bluuebunny/crossref_metadata_2025_split huggingface dataset:
Effect of boron substitution on the crystallographic structure and superconducting properties in Y1‐xBxBa2Cu3Oy system
Authors: Mani D. K. , Zouaoui M. , Ben Azzouz F. , Annabi M. , Ben Salem M. 
Published: August 2006

AbstractThe changes in crystallographic and transport properties in the polycrystalline Y1‐xBxBa2Cu3Oy (YBBaCuO) compounds with x ranging from 0 to 0.55 have been investigated. Samples were synthesized using standard solid state reaction technique. The structure for all samples was characterized by X‐ray diffraction with Rietveld refinements technique. Their transport properties were measured by the standard four probe method in the temperature range from 20 to 300 K. The crystal lattice parameters are found to change due to the boron doping and YBBaCuO samples undergo to a structural phase transition from orthorhombic to tetragonal at x of more than 0.3. With the increase of x the transition temperature (Tconset) decreases. The dependence of resistivity on temperature, and the relation of the structural parameters versus the content of boron are discussed. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Magnetoelastic effects in the YFe10V2 ferromagnetic alloy
Authors: Khandan Fadafan H. , Alinejad M. R. , Tajabor N. , Fruchart D. , Gignoux D. 
Published: August 2006

AbstractMagnetoelastic effects in the YFe10V2 alloy between 5 and 300 K, and under magnetic fields up to 6 T are studied. Results show that spontaneous magnetostriction of the sample is positive in agreement with what is observed in similar iron based compounds and with the well known increase of the exchange interactions with interatomic distances. Two mechanisms of the forced magnetostriction, in polycrystalline samples, were clearly identified. The mechanism associated with the rotation of magnetization is of single ion origin and leads to a negative contribution to the volume magnetostriction. The other mechanism, mainly of two ions origin, is the same as the one responsible for the spontaneous magnetostriction. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Effect of temperature on the electronic structure in n‐modulation‐doped AlxGa(1–x)As/GaAs heterostructure
Authors: Dakhlaoui H. , Jaziri S. 
Published: August 2006

AbstractWe theoretically study the subband structure of n‐modulation‐doped AlxGa(1–x)As/GaAs heterostructure using a self‐consistent procedure to solve simultaneously the Schrödinger and Poisson equations. Our results show that the sheet electron concentration can be modified by both increasing the temperature and the spacer thickness. The results also indicate that the energy levels are not prolonged linearly as the temperature increases but show step‐like behavior. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Lattice dynamics and the electromechanical properties of BaTiO3 in tetragonal phase
Authors: Khalal Ali , Khatib Driss 
Published: August 2006

AbstractA lattice dynamical formalism using the shell model (R. A. Cowley, Phys. Rev. 134, A981 (1964) [1]) is applied to ferroelectric crystal BaTiO3, in the tetragonal phase. This microscopic model includes the short‐range interactions of axially symmetric type and the long‐range Coulomb interactions takes into account the electronic polarizability of constituent ions. The stability conditions of crystal are used to determine several first‐derivatives potential for the crystals. Zone center phonons are used for fitting. In general, we obtained the best agreement between the calculated and observed frequencies. A calculation of the oblique phonons and electromechanical coupling are presented and compared with the available experimental data. It can be seen that, the electromechanical coupling is at a maximum when the acoustic wave is polarized parallel to the polar c‐axis, and there is zero coupling when the polarization is perpendicular to this axis. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Preparation of nano‐sized manganese ferrite (MnFe2O4) via coprecipitation method
Authors: Amighian J. , Mozaffari M. , Nasr B. 
Published: August 2006

AbstractNano‐sized manganese ferrite (MnFe2O4) powder has been synthesized via coprecipitation method, using FeSO4·7H2O and MnSO4·H2O as starting materials. An aqueous solution of the starting materials, containing Fe2+ and Mn2+ in the ratio required in the ferrite, was poured into an NaOH alkaline solution. A greenish precipitate was formed, which carefully washed and dried for 6 h at 80 °C. The dried powder was then heated for 2 h at different temperatures in argon atmosphere and then rapidly cooled to room temperature, using water quenching. XRD patterns of the samples show that the sample annealed at 1050 °C is single phase. Also using Scherrer's formula a mean crystallite size of 80 nm was obtained. Magnetic measurements were performed on cold pressed pellets, using a sensitive permeameter with a maximum field of 1.2 T. The results show that a single phase MnFe2O4 nano‐sized powder can be obtained at annealing temperature of 1050 °C, which is lower than 1250 °C related to the annealing temperature of the same ferrite, prepared by the conventional ceramic technique. Saturation magnetization of the single‐phase sample was 1330 G, which is lower than 5000 G related to a bulk sample. The difference between the values is reasonable, because the magnetic measurements were performed on cold‐pressed unsintered nano sized powders. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Evidence of non‐linear to linear transformation of the normal state resistivity in YBCO at constant oxygen content
Authors: Abdelhadi M. M. 
Published: August 2006

