelengths from radiation of plasmas produced by a Nd:YAG/glass laser focused on target of Co and Ni have been recorded photographically in the region 240-600 A with a 3m normal incidence spectrograph. For this sequence (Co X III and Ni X IV) we have identified 13 new lines belonging to the array 3s 2 3p 3 -3s3p 4 and derived 7 new levels for the 3s3p 4 configuration. The classification was established by comparison of the relative intensities for the lines along the isoelectronic sequence, extrapolation, and Hartree-Fock calculation. (author)

Structural and physical properties of Mg3-xZnxSb2 (x=0-1.34)

International Nuclear Information System (INIS)

Ahmadpour, Faraz; Kolodiazhnyi, Taras; Mozharivskyj, Yurij

2007-01-01

The Mg 3-x Zn x Sb 2 phases with x=0-1.34 were prepared by direct reactions of the elements in tantalum tubes. According to the X-ray single crystal and powder diffraction, the Mg 3-x Zn x Sb 2 phases crystallize in the same P3-bar m1 space group as the parent Mg 3 Sb 2 phase. The Mg 3-x Zn x Sb 2 structure is different from the other substituted structures of Mg 3 Sb 2 , such as (Ca, Sr, Ba) Mg 2 Sb 2 or Mg 5.23 Sm 0.77 Sb 4 , in a way that in Mg 3-x Zn x Sb 2 the Mg atoms on the tetrahedral sites are replaced, while in the other structures Mg on the octahedral sites is replaced. Thermoelectric performance for the two members of the series, Mg 3 Sb 2 and Mg 2.36 Zn 0.64 Sb 2 , was evaluated from low to room temperatures through resistivity, Seebeck coefficient and thermal conductivity measurements. In contrast to Mg 3 Sb 2 which is a semiconductor, Mg 2.36 Zn 0.64 Sb 2 is metallic and exhibits an 18-times larger dimensionless figure-of-merit, ZT, at room temperature. However, thermoelectric performance of Mg 2.36 Zn 0.64 Sb 2 is still poor and it is mostly due to its large electrical resistivity. - Graphical abstract: The Mg atoms in Mg 3 Sb 2 were successfully substituted with Zn, with Zn going exclusively into the tetrahedral sites. Zn substitution increases the electrical conductivity in Mg 2.36 Zn 0.64 Sb 2 by closing the band gap. This change combined with a decrease in the thermal conductivity improves the ZT value

Growth and scintillation properties of Ce{sup 3+}-doped (Y{sub 1-x}Gd{sub x})AlO{sub 3} crystals

Energy Technology Data Exchange (ETDEWEB)

Fujimoto, Yutaka; Wakahara, Shingo; Suzuki, Shotaro; Kurosawa, Shunsuke [Institute of Materials Research, Tohoku University, 2-1-1 Katahira, Aoba-ku, Sendai, Miyagi 980-8577 (Japan); Yanagida, Takayuki [New Industry Creation Hatchery Center, Tohoku University, 6-6-10 Aramaki, Aoba-ku, Sendai 980-8579 (Japan); Yoshikawa, Akira [Institute of Materials Research, Tohoku University, 2-1-1 Katahira, Aoba-ku, Sendai, Miyagi 980-8577 (Japan); New Industry Creation Hatchery Center, Tohoku University, 6-6-10 Aramaki, Aoba-ku, Sendai 980-8579 (Japan)

2012-12-15

The optical and scintillation properties of 0.5% fixed Ce-doped (Y{sub 1-x}Gd{sub x})AlO{sub 3} single crystals have been investigated at three different levels of Gd doping: x = 0.2, 0.4 and 0.6. Single crystal of the Ce{sup 3+}-doped (Y{sub 0.8}Gd{sub 0.2})AlO{sub 3}, (Y{sub 0.6}Gd{sub 0.4})AlO{sub 3} and (Y{sub 0.4}Gd{sub 0.6})AlO{sub 3} were successfully grown by {mu}-PD technique in nitrogen atmosphere. From X-ray diffraction analysis, no impurity phase was detected for the grown Ce-doped crystals. Ce-doped (Y{sub 0.6}Gd{sub 0.4})AlO{sub 3} crystal demonstrated highest fluorescence quantum efficiency ({proportional_to} 25%) with improvement of excitation efficiency due to the Gd-doping. When irradiated by the alpha-rays from a {sup 241}Am source, all the Ce-doped crystals showed luminescence band that corresponding to 5d (t{sub 2g})-4f transition of Ce{sup 3+}. The scintillation decay time was characterized by two components; the fast component (5-15 ns) is ascribed to 5d-4f transition of Ce{sup 3+}, while the slow one (100-200 ns) may be related to energy transfer between Ce{sup 3+} and Gd{sup 3+} ion. According to the result of {sup 137}Cs gamma-ray irradiated pulse height spectra compared with BGO scintillator, the relative scintillation light output was found to be about 12200 {+-} 1220 (Gd 20%) and 16000 {+-} 1600 (Gd 40%) ph/MeV. (copyright 2012 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

