3,685 research outputs found
Entropy Change through Rayleigh-B\'enard Convective Transition with Rigid Boundaries
The previous investigation on Rayleigh-B\'enard convection of a dilute
classical gas [T. Kita: J. Phys. Soc. Jpn. {\bf 75} (2006) 124005] is extended
to calculate entropy change of the convective transition with the rigid
boundaries. We obtain results qualitatively similar to those of the stress-free
boundaries. Above the critical Rayleigh number, the roll convection is realized
among possible steady states with periodic structures, carrying the highest
entropy as a function of macroscopic mechanical variables.Comment: 5 pages, 4 figure
A theory of new type of heavy-electron superconductivity in PrOs_4Sb_12: quadrupolar-fluctuation mediated odd-parity pairings
It is shown that unconventional nature of superconducting state of
PrOs_4Sb_12, a Pr-based heavy electron compound with the filled-Skutterudite
structure, can be explained in a unified way by taking into account the
structure of the crystalline-electric-field (CEF) level, the shape of the Fermi
surface determined by the band structure calculation, and a picture of the
quasiparticles in f-configuration with magnetically singlet CEF ground
state. Possible types of pairing are narrowed down by consulting recent
experimental results. In particular, the chiral "p"-wave states such as
p_x+ip_y is favoured under the magnetic field due to the orbital Zeeman effect,
while the "p"-wave states with two-fold symmetery such as p_x can be stabilized
by a feedback effect without the magnetic field. It is also discussed that the
double superconducting transition without the magnetic field is possible due to
the spin-orbit coupling of the "triplet" Cooper pairs in the chiral state.Comment: 12 pages, 2 figures, submitted to J. Phys.: Condens. Matter Lette
Theory of Flux-Flow Resistivity near for s-wave Type-II Superconductors
This paper presents a microscopic calculation of the flux-flow resistivity
for s-wave type-II superconductors with arbitrary impurity
concentrations near the upper critical field . It is found that, as the
mean free path becomes longer, increases gradually from the
dirty-limit result of Thompson [Phys. Rev. B{\bf 1}, 327 (1970)] and Takayama
and Ebisawa [Prog. Theor. Phys. {\bf 44}, 1450 (1970)]. The limiting behaviors
suggest that at low temperatures may change from convex downward
to upward as increases, thus deviating substantially from the linear
dependence predicted by the Bardeen-Stephen theory
[Phys. Rev. {\bf 140}, A1197 (1965)]
Ozone-enhanced layers in the troposphere over the equatorial Pacific Ocean and the influence of transport of midlatitude UT/LS air
International audienceOccurrence of ozone (O3)-enhanced layers in the troposphere over the equatorial Pacific Ocean and their seasonal variation were investigated based on ozonesonde data obtained at three Southern Hemisphere ADditional OZonesondes (SHADOZ) sites, Watukosek, American Samoa and San Cristobal, for 6 years between 1998 and 2003. O3-enhanced layers were found in about 50% of observed O3 profiles at the three sites on yearly average. The formation processes of O3-enhanced layers were investigated by meteorological analyses including backward trajectories. On numerous occasions, O3-enhanced layers resulted from the transport of air masses affected by biomass burning. The contribution of this process was about 30% at San Cristobal during the periods from February to March and from August to September, while it was relatively low, about 10%, at Watukosek and Samoa. A significant number of the O3-enhanced layers were attributed to the transport of midlatitude upper-troposphere and lower-stratosphere (UT/LS) air. Meteorological analyses indicated that these layers originated from equatorward and downward transport of the midlatitude UT/LS air masses through a narrow region between high- and low-pressure systems around the subtropical jet stream. This process accounted for more than 40% at Watukosek between May and December, about 60% or more at Samoa all year around, and about 40% at San Cristobal between November and March, indicating that it was important for O3 budget over the equatorial Pacific Ocean
Ensiling Characteristics of Sudangrass Silage Treated with Green Tea Leaf Waste or Green Tea Polyphenols
Green tea waste (GTW), emitted from beverage companies manufacturing tea drinks, contains high crude protein (CP) and polyphenols. Kondo et al. (2004) showed that GTW addition to forage ensiling enhanced lactic acid fermentation and decreased pH value. Ishihara et al. (2001) showed that high counts of Lactobacillus species were maintained and the counts of clostridia were decreased in the intestinal microflora of animals fed the diet containing green tea polyphenols (GTP). It is hypothesised that GTP might activate lactic acid bacteria and enhance silage fermentation. This study was conducted to evaluate the potential of GTW and GTP as silage additives and explored the mechanisms of enhanced lactic acid fermentation by GTW
Fermentation Characteristics of Maize/Sesbania Bi-Crop Silage
Maize is one of the main forages for dairy production and is a suitable material for silage making because of high fermentable carbohydrates, high counts of lactic acid bacteria (LAB) and low buffering capacity (BC) (Nishino et al. 2003; McDonald et al. 1991). Whole crop maize silage is high in energy but low in crude protein (CP). On the other hand, legumes are high in CP but difficult to conserve because of their low water soluble carbohydrates (WSC) and high BC. It might be possible that maize/legume bi-crop silage compensate for their negative points. Sesbania is a legume originated in tropical area and might be suitable for inter-crops with maize. Therefore, we investigated the fermentation characteristics of bi-crop silage from maize and sesbania
Quasiparticles of d-wave superconductors in finite magnetic fields
We study quasiparticles of d-wave superconductors in the vortex lattice by
self-consistently solving the Bogoliubov-de Gennes equations. It is found for a
pure state that: (i) low-energy quasiparticle bands in the
magnetic Brillouin zone have rather large dispersion even in low magnetic
fields, indicating absense of bound states for an isolated vortex; (ii) in
finite fields with small, the calculated tunneling conductance at
the vortex core shows a double-peak structure near zero bias, as qualitatively
consistent with the STM experiment by Maggio-Aprile et al. [Phys. Rev. Lett.
{\bf 75} (1995) 2754]. We also find that mixing of a - or an s-wave
component, if any, develops gradually without transitions as the field is
increased, having little effect on the tunneling spectra.Comment: 4 pages, 4 figures, LaTe
Entropy and Spin Susceptibility of s-wave Type-II Superconductors near
A theoretical study is performed on the entropy and the spin
susceptibility near the upper critical field of s-wave
type-II superconductors with arbitrary impurity concentrations. The changes of
these quantities through may be expressed as , for example, where is the average flux density
and denotes entropy in the normal state. It is found that the
slopes and at T=0 are identical, connected
directly with the zero-energy density of states, and vary from 1.72 in the
dirty limit to in the clean limit. This mean-free-path dependence
of and at T=0 is quantitatively the same as that
of the slope for the flux-flow resistivity studied
previously. The result suggests that and near
T=0 are convex downward (upward) in the dirty (clean) limit, deviating
substantially from the linear behavior . The specific-heat
jump at also shows fairly large mean-free-path dependence.Comment: 8 pages, 5 figure
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