AbstractWe studied the origin of variation in the magnitude and temperature dependence of the normal state resistivity frequently observed in different Y Ba2Cu3O7–δ (YBCO) single crystal or thin film samples with the same T C. We investigated the temperature dependence of resistivity in YBCO thin films, which were subjected to annealing in argon at 120 – 140 °C or aging at room temperature in air. Before annealing (or aging) these films exhibited a non‐linear in‐plane resistivity ρ a b (T), with upward deviation (flattening) in ρ a b (T) from the linear high temperature behavior below 220‐230 K. For all films the annealing causes an increase of resistivity and a transformation of ρ a b (T) from a non‐linear dependence towards a more linear one (less flattening). Our proposed model provides explanation of these phenomena based on the thermally activated redistribution of residual O(5) oxygen in the chain‐layer of YBCO without any change in the overall oxygen content within the sample. The results show that a perfectly linear ρ (T) can be observed in YBCO of oxygen content 7 – δ as low as 6.8. The agreement between the our data for ρ a b (T; t) and the proposed model was very good. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Remanent magnetization of Fe1–xCox fine particles
Authors: Sebt S. A. , Zoriasatain S. , Akhavan M. 
Published: August 2006

AbstractFine Fe1–xCox grains with various values of x have been grown via the borohydride method in the presence of different magnetic fields, H0. In this method, the presence of magnetic moments at the bcc lattice sites of iron causes the formation of acicular single domain grains with a nearly 0.2 μm length. The magnetic field, H0, sets the magnetic moment of SD grains parallel to each other and forms some chains of these particles. This is equivalent to the presence of an effective internal field that increases the remanent magnetization, Mr. From the SW model point of view, the remanent magnetization of sample is determined by Boltzman distribution function at the two minimum energies. In fact, it is the thermal fluctuation that is responsible for the reduction of remanent magnetization. Therefore, in addition to the coercivity effect, the presence of an effective internal field also increases the Mr. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
The influence of magnetic field on the stability region of the bipolaron in high‐Tc superconductors with the Van Hove scenario
Authors: Bouayad M. , El Amrani B. , Fliyou M. , Chaouch M. 
Published: August 2006

AbstractThe properties of polarons and bipolarons are studied by the variational method taking into account the density of state for Van Hove singularity (V.H.S) in two‐dimension (2D) in the presence of a perpendicular magnetic field. It should be noticed that the bipolaron stability region is relatively sensitive to the application of a magnetic field. In 2D, for ωc = 0.8 the value of αc = 1 is compared to αc = 1.6 for ωc = 0. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Anisotropic effects in a powder oriented YBCO sample using a three axes magnetometer
Authors: Boudissa M. , Halimi R. , Senoussi S. 
Published: August 2006

AbstractTo measure the components of the magnetization vector along the XYZ directions of a reference frame, in the superconducting materials, we have conceived a three axes magnetometer, with a detection system equipped with three series of pick‐up coils with axes parallel to the three directions X,Y, and Z. We describe in this paper the details of the design and the method of measurement, with some results obtained by magnetic measurements on samples of oriented YBCO powder, with size of the grains between 20 µm and 40 µm, for values of the angle θ between the magnetic field H and the c‐axis, between 0° and 90° and for values of fields up to 12 T. The direct measurement of the Z and the XY components of the irreversible magnetization vector, Mirr, allowed us to observe the twin effect (channeling) on the vortex pinning observed by many authors, the evolution of the magnetization vector and to measure with a high accuracy the anisotropy factor of our samples. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Analysis of the noise voltage in high‐Tc superconducting thin films
Authors: Labrag A. , Bghour M. , Abaragh A. , Bouaaddi A. , Ramzi A. , Taoufik A. , Senoussi S. , Tirbiyine A. 
Published: August 2006

