657,901 research outputs found
Anomalous Features in Surface Impedance of Y-Ba-Cu-O Thin Films: Dependence on Frequency, RF and DC Fields
Two high-quality Y-Ba-Cu-O thin films on MgO substrates have been
investigated using the coplanar resonator technique at 8 and 16 GHz. Both films
exhibit an anomalous decrease in their surface impedance, Zs as a function of
microwave field, Hrf. In zero dc field, Hrf-dependences of Rs and Xs for both
the samples are uncorrelated, and only one of the quantities, Rs or Xs,
displays anomalous behavior. Here, application of relatively weak (~5 mT) dc
magnetic fields, Hdc can produce a correlated decrease of Rs(Hrf) and Xs(Hrf).
The dependences of Zs on Hdc in both low and high microwave power regimes were
found to be non-monotonic. The frequency dependence of Rs ~ fn, 1.7<n<2.5,
remained the same upon the transition from low to high microwave power ranges.
The consequences of the reported findings for microwave device applications are
briefly discussedComment: 4 pages, 4 figures. Submitted to ASC'2000 Conference Proceeding
Vector Bosons in the Randall-Sundrum 2 and Lykken-Randall models and unparticles
Unparticle behavior is shown to be realized in the Randall-Sundrum 2 (RS 2)
and the Lykken-Randall (LR) brane scenarios when brane-localized Standard Model
currents are coupled to a massive vector field living in the five-dimensional
warped background of the RS 2 model. By the AdS/CFT dictionary these
backgrounds exhibit certain properties of the unparticle CFT at large N_c and
strong 't Hooft coupling. Within the RS 2 model we also examine and contrast in
detail the scalar and vector position-space correlators at intermediate and
large distances. Unitarity of brane-to-brane scattering amplitudes is seen to
imply a necessary and sufficient condition on the positivity of the bulk mass,
which leads to the well-known unitarity bound on vector operators in a CFT.Comment: 60 pages, 8 figure
Effect of a combination of enzymes on the fundamental rheological behavior of bread dough enriched with resistant starch
The effect of three enzymes on the fundamental rheological parameters of bread dough with high content of resistant starch (RS) was studied. The RS was added as an alternative to increase the fiber ingestion while the enzymes, to overcome the gluten dilution. Optimum dough was formulated with partial substitution of wheat flour by RS (12.5 g/100 g) and enzymes transglutaminase (4 mg/100 g), glucose oxidase (2.5 mg/100 g) and xylanase (0.5 mg/100 g). Dough produced with RS and without enzymes was considered as control and dough without RS or enzymes was considered as regular for comparison. Fundamental rheological parameters were obtained from uniaxial extension, biaxial extension and oscillatory tests. Also, starch gelatinization and retrogradation were studied by differential scanning calorimetry. The partial replacement of WF by RS resulted in less extensible dough, whereas the addition of enzymes increased the strain hardening index allowing higher dough expansion. The addition of enzymes reduced the elastic modulus resulting in a behavior similar to the regular dough. RS was not gelatinized during baking, hence it can be considered as dietetic fiber. Wheat starch retrogradation after 7 days of storage was observed, indicating bread aging.Fil: Altuna, Luz. Universidade de Sao Paulo; BrasilFil: Ribotta, Pablo Daniel. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto de Ciencia y Tecnología de Alimentos Córdoba. Universidad Nacional de Córdoba. Facultad de Ciencias Químicas. Instituto de Ciencia y Tecnología de Alimentos Córdoba; ArgentinaFil: Tadini, Carmen C.. Universidade de Sao Paulo; Brasi
A Decade Of Starspot Activity On The Eclipsing Short-Period RS Canum Venaticorum Star WY Cancri: 1988-1997
We present optical photometry of the short-period eclipsing RS CVn system WY Cancri for the years 1988–1997. For each light curve, we model the distortion waves in order to study the behavior of starspots in this system. After removing the spot effects f
A common behavior of thermoelectric layered cobaltites: incommensurate spin density wave states in [CaCoCuO][CoO] and [CaCoO][CoO]
Magnetism of a misfit layered cobaltite
[CaCoCuO][CoO] ( 0.62, RS
denotes a rocksalt-type block) was investigated by a positive muon spin
rotation and relaxation (SR) experiment. A transition to an
incommensurate ({\sf IC}) spin density wave ({\sf SDW}) state was found below
180 K (= ); and a clear oscillation due to a static
internal magnetic field was observed below 140 K (= ). Furthermore,
an anisotropic behavior of the zero-field SR experiment indicated that
the {\sf IC-SDW} propagates in the - plane, with oscillating moments
directed along the c axis. These results were quite similar to those for the
related compound [CaCoO][CoO], {\sl i.e.},
CaCoO. Since the {\sf IC-SDW} field in
[CaCoCuO][CoO] was approximately
same to those in pure and doped [CaCoO][CoO], it
was concluded that the {\sf IC-SDW} exist in the [CoO] planes.Comment: 15 pages, 6 figures. accepted for publication in J. Phys.: Condens.
Matte
Newton Law on the Generalized Singular Brane with and without 4d Induced Gravity
Newton law arising due to the gravity localized on the general singular brane
embedded in bulk is examined in the absence or presence of the 4d
induced Einstein term. For the RS brane, apart from the subleading correction,
Newton potential obeys 4d-type and -type gravitational law at long- and
short-ranges if it were not for the induced Einstein term. The 4d induced
Einstein term generates an intermediate range at short distance, in which the
Newton potential emerges. For Neumann brane the long-range
behavior of Newton potential is exponentially suppressed regardless of the
existence of the induced Einstein term. For Dirichlet brane the expression of
Newton potential is dependent on the renormalized coupling constant .
At particular value of Newton potential on Dirichlet brane exhibits a
similar behavior to that on RS brane. For other values the long-range behavior
of Newton potential is exponentially suppressed as that in Neumann brane.Comment: 27 pages, 2 postscript figures included V1 figures are improved and
few comments are added for further discussion. version to appear in NP
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