Magnetoelastic effects in La{sub 0.7}Sr{sub 0.3−x}Ca{sub x}MnO{sub 3} nanocrystalline perovskites

Energy Technology Data Exchange (ETDEWEB)

Tabatabai Yazdi, Sh., E-mail: sh_tabatabai3@yahoo.com [Department of Physics, Faculty of Sciences, Ferdowsi University of Mashhad, Mashhad 91755-1436 (Iran, Islamic Republic of); Iranmanesh, P. [Department of Physics, Vali-e-Asr University of Rafsanjan, 77139-36417 Rafsanjan (Iran, Islamic Republic of)

2014-09-01

La{sub 0.7}Sr{sub 0.3−x}Ca{sub x}MnO{sub 3} (x=0, 0.1, 0.2 and 0.3) nanoparticles, prepared by sol–gel method, were studied by means of X-ray diffraction, transmission electron microscopy, thermal expansion and magnetostriction measurements. It was revealed that samples of low Ca concentration (x≤0.1) crystallize in rhombohedral perovskite structure with R-3c space group, and by increasing x, smaller Ca radius causes the lattice to convert to orthorhombic structure (space group of Pbnm). The results exhibit an anomalous behavior in the thermal expansion behavior of all samples, as well as temperature dependence of their volume magnetostriction being related to the presence of a conductive magnetic two-phase state at temperatures higher than T{sub C}. Moreover, the magnitude of this magnetovolume effect increases with x due to smaller Ca size, which softens the crystal lattice. The results show that Ca substitution results in weakening the double-exchange interaction and consequently reducing T{sub C}, as well as decreasing the magnetic anisotropy. Furthermore, our nanocrystalline samples have a relatively lower T{sub C}, compared with the reported values for similar compounds with larger particle size. Among them, the sample with x=0.2 possess T{sub C} value of about room temperature; to say by partial substitution of Ca for Sr we succeeded in adjusting the transition temperature of this series of manganites which was a main motivation for this research. - Highlights: • Magnetoelastic properties of La{sub 0.7}Sr{sub 0.3−x}Ca{sub x}MnO{sub 3} nanocrystalline samples are investigated. • Substitution of Sr by Ca causes structure to convert from rhombohedral to orthorhombic perovskite. • Considerable magnetovolume anomalies are revealed due to presence of conductive MTPS above T{sub C}. • Ca softens the crystal lattice and intensifies the magnetovolume effects. • Ca reduces T{sub C} and magnetic anisotropy of compounds by weakening DE interactions.

CHARACTERISTICS OF LITHIUM LANTHANUM TITANATE THIN FILMS MADE BY ELECTRON BEAM EVAPORATION FROM NANOSTRUCTURED La0.67-xLi 3xTiO3 TARGET

Directory of Open Access Journals (Sweden)

Nguyen Nang Dinh

2017-11-01

Full Text Available Bulk nanostructured perovskites of La0.67-xLi3xTiO3 (LLTO were prepared by using thermally ball-grinding from compounds of La2O3, Li2CO3 and TiO2. From XRD analysis, it was found that LTTO materials were crystallized with nano-size grains of an average size of 30 nm. The bulk ionic conductivity was found strongly dependent on the Li+ composition, the samples with x = 0.11 (corresponding to a La0.56Li0.33TiO3 compound have the best ionic conductivity, which is ca. 3.2 x 10-3 S/cm at room temperature. The LLTO amorphous films were made by electron beam deposition. At room temperature the smooth films have ionic conductivity of 3.5 x 10-5  S/cm and transmittance of 80%. The optical bandgap of the films was found to be of 2.3 eV. The results have shown that the perovskite La0.56Li0.33TiO3  thin films can be used for a transparent solid electrolyte in ionic battery and in all-solid-state electrochromic devices, in particular.

Highly constrained ferroelectric [BaTiO3](1−x)Λ/[BaZrO3]xΛ superlattices: X-ray diffraction and Raman spectroscopy

International Nuclear Information System (INIS)

Belhadi, J.; El Marssi, M.; Gagou, Y.; El Mendili, Y.; Bouyanfif, H.; Yuzyuk, Yu. I.; Raevski, I. P.; Wolfman, J.

