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51.
Heqing Jiang Dr. Fangyi Liang Oliver Czuprat Konstantin Efimov Armin Feldhoff Dr. Steffen Schirrmeister Dr. Thomas Schiestel Dr. Haihui Wang Prof. Jürgen Caro Prof. 《Chemistry (Weinheim an der Bergstrasse, Germany)》2010,16(26):7898-7903
A porous perovskite BaCoxFeyZr0.9?x?yPd0.1O3?δ (BCFZ‐Pd) coating was deposited onto the outer surface of a BaCoxFeyZr1?x?yO3?δ (BCFZ) perovskite hollow‐fiber membrane. The surface morphology of the modified BCFZ fiber was characterized by scanning electron microscopy (SEM), indicating the formation of a BCFZ‐Pd porous layer on the outer surface of a dense BCFZ hollow‐fiber membrane. The oxygen permeation flux of the BCFZ membrane with a BCFZ‐Pd porous layer increased 3.5 times more than that of the blank BCFZ membrane when feeding reactive CH4 onto the permeation side of the membrane. The blank BCFZ membrane and surface‐modified BCFZ membrane were used as reactors to shift the equilibrium of thermal water dissociation for hydrogen production because they allow the selective removal of the produced oxygen from the water dissociation system. It was found that the hydrogen production rate increased from 0.7 to 2.1 mL H2 min?1 cm?2 at 950 °C after depositing a BCFZ‐Pd porous layer onto the BCFZ membrane. 相似文献
52.
Simard P Lace N Gowans S Quintana-Rizzo E Kuczaj SA Wells RS Mann DA 《The Journal of the Acoustical Society of America》2011,130(5):3068-3076
Dolphins routinely use sound for social purposes, foraging and navigating. These sounds are most commonly classified as whistles (tonal, frequency modulated, typical frequencies 5-10 kHz) or clicks (impulsed and mostly ultrasonic). However, some low frequency sounds have been documented in several species of dolphins. Low frequency sounds produced by bottlenose dolphins (Tursiops truncatus) were recorded in three locations along the Gulf of Mexico. Sounds were characterized as being tonal with low peak frequencies (mean?=?990 Hz), short duration (mean?=?0.069 s), highly harmonic, and being produced in trains. Sound duration, peak frequency and number of sounds in trains were not significantly different between Mississippi and the two West Florida sites, however, the time interval between sounds within trains in West Florida was significantly shorter than in Mississippi (t?=?-3.001, p?=?0.011). The sounds were significantly correlated with groups engaging in social activity (F=8.323, p=0.005). The peak frequencies of these sounds were below what is normally thought of as the range of good hearing in bottlenose dolphins, and are likely subject to masking by boat noise. 相似文献
53.
Let \(\Omega \) be a bounded smooth domain of \(R^{n}\). We study the asymptotic behaviour of the solutions to the equation \(\triangle u-|Du|^{q}=f(u)\) in \(\Omega , 1<q<2,\) which satisfy the boundary condition \(u(x)\rightarrow \infty \) as \(x\rightarrow \partial \Omega \). These solutions are called large or blowup solutions. Near the boundary we give lower and upper bounds for the ratio \(\psi (u)/\delta \), where \(\psi (u) = \int _{u}^{\infty }1/\sqrt{2F}dt\), \(F'=f\), \(\delta =dist(x,\partial \Omega )\) or for the ratio \(u/\delta ^{(2-q)/(1-q)}\). When in particular the ratio \(f/F^{q/2}\)is regular at infinity, we find again known results (Bandle and Giarrusso, in Adv Diff Equ 1, 133–150, 1996; Giarrusso, in Comptes Rendus de l’Acad Sci 331, 777–782 2000). 相似文献
54.
Let \({F_1, F_2, \ldots, F_k}\) be graphs with the same vertex set V. A subset \({S \subseteq V}\) is a simultaneous dominating set if for every i, 1 ≤ i ≤ k, every vertex of F i not in S is adjacent to a vertex in S in F i ; that is, the set S is simultaneously a dominating set in each graph F i . The cardinality of a smallest such set is the simultaneous domination number. We present general upper bounds on the simultaneous domination number. We investigate bounds in special cases, including the cases when the factors, F i , are r-regular or the disjoint union of copies of K r . Further we study the case when each factor is a cycle. 相似文献
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58.
Shlomo Shoval Ester Yadin Gerard Panczer 《Journal of Thermal Analysis and Calorimetry》2011,104(2):515-525
The work deals with the FT-IR and micro-Raman spectroscopy study of the pseudo-amorphous and crystalline thermal phases in
the composition of calcareous Iron Age pottery from the Galilee. The application of second-derivative and curve-fitting techniques
improves the identification of the thermal phases in the composition of the pottery and makes it possible to analyze the pseudo-amorphous
phases which are formed during the firing of the clayey raw material to pottery. This technique makes it possible to distinguish
between meta-smectite and meta-kaolinite and to estimate the firing temperature of the pottery. The Micro-Raman spectroscopy
is sensitive to the structural degree of ordering of the thermal phases and enables point analysis of peculiar components
in the composition of the pottery. Based on the spectroscopic study, it is concluded that the calcareous pottery contained
large amounts of microcrystalline-recarbonated calcite mixed with the meta-clay. The large amount of recarbonated calcite
in the pottery material and the relatively low firing temperature indicates that instead of sintering the clay, lime technology
was used for the cementation of the calcareous vessels. This process took place after the firing by recarbonation of the decomposed
calcite which leads to cementation of the vessels with microcrystalline calcite. 相似文献
59.
A three-dimensional elliptic singular perturbation problem with discontinuous boundary values is considered. The solution of the problem is written in terms of a double integral. A saddle point analysis is used to obtain a first approximation, which is expressed in terms of a function that can be viewed as a generalization of the complementary error function. 相似文献
60.
Yair Caro 《Discrete Mathematics》1996,160(1-3):229-233
We prove the following result: For every two natural numbers n and q, n q + 2, there is a natural number E(n, q) satisfying the following:
1. (1) Let S be any set of points in the plane, no three on a line. If |S| E(n, q), then there exists a convex n-gon whose points belong to S, for which the number of points of S in its interior is 0 (mod q).
2. (2) For fixed q, E(n,q) 2c(q)·n, c(q) is a constant depends on q only.
Part (1) was proved by Bialostocki et al. [2] and our proof is aimed to simplify the original proof. The proof of Part (2) is completely new and reduces the huge upper bound of [2] (a super-exponential bound) to an exponential upper bound. 相似文献