AbstractWe measured the noise spectral density SV variations of YBa2Cu3O7–δ films in a large range of frequencies f 0.1‐1000 Hz, temperature T and under the effect of a magnetic field up to 14 T. in order to clarify the origin of the noise observed in thin films deposed by the laser ablation method on the surface (001) of SrTiO3 substrate, the noise power spectral density S(f,T) of the noise variations versus temperature and frequency is presented in Fig. 3 for H = 14 T parallel to the ab plane, I = 3 nA. We can observe from this result that the noise spectral density SV(T) shows a marked enhancement near Tc the temperature superconducting transition. Our results suggested that the main source for the noise in the mixed state is the thermally activated vortex motion in the high‐Tc superconducting thin films. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Effects of Zn doping on YBaCuO superconductor
Authors: Mahtali M. , Chamekh S. , Boucherka T. , Bouabellou A. 
Published: August 2006

AbstractIn this work we present a study of Zn impurity effects on the YBa2Cu3O7–δ high Tc superconducting ceramics prepared by the solid state reaction method. X‐ray diffraction (XRD), scanning electron microscopy (SEM) and differential thermal analysis (DTA) techniques, and resistivity measurements are used to characterize the YBa(Cu1–xZnx)3O7–δ samples. The obtained results show that, for example, the value of the transition critical temperature is decreasing up to 80 K caused by the substitution of Zn for Cu in the interval 0 ≤ x ≤ 0.01. Also, the peritectic transformation of superconducting phase undergoes a displacement to lower temperatures compared with pure YBaCuO. On the basis of the obtained results, the effects of Zn doping on the structural and electronic properties are explained. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Formation of the magnetization loops of high‐Tc superconductors
Authors: Abaragh A. , Taoufik A. , Ramzi A. , Senoussi S. , Labrag A. , Bghour M. , Bouaaddi A. , Tirbiyine A. 
Published: August 2006

AbstractWe have investigated the irreversibility magnetic field and the critical current density of the high temperature superconductor YBa2Cu3O7–δ single crystal. Vibrating sample magnetometer (V.S.M.) method was used for these measurements. Magnetization hysteresis loops scale and shape are strongly dependent on the temperature values and the angle θ between the direction of the applied magnetic field and c‐axis. For the large single crystals at very low temperature the loops present several flux jumps “saw‐tooth” and we observe the second peak “fish‐tail” for high temperature values but not with applied magnetic field perpendicular to the ab ‐planes. Beyond θ = 30°, the irreversibility field Hirr increases deviates from different temperature values. The variation of the critical current density Jc with applied magnetic field parallel to c‐axis for different temperatures was studied. Here, Jc is an effective critical current density deduced from the measured magnetization by the Bean formula. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Hormonal and Stress Induction of the Gene Encoding Common Bean Acetyl-Coenzyme A Carboxylase
Authors: Figueroa-Balderas Rosa Elia , García-Ponce Berenice , Rocha-Sosa Mario 
Published: August 2006

Abstract
Regulation of the cytosolic acetyl-coenzyme A carboxylase (ACCase) gene promoter from common bean (Phaseolus vulgaris) was studied in transgenic Arabidopsis (Arabidopsis thaliana) plants using a β-glucuronidase (GUS) reporter gene fusion (PvACCase∷GUS). Under normal growth conditions, GUS was expressed in hydathodes, stipules, trichome bases, flowers, pollen, and embryos. In roots, expression was observed in the tip, elongation zone, hypocotyl-root transition zone, and lateral root primordia. The PvACCase promoter was induced by wounding, Pseudomonas syringae infection, hydrogen peroxide, jasmonic acid (JA), ethylene, or auxin treatment. Analysis of PvACCase∷GUS expression in JA and ethylene mutants (coronatine insensitive1-1 [coi1-1], ethylene resistant1-1 [etr1-1], coi1-1/etr1-1) suggests that neither JA nor ethylene perception participates in the activation of this gene in response to wounding, although each of these independent signaling pathways is sufficient for pathogen or hydrogen peroxide-induced PvACCase gene expression. We propose a model involving different pathways of PvACCase gene activation in response to stress.
Rapid Metabolism of Glucose Detected with FRET Glucose Nanosensors in Epidermal Cells and Intact Roots of Arabidopsis RNA-Silencing Mutants
Authors: Deuschle Karen , Chaudhuri Bhavna , Okumoto Sakiko , Lager Ida , Lalonde Sylvie , Frommer Wolf B. 
Published: August 2006