2014-01-01

We report an x-ray diffraction (XRD) and a Raman-scattering investigation of ferroelectric/paraelectric superlattices [BaTiO 3 ] (1−x)Λ /[BaZrO 3 ] xΛ for which the composition varied, 0.15 ≤ x ≤ 0.85, while the superlattice (SL) modulation period Λ was kept constant at about 100 Å. The samples were epitaxially grown by pulsed laser deposition on MgO substrates buffered with La 0.5 Sr 0.5 CoO 3 . Based on the XRD analysis and on polarized Raman spectra, we have showed that the large strain in SLs induced ferroelectricity in BaZrO 3 (BZ) for all SLs, a material that is paraelectric in the bulk form at any temperature and in the single film. The induced polar axis in BZ layers is perpendicular to the plane of substrate while BaTiO 3 (BT) layers exhibit in-plane polar orientation. Raman spectroscopy revealed a lattice ordering in SLs due to the misfit strain generated by the large lattice mismatch between the alternating BZ and BT layers. This strain induced a huge upward frequency of the lowest E(1TO) soft mode from 60 cm −1 in the BT single film to 215 cm −1 in the SL with x = 0.85. These results show that in spite of relatively large periodicity of SLs, they are highly constrained and the variation of BZ ratio allowed modifying strains between layers. The temperature dependence of the Raman spectra for BT 0.3Λ /BZ 0.7Λ and BT 0.7Λ /BZ 0.3Λ samples revealed giant shift of the ferroelectric phase transition. The phase transition temperature was found to be upshifted by about 300 °C with respect to BT single crystal.

The O(α3s) Heavy Flavor Contributions to the Charged Current Structure Function xF3(x,Q2) at Large Momentum Transfer

International Nuclear Information System (INIS)

Behring, A.; Bluemlein, J.; Freitas, A. de; Johannes Kepler Univ., Linz; Hasselhuhn, A.; Manteuffel, A. von; Schneider, C.

2015-08-01

We calculate the massive Wilson coefficients for the heavy flavor contributions to the non-singlet charged current deep-inelastic scattering structure function xF W+ 3 (x,Q 2 )+xF W- 3 (x,Q 2 ) in the asymptotic region Q 2 >>m 2 to 3-loop order in Quantum Chromodynamics (QCD) at general values of the Mellin variable N and the momentum fraction x. Besides the heavy quark pair production also the single heavy flavor excitation s→c contributes. Numerical results are presented for the charm quark contributions and consequences on the Gross-Llewellyn Smith sum rule are discussed.

Bi[NC5H3(CO2)2](OH2)xF (x=1 and 2): New one-dimensional Bi-coordination materials—Reversible hydration and topotactic decomposition to α-Bi2O3

International Nuclear Information System (INIS)

Jeon, Hye Rim; Lee, Dong Woo; Ok, Kang Min

2012-01-01

Two one-dimensional bismuth-coordination materials, Bi[NC 5 H 3 (CO 2 ) 2 ](OH 2 ) x F (x=1 and 2), have been synthesized by hydrothermal reactions using Bi 2 O 3 , 2,6-NC 5 H 3 (CO 2 H) 2 , HF, and water at 180 °C. Structures of the two materials were determined by single-crystal X-ray diffraction. Although they have different crystal structures, both Bi-organic materials shared a common structural motif, a one-dimensional chain structure consisting of Bi 3+ cations and pyridine dicarboxylate linkers. Detailed structural analyses include infrared spectroscopy, thermogravimetric analysis, and reversible hydration reactions for the coordinated water molecules were reported. Also, thermal decomposition of the rod-shaped Bi[NC 5 H 3 (CO 2 ) 2 ](OH 2 )F single crystals at 800 °C led to α-Bi 2 O 3 that maintained the same morphology of the original crystals. - Graphical abstract: Calcination of the Bi[NC 5 H 3 (CO 2 ) 2 ](OH 2 )F single crystals at 800 °C results in the α-Bi 2 O 3 rods that maintain the original morphology of the crystals. Highlights: ► Synthesis of one-dimensional chain Bi-organic frameworks. ► Reversible hydration reactions of Bi[NC 5 H 3 (CO 2 ) 2 ](OH 2 )F. ► Topotactic decomposition maintaining the same morphology of the original crystals.

Optical properties of X-ray stars. 3

International Nuclear Information System (INIS)

Hudec, R.

1984-01-01

822 observations of X-ray system HZ Her/Her X-1 on Sonneberg sky-patrol-camera plates are interpreted with the following main results: (i) altogether 3 (and possibly 4) active and 3 (possibly 4) inactive states were revealed during the time span 1928 to 1979, (ii) the comparison of individual active-state light curves shows no clear differences, (iii) a very quick transition between active and inactive state JD 243 1313.382-JD 243 1321.403 was observed. Some other studies of the optical data were carried out and are briefly described. (author)

Conductividad eléctrica en corriente alterna de materiales cerámicos aurivillius de composición PbxBi4Ti3+xO12+3x, x=0,1,2 y 3

Directory of Open Access Journals (Sweden)

Moure, C.

2004-04-01

Full Text Available The ac electric conductivity of both textured and non textured Aurivillius ferroelectric ceramics PbxBi4Ti3+xO12+3x, where x = 0,1,2 and 3, has been studied by impedance measurements. The electrical conductivity decreases approximately one order of magnitude with the incorporation of a mol of lead titanate into the bismuth titanate structure. The anisotropy of the conductivity is kept between the ab plane and the c axis. The response seems to be related to the number of oxygen vacancies present in the crystalline structure of the materials, as well as to the aspect ratio of the grains. The activation energy values of the electrical conduction process are presented for both the ferroelectric and paraelectric phases.Se ha estudiado la conductividad eléctrica en corriente alterna (ca de la serie de materiales cerámicos ferroeléctricos con estructura Aurivillius: PbxBi4Ti3+xO12+3x, donde x = 0,1,2 y 3. El estudio se realiza a partir de la medida de la impedancia sobre muestras texturadas y no texturadas. La conductividad eléctrica disminuye sucesiva y aproximadamente en un orden de magnitud con el incremento sucesivo de un mol de titanato de plomo en la estructura del titanato de bismuto. Se mantiene la anisotropía de la conductividad entre el plano ab y el eje c de la estructura cristalina. La respuesta parece estar relacionada tanto con la variación del número de vacantes de oxígeno presentes en la estructura cristalina de los materiales, como con la variación de la relación de esbeltez de las placas que componen la microestructura de las muestras. Se presentan también los valores de energía de activación del proceso de conducción eléctrica en diferentes rangos de temperatura, tanto en la fase ferroeléctrica como en la paraeléctrica.

Static and dynamic magnetic properties of two synthetic francisites Cu3La(SeO3)2O2X (X = Br and Cl)

Science.gov (United States)

Markina, M. M.; Zakharov, K. V.; Zvereva, E. A.; Denisov, R. S.; Berdonosov, P. S.; Dolgikh, V. A.; Kuznetsova, E. S.; Olenev, A. V.; Vasiliev, A. N.

2017-04-01

The formation of long-range magnetic order at low temperatures was established in francisite—type compounds Cu3La(SeO3)2O2X (X = Br and Cl) through measurements of magnetic susceptibility, magnetization, specific heat and X-band electron spin resonance. The significantly enhanced critical index p = 1.0 ± 0.1 in Cu3La(SeO3)2Br and p = 0.8 ± 0.1 in Cu3La(SeO3)2Cl in the temperature dependence of the width of ESR signal evidence the reduced dimensionality of the kagome-type francisite's magnetic subsystem. Under action of external magnetic field, the presumably non-collinear six-sublattices antiferromagnetic structure of these compounds experiences the first-order metamagnetic transformation. The B- T magnetic phase diagrams were established from the positions of singularities in temperature and field dependences of thermodynamic properties. Contrary to pristine mineral Cu3Bi(SeO3)2Cl, no signature of structural phase transition was detected.

Al{sub 2}O{sub 3} reinforced nanoparticle ZrO{sub 2} (3at%?Y{sub 2}O{sub 3}); Al{sub 2}O{sub 3} reforcado com nanoparticulas de ZrO{sub 2}(3%mol Y{sub 2}O{sub 3})

Energy Technology Data Exchange (ETDEWEB)

Cossu, C.M.F.A.; Alves, M.F.R.P.; Campos, L.Q.B.; Magnago, R.O.; Santos, C., E-mail: caio.cossu@usp.br [Universidade do Estado do Rio de Janeiro (UERJ), Resende, RJ (Brazil). Faculdade de Tecnologia; Simba, B.G. [Universidade Estadual Paulista Julio de Mesquita Filho (UNESP), Guaratingueta, SP (Brazil). Faculdade de Engenharia

2016-07-01

This work developed a composite Al{sub 2}O{sub 3}-based reinforced with nanoparticles of ZrO{sub 2} (Y{sub 2}O{sub 3}), to evaluate the effect of the content of ZrO{sub 2} nanoparticles (Y{sub 2}O{sub 3}) on the mechanical properties. Mixtures containing a matrix of Al{sub 2}O{sub 3} with fractions in weight of 3%, 5%, 10% and 15%, ZrO{sub 2} (Y{sub 2}O{sub 3}), and were mixed in mortar mill. Mixtures received 5% polymeric binder (PVA); and after adding the binder, the material was pressed uniaxially to 50MPa, and then sintered at a temperature of 1600 ° C - 2h. The sintered products were characterized by X-ray diffraction, scanning electron microscopy (SEM), relative density, hardness and fracture toughness. The results of X-ray diffraction showed that Al{sub 2}O{sub 3} and tetragonal ZrO{sub 2} as crystal phases found after sintering. Furthermore, the relative green density of 55% was predominant in the compact; and after sintering, varied depending on the ZrO{sub 2} content, reaching 97% in sintered compositions with 3% ZrO{sub 2} nanoparticles (Y{sub 2O}3). The hardness of the samples showed values of 1670HV and the maximum toughness of 3.2 MPa × m{sup 1/2}, directly influenced by the presence of nanoparticles ZrO{sub 2} uniformly dispersed in the matrix Al{sub 2}O{sub 3}, which results in at least two main mechanisms tenacifiers: transformation of tetragonal-monoclinic phase of zirconia, and compressive residual strain between the two phases present, Al{sub 2}O{sub 3} and tetragonal ZrO{sub 2}. (author)