Abstract
Genetically encoded glucose nanosensors have been used to measure steady state glucose levels in mammalian cytosol, nuclei, and endoplasmic reticulum. Unfortunately, the same nanosensors in Arabidopsis thaliana transformants manifested transgene silencing and undetectable fluorescence resonance energy transfer changes. Expressing nanosensors in sgs3 and rdr6 transgene silencing mutants eliminated silencing and resulted in high fluorescence levels. To measure glucose changes over a wide range (nanomolar to millimolar), nanosensors with higher signal-to-noise ratios were expressed in these mutants. Perfusion of leaf epidermis with glucose led to concentration-dependent ratio changes for nanosensors with in vitro K d values of 600 μM (FLIPglu-600μΔ13) and 3.2 mM (FLIPglu-3.2mΔ13), but one with 170 nM K d (FLIPglu-170nΔ13) showed no response. In intact roots, FLIPglu-3.2mΔ13 gave no response, whereas FLIPglu-600μΔ13, FLIPglu-2μΔ13, and FLIPglu-170nΔ13 all responded to glucose. These results demonstrate that cytosolic steady state glucose levels depend on external supply in both leaves and roots, but under the conditions tested they are lower in root versus epidermal and guard cells. Without photosynthesis and external supply, cytosolic glucose can decrease to &lt;90 nM in root cells. Thus, observed gradients are steeper than expected, and steady state levels do not appear subject to tight homeostatic control. Nanosensor-expressing plants can be used to assess glucose flux differences between cells, invertase-mediated sucrose hydrolysis in vivo, delivery of assimilates to roots, and glucose flux in mutants affected in sugar transport, metabolism, and signaling.
Lipolytic Activity of Microorganisms at Low and Intermediate Temperatures. II. Fatty Acids Released As Determined by Gas Chromatography
Authors: ALFORD JOHN A. , ELLIOTT L. E. , HORNSTEIN IRWIN , CROWE P. F. 
Published: August 2006

SUMMARYDetermination was made of the types and quantities of fatty acids released from lard, tallow, corn oil, and coconut oil by lipases from psychrophilic strains of Pseudomonas. The fatty acids were measured by gas chromatography. The rate of fatty acid liberation fell off sharply after the first few hours, but the ratios of the types of fatty acids were not affected until after 24 hours. Additional evidence is presented that much of the palmitic acid in lard is esterified at the beta position. Also discussed is the possible effect of differences in rate of lipolysis of fatty acids from natural substrates on interpretation of their degree of randomness, as measured by enzyme specificity.
The Nutritive Value of Maine Sardines.a
Authors: PROCTOR B. E. , MILLER S. A. , GOLDBLITH S. A. , WICK E. L. , PARTSER E. R. , SAPERS G. M. , SOLBERG M. 
Published: August 2006

SUMMARYMaine sardines, processed by steaming or deep‐fat frying, were evaluated in terms of a number of nutrients. The product is a good source of a number of nutrients, including protein, unsaturated fatty acids, fluorine, and calcium. Some indication was found of an exchange between the packing oil and sardine lipid. The sample processed by deep‐fat frying had a slightly increased fat concentration and a concomitant decrease in water.
Maple Sirup. XVI. Isolation and Identification of Compounds Contributing to the Flavor of Maple Sirupa
Authors: UNDERWOOD J. C. , WILLITS C. O. , LENTO HARRY G. 
Published: August 2006

SUMMARYA major portion of the flavor was isolated from maple sirup by extraction with chloroform. From this was separated several pure crystalline compounds and several impure materials. Vanillin and syringaldehyde were definitely identified. These are compounds that could come from precursors in the decomposition of lignin, and this possible source of maple flavor is being investigated.
Spectrophotometric Determination of Sorbic Acid in Apple Cidera
Authors: HARRINGTON W. O. , JAHN ANNE S. , HILLS CLAUDE H. 
Published: August 2006

SUMMARYAn improved method for measuring sorbic acid in cider is based on dilution of the sample and direct ultraviolet readings at 262 mμ This method was compared with the distillation method for sorbic acid usually applied to cider. The latter method produced ultraviolet‐absorbant materials that interfered with sorbic acid determinations and were shown to he affected by the sugar content of the cider and the distillation techniques. The ultraviolet‐interfering materials in cider distillates have absorption peaks and chemical properties similar to those of 5‐hydroxymethylfurfural.
An Ion‐Exchange Study of the Free Amino Acids in the Juices of Six Varieties of Citrusa
Authors: CLEMENTS ROBERT L. , LELAND HARRY V. 
Published: August 2006