Cygnus X-3 and the problem of the missing Wolf-Rayet X-ray binaries

NARCIS (Netherlands)

Lommen, D.; Yungelson, L.; van den Heuvel, E.; Nelemans, G.A.; Portegies Zwart, S.

2005-01-01

Cygnus X-3 is a strong X-ray source (L_X ≈ 10³⁸ erg s^-1) which is thought to consist of a compact object accreting matter from a helium star. We analytically find that the estimated ranges of mass-loss rate and orbital-period derivative for Cyg X-3 are consistent

ThPt{sub 3+x}Be (x = 0.08): crystal structure and physical properties

Energy Technology Data Exchange (ETDEWEB)

Gumeniuk, Roman [Institut fuer Experimentelle Physik, TU Bergakademie Freiberg (Germany); Max-Planck-Institut fuer Chemische Physik fester Stoffe, Dresden (Germany); Kohout, Miroslav; Schnelle, Walter; Burkhardt, Ulrich; Leithe-Jasper, Andreas [Max-Planck-Institut fuer Chemische Physik fester Stoffe, Dresden (Germany); Zschornak, Matthias [Institut fuer Experimentelle Physik, TU Bergakademie Freiberg (Germany)

2017-01-03

ThPt{sub 3+x}Be (x = 0.08) is synthesized by arc melting of a mixture of the elements. It crystallizes with its own type of structure [space group I4/mmm (No. 139), a = 7.7370(4), c = 11.4990(6) Aa], which can be related to the cubic Ru{sub 3}Sn{sub 7} and W{sub 2}Cr{sub 21}C{sub 6} types. Measurements of magnetic susceptibility, electrical resistivity and specific heat indicate ThPt{sub 3+x}Be (x = 0.08) to be a diamagnet [χ{sub 0} = -9.0(3) x 10{sup -6} emu mol{sup -1}] with metallic electrical resistivity, in good agreement with the calculated electronic structure [N(E{sub F}) = 3.2 states eV{sup -1} f.u.{sup -1}]. A chemical bonding analysis was performed by the QTAIM and ELI-D approaches. (copyright 2017 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

Studies on electrical conduction behavior of La1-3xCaxBaxSrxMnO3 synthesized by chemical route

International Nuclear Information System (INIS)

Rai, A.K.; Parkash, O.; Mandal, K.D.

2008-01-01

In the manganite La 1-x M x MnO 3 (M=Ca,Ba,Sr) the doping concentration introduces a mixed valency (Mn 3+ , Mn 4+ ) which governs the magnetic and electrical properties of the compound. The perovskite oxides La 1-3x Ca x Ba x Sr x MnO 3 (x=0.00,0.05,0.10) were prepared by chemical method. Single-phase formation is confirmed by XRD studies. The electrical behavior of compositions with x=0.00, 0.05 and 0.10 in the system La 1-3x Ca x Ba x Sr x MnO 3 was studied in the temperature range 300-420 K. It is observed that conductivity decreases with increasing temperature as well as dopants concentration. Metallic behavior of these compositions decreases with increasing dopants concentration (x). The microstructures of these samples have been characterized using scanning electron microscopy (SEM). (copyright 2007 WILEY -VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

La5M3X (M=Sn, Bi; X=Cl, Br, I): exploring the limit of the Mn5Si3-type hosting lattice

International Nuclear Information System (INIS)

Zheng Chong; Mattausch, Hansjuergen; Simon, Arndt

2002-01-01

Three new compounds add to the family of the Mn 5 Si 3 type host-guest lattice. These are La 5 Sn 3 X (X=Cl, Br, I) synthesized from stoichiometric mixtures of La, LaX 3 and Sn heated under Ar atmosphere in sealed Ta ampoules at 850-990 deg. C for 13-62 days. La 5 Sn 3 X crystallize in the space group P6 3 /mcm (No. 193) with lattice parameters a=9.603(1) A, 9.637(1) A and 9.673(1) A; c=6.890(1) A, 6.931(1) A and 6.987(1) A, respectively, for X=Cl, Br and I. Computational analysis using both the extended Hueckel and the local density functional methods showed that the Sn and La site acts as electron reservoir, providing electrons to the interstitials as necessary. This gives rise to a metallic behavior. Susceptibility and conductivity measurements confirmed these predictions. The single crystal structure of La 5 Bi 3 Br is also reported

Dissociative electron attachment to methylhalides in 3-methylhexane glassy matrix

International Nuclear Information System (INIS)

Harada, K.; Irie, M.; Yoshida, H.

1976-01-01

Dissociative electron attachment reaction to CH 3 I, CH 3 Cl and CH 3 F in a 3-methylhexane glassy matrix was studied by determining the yield of trapped electrons and that of methyl radicals immediately after γ irradiation at 77 K as a function of the scavenger concentration. The efficiency of conversion from the trapped electrons to the methyl radicals was also studied by photobleaching the trapped electrons. The results obtained are (1) the dissociative electron attachment occurs to CH 3 F, for which the gas phase data indicate that the reaction is endothermic by 1.2 eV, during either the γ irradiation or the photobleaching, and (2) CH 3 F is relatively less efficient in scavenging photo-liberated electrons than in scavenging the electrons during the γ irradiation, whereas CH 3 I and CH 3 Cl are efficient scavengers for both the electrons. The dependence of the yields of the trapped electrons and the methyl radicals is discussed in terms of the electron-tunnelling mechanism and the epithermal electron-scavenging mechanism. (author)

Positron-annihilation study of oxygen-deficient YBa2Cu3Ox (6.3<x<6.9)

International Nuclear Information System (INIS)

Tang, C.Q.; Li, B.R.; Chen, A.

1990-01-01

We have measured the positron-lifetime spectra of oxygen-deficient YBa 2 Cu 3 O x for 6.3 m , τ 1 , τ 2 , and I 2 have a significant oxygen-content dependence. It is suggested that there are many kinds of positron states in polycrystalline YBa 2 Cu 3 O x , the disordering of O(1) vacancies strongly affects positron lifetime, and with gradually decreasing x the average electronic density decreases and the configuration and/or the charge states of the oxygen vacancies change in the region containing Cu(1)-O(1) chains

(1−x)[(K$_{0.5}$Na$_{0.5}$)NbO$_3$–LiSbO$_3

Indian Academy of Sciences (India)

Lead-free piezoelectric ceramics ( 1 − x ) [0.95(K 0.5 Na 0.5 )NbO 3 –0.05LiSbO 3 ]– x BiFe 0.8 Co 0.2 O 3 (KNN–LS– x BFC) were prepared by a conventional sintering technique. The effect of BFC content on the structure, piezoelectricand electrical properties of KNN–LS ceramics was investigated. The results reveal that ...

Synthesizing (ZrAl3 + AlN)/Mg-Al composites by a 'matrix exchange' method

Science.gov (United States)

Gao, Tong; Li, Zengqiang; Hu, Kaiqi; Han, Mengxia; Liu, Xiangfa

2018-06-01

A method named 'matrix exchange' to synthesize ZrAl3 and AlN reinforced Mg-Al composite was developed in this paper. By inserting Al-10ZrN master alloy into Mg matrix and reheating the cooled ingot to 550 °C, Al and Mg atoms diffuse to the opposite side. As a result, liquid melt occurs once the interface areas reach to proper compositions. Then dissolved Al atoms react with ZrN, leading to the in-situ formation of ZrAl3 and AlN particles, while the Al matrix is finally replaced by Mg. This study provides a new insight for preparing Mg composites.

Structure and magnetic transport properties of GdIn{sub 3−x}Mn{sub x} intermetallics

Energy Technology Data Exchange (ETDEWEB)

He, Qiang; Guo, Yongquan, E-mail: yqguo@ncepu.edu.cn; Liu, Hanyuan

2016-03-01

The crystal structures and magneto-transport properties of GdIn{sub 3−x}Mn{sub x} have been investigated using X-ray diffraction and magnetic and electric measurements. GdIn{sub 3−x}Mn{sub x} crystallize in cubic structure, and their lattice parameters tend to decrease with increasing Mn content due to the size effect at In site by Mn substitution for In. Mn doped GdIn{sub 3−x}Mn{sub x} order antiferromagnetically at low temperature. However, Mn doping into GdIn{sub 3} causes the decrease of Néel temperature due to the distortion of Gd(In,Mn){sub 3} tetrahedron formed by Gd at corners and (In,Mn) at face centers in unit cell. The resistivities of GdIn{sub 3−x}Mn{sub x} are going up with increasing Mn content. The electric phase transition is associated with the magnetic transition, and the magneto-transport follows electron–magnon scattering model in low temperature region and the Stoner spin fluctuation model in high temperature region, respectively. - Highlights: • Novel GdIn{sub 3−x}Mn{sub x} intermetallic compounds have been successfully prepared. • The lattice parameters tend to decrease with increasing Mn content. • GdIn{sub 3−x}Mn{sub x} orders antiferromagnetically at low temperature. • The strong correlation between the electric transport and magnetic state is observed.