SUMMARYFree amino acids were determined in the juices of mature Valencia and Washington navel oranges, Eureka and Lisbon lemons, Dancy taugerines, and Marsh grapefruit. Twelve amino acids and ammonia were identified and measured quantitatively. Eleven unidentified ninhydrin‐positive compounds were also'detected. Alanine, asparagine, aspartic acid, glutamic acid, proline, set‐me, γ‐aminobutyric acid, and arginine occurred in substantial amounts in all fruits. Proline was the most prominent amino acid in every fruit except the grapefruit, hut appeared in especially high concentrations in the Valencia orange. Aspartic acid predominated in the grapefruit. Nitrogen calculated from the amino acids accounted for approximately 70% of the Kjeldahl nitrogen in each of the juices.
Some Relations Between the Chemical and Physical Characteristics of Bovine Muscles
Authors: LOCKETT C. , SWIFT C. E. , SULZBACHER W. L. 
Published: August 2006

SUMMARYVariations in the distribution of water in bovine muscles were investigated with histological and chemical analyses. A histological method has been developed to measure the extracellular space. This property, along with water and protein content and pH values, was determined in four muscles from each of four animals. The results indicate that extracellular space varied among the muscles of the animals according to a definite pattern. Among the relations found, extracellular space was positively correlated with the water‐protein ratio, whereas intracellular water content was negatively correlated. The evidence indicates that, in the muscles that characteristically contain a relatively high proportion of water to protein, the additional water is located in extracellular spaces.
Studies on the Fate of Staphylococci During the Processing of Hams
Authors: SILLIKER J. H. , JANSEN C. E. , VOEGELL M. M. , CHMURA N. W. 
Published: August 2006

SUMMARYStaphylococci are destroyed during the heat processing of both smoked and fully cooked hams. Although these organisms are capable of growth in the presence of sodium chloride, sodium nitrate, and sodium nitrite in the concentrations used in cored meats, they are readily destroyed in the presence, as well as the absence, of these agents at a temperature of 137° F. Twenty‐two of 53 strains of Staphylococcus aureus were killed in excess of 99% after 10 min exposure at this temperature. Thirty‐one strains exhibited more resistance, but were destroyed in excess of 99.9% after 60 min at 137°F. The significance of these results in terms of previous studies is discussed.
Iron and the Bacterial Spoilage of Shell Eggs
Authors: GARIBALDI J. A. , BAYNE H. G. 
Published: August 2006

SUMMARYThe finding that iron has a profound effect in increasing both the rate and extent of Pseudomonas spoilage of experimentally infected shell eggs was extended to other egg spoilage bacteria. All bacteria tested were so affected. These gram‐negative bacteria included five strains of Proteus, three of Paracolobactrum, two of Alcaligenes, two of Aerobacter, two of Achromobacter, and two of Salmonella.
Quantitative Aspects of the Interaction of Carrageenan with Cationic Substances
Authors: GRAHAM HORACE D. , THOMAS LINNIE B. 
Published: August 2006

SUMMARYUsing the interaction of carrageenan (Seakem type 5) with cetylpyridinium chloride as the type example, investigation was made of optimum conditions for the precipitation of carrageenan and its fractions by quaternary ammonium detergents. Found to be very critical factors for quantitative precipitation were the temperature and pH of the reaction medium. Comparatively, the amount of detergent cation bound by a particular sulfated hydrocolloid is indicative of its degree of sulfation.
Biochemical Changes in Fish Muscle During Rigor Mortis
Authors: NAZIR D. J. , MAGAR N. G. 
Published: August 2006

SUMMARYMullets (Mugil dussumieri), Bombay ducks (Harpodon nehereus), and groupers (Epinephalus malabaricus) were stored in crushed ice at about 2°C, and changes in pH, glycogen, lactic acid, inorganic phosphorus, creatine phosphate, ATP, acid‐soluble and Ba‐acetate non‐precipitable ribose, and TMA were studied. Though glycogen decreased and lactic acid increased throughout, no direct relation was observed, and measurable quantities of glycogen were present at the end of the experiment. Inorganic phosphorus increased slowly, and creatine phosphate and ATP decreased, the former at a more rapid rate. The Ba‐acetate non‐precipitable ribose and the ratio of non‐precipitable ribose to acid‐soluble ribose increased continuously. TMA values rose slowly, but were quite low even at the end of the experiment.