Electronic structure of YbNiX{sub 3} (X =Si, Ge) studied by hard X-ray photoemission spectroscopy

Energy Technology Data Exchange (ETDEWEB)

Sato, Hitoshi; Shimada, Kenya; Namatame, Hirofumi [Hiroshima Synchrotron Radiation Center, Hiroshima University, Kagamiyama 2-313, Higashi-Hiroshima 739-0046 (Japan); Utsumi, Yuki [Max-Planck Institute for Chemical Physics of Solids, 01187 Dresden (Germany); Kodama, Junichi; Nagata, Heisuke [Graduate School of Science, Hiroshima University, Kagamiyama 1-3-1, Higashi-Hiroshima 739-8526 (Japan); Avila, Marcos A.; Ribeiro, Raquel A. [Centro de Ciencias Naturais e Humanas, Universidade Federal do ABC, Santo Andre - SP, 09210-580 (Brazil); Umeo, Kazunori [Cryogenics and Instrumental Analysis Division, N-BARD, Hiroshima University, Higashi-Hiroshima 739-8526 (Japan); Takabatake, Toshiro [Department of Quantum Matter, AdSM, Hiroshima University, Higashi-Hiroshima 739-8530 (Japan); Institute for Advanced Materials Research, Hiroshima University, Higashi-Hiroshima 739-8530 (Japan); Mimura, Kojiro; Motonami, Satoru; Anzai, Hiroaki [Graduate School of Engineering, Osaka Prefecture University, Sakai 599-8531 (Japan); Ueda, Shigenori [Synchrotron X-ray Station at SPring-8, National Institute for Materials Science, Hyogo 679-5148 (Japan); Taniguchi, Masaki [Hiroshima Synchrotron Radiation Center, Hiroshima University, Kagamiyama 2-313, Higashi-Hiroshima 739-0046 (Japan); Graduate School of Science, Hiroshima University, Kagamiyama 1-3-1, Higashi-Hiroshima 739-8526 (Japan)

2015-06-15

lectronic structure of the Kondo lattices YbNiX{sub 3} (X =Si, Ge) has been investigated by means of hard x-ray photoemission spectroscopy (HAXPES) with hν = 5.95 keV. From the Yb 3d HAXPES spectra, the Yb valence in YbNiSi{sub 3} is estimated to be ∝ 2.92, which is almost temperature-independent. On the other hand, the valence in YbNiGe{sub 3} is estimated to be 2.48 at 300 K, showing significant valence fluctuation, and gradually decreases to 2.41 at 20 K on cooling. The Ni 2p{sub 3/2} and Yb{sup 3+} 4f peaks exhibit opposite energy shifts amounting to ∝ 0.6 eV between YbNiSi{sub 3} and YbNiGe{sub 3}. We propose a simple model for the electronic structure of YbNiX{sub 3} based on the HAXPES results. (copyright 2015 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

Magnetic properties of Co 2 2+ Co 1 - x 3+ Fe x 3+ BO5 ( x = 0.10) single crystals with a ludwigite structure

Science.gov (United States)

Knyazev, Yu. V.; Kazak, N. V.; Bayukov, O. A.; Platunov, M. S.; Velikanov, D. A.; Bezmaternykh, L. N.; Ivanova, N. B.; Ovchinnikov, S. G.

2017-04-01

The investigation of mixed Co-Fe ludwigite single crystals shows that their magnetic properties are close to the magnetic properties of Fe3BO5 despite the predominance of cobalt ions. The magnetic properties of Co3 - x Fe x BO5 single crystals with x = 0.10 are studied in detail. Magnetometric measurements demonstrate a strong magnetic anisotropy with easy magnetization axis b, and the orbital magnetic moment of cobalt is in a frozen state. The detected temperature dependence of the absorption of Mössbauer spectra allowed us to determine the magnetic ordering temperature, which agrees with the results of magnetization measurements ( T C = 84 K).

The solubility and site preference of Fe3+ in Li7−3xFexLa3Zr2O12 garnets

International Nuclear Information System (INIS)

Rettenwander, D.; Geiger, C.A.; Tribus, M.; Tropper, P.; Wagner, R.; Tippelt, G.; Lottermoser, W.; Amthauer, G.

2015-01-01

A series of Fe 3+ -bearing Li 7 La 3 Zr 2 O 12 (LLZO) garnets was synthesized using solid-state synthesis methods. The synthetic products were characterized compositionally using electron microprobe analysis and inductively coupled plasma optical emission spectroscopy (ICP-OES) and structurally using X-ray powder diffraction and 57 Fe Mössbauer spectroscopy. A maximum of about 0.25 Fe 3+ pfu could be incorporated in Li 7−3x Fe x La 3 Zr 2 O 12 garnet solid solutions. At Fe 3+ concentrations lower than about 0.16 pfu, both tetragonal and cubic garnets were obtained in the synthesis experiments. X-ray powder diffraction analysis showed only a garnet phase for syntheses with starting materials having intended Fe 3+ contents lower than 0.52 Fe 3+ pfu. Back-scattered electron images made with an electron microprobe also showed no phase other than garnet for these compositions. The lattice parameter, a 0 , for all solid-solution garnets is similar with a value of a 0 ≈12.98 Å regardless of the amount of Fe 3+ . 57 Fe Mössbauer spectroscopic measurements indicate the presence of poorly- or nano-crystalline FeLaO 3 in syntheses with Fe 3+ contents greater than 0.16 Fe 3+ pfu. The composition of different phase pure Li 7−3x Fe x La 3 Zr 2 O 12 garnets, as determined by electron microprobe (Fe, La, Zr) and ICP-OES (Li) measurements, give Li 6.89 Fe 0.03 La 3.05 Zr 2.01 O 12 , Li 6.66 Fe 0.06 La 3.06 Zr 2.01 O 12 , Li 6.54 Fe 0.12 La 3.01 Zr 1.98 O 12 , and Li 6.19 Fe 0.19 La 3.02 Zr 2.04 O 12 . The 57 Fe Mössbauer spectrum of cubic Li 6.54 Fe 0.12 La 3.01 Zr 1.98 O 12 garnet indicates that most Fe 3+ occurs at the special crystallographic 24d position, which is the standard tetrahedrally coordinated site in garnet. Fe 3+ in smaller amounts occurs at a general 96h site, which is only present for certain Li-oxide garnets, and in Li 6.54 Fe 0.12 La 3.01 Zr 1.98 O 12 this Fe 3+ has a distorted 4-fold coordination. - Graphical abstract: Cubic nominally Li 7 La 3 Zr 2 O

(C2N2H10)[Fe xV1-x(HPO3)F3] (x = 0.44, 0.72): Two new organically templated phosphites

International Nuclear Information System (INIS)

Cisneros, Jose L.; Fernandez-Armas, Sergio; Mesa, Jose L.; Pizarro, Jose L.; Arriortua, Maria I.; Rojo, Teofilo

2006-01-01

(C 2 N 2 H 10 )[Fe x V 1-x (HPO 3 )F 3 ] (x = 0.44, 0.72) have been synthesized using mild solvothermal conditions under autogenous pressure and the ethylenediamine molecule as templating agent. The crystal structures have been determined from X-ray single-crystal diffraction data. The compounds crystallize in the orthorhombic P2 1 2 1 2 1 space group with Z = 4 and unit-cell parameters a = 12.8494(9), b = 9.5430(6), c = 6.4372(5) A, and a = 12.8578(1), b = 9.5342(1), c = 6.4370(7) A for (C 2 N 2 H 10 )[Fe 0.44 V 0.56 (HPO 3 )F 3 ] and (C 2 N 2 H 10 )[Fe 0.72 V 0.28 (HPO 3 )F 3 ] (1) and (2), respectively. These isostructural compounds exhibit a monodimensional crystal structure formed by pillared double anionic chains with the formula [M(HPO 3 )F 3 ] 2- , extended along the [0 0 1] direction. These doubled ionic chains are the result of the linking of two simple chains in which there are alternating octahedral [MO 3 F 3 ] and tetrahedral groups [HPO 3 ]. The ethylendiammonium cations are placed in the space delimited by three different chains. The metallic ions are interconnected by the pseudo-pyramidal (HPO 3 ) 2- phosphite oxoanions, adopting a slightly distorted octahedral geometry. The IR spectra show bands corresponding to the phosphite oxoanion and the ethylendiamonium cation at 2400 and 1600 cm -1 , respectively. The thermogravimetric analyses show that these phases are stable up to ca. 280 deg. C, at higher temperatures, the decomposition of the crystal structure begins by calcination of the organic cation and the elimination of the fluoride anions. The diffuse reflectance spectra show bands of the V 3+ ion (d 2 ) in octahedral symmetry. The values of the Dq (1540, 1540 cm -1 ), and Racah parameters, B (560, 535 cm -1 ) and C (3055, 3140 cm -1 ) for (1) and (2), respectively, correspond with those usually found for octahedrically coordinated V(III) compounds. Magnetic measurements, performed on a powered sample from 5.0 to 300 K at 1000 G, in the ZFC and