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991.
Efficiently enhanced energy storage performance of Ba2Bi4Ti5O18 film by co-doping Fe3+ and Ta5+ ion with larger radius 下载免费PDF全文
We present an efficient strategy, that is the co-substitution of Fe3+ and Ta5+ ions with large radius for Ti4+ ion, to enhance energy storage performance of Ba2Bi4Ti5O18 film. For the films co-doped with Fe3+ and Ta5+ ions, the maximum polarization under the same external electric field is improved because the radius of Fe3+ and Ta5+ ions is larger than that of Ti4+ ion. Moreover, due to the composition and chemical disorder, the relaxor properties are also slightly improved, which can not be achieved by the film doped with Fe3+ ions only. What is more, for the films doped with Fe3+ ion only, the leakage current density increases greatly due to the charge imbalance, resulting in a significant decrease in breakdown strength. It is worth mentioning that the breakdown strength of Fe3+ and Ta5+ ions co-doped film does not decrease due to the charge balance. Another important point is the recoverable energy storage density of the films co-doped with Fe3+ and Ta5+ ions has been greatly improved based on the fact that the maximum external electric field does not decrease and the maximum polarization under the same external electric field increases. On top of that, the hysteresis of the polarization has also been improved. Finally, the co-doped films with Fe3+ and Ta5+ ions have good frequency and temperature stability. 相似文献
992.
Wieczorek-Ciurowa K. Fela K. Kozak A. J. 《Journal of Thermal Analysis and Calorimetry》2001,65(2):655-660
Attempts have been made to replace aluminium(III) by chromium(III) in the ettringite structure because of practical importance
of a waste treatment technology. The optimum conditions of Ca6[Cr(OH)6]2(SO4)3⋅26H2O formation and its thermal stability are reported.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献
993.
We consider arithmetic varieties endowed with an action of the group scheme of n-th roots of unity and we define equivariant arithmetic K
0-theory for these varieties. We use the equivariant analytic torsion to define direct image maps in this context and we prove
a Riemann-Roch theorem for the natural transformation of equivariant arithmetic K
0-theory induced by the restriction to the fixed point scheme; this theorem can be viewed as an analog, in the context of Arakelov
geometry, of the regular case of the theorem proved by P. Baum, W. Fulton and G. Quart in [BaFQ]. We show that it implies
an equivariant refinement of the arithmetic Riemann-Roch theorem, in a form conjectured by J.-M. Bismut (cf. [B2, Par. (l),
p. 353] and also Ch. Soulé’s question in [SABK, 1.5, p. 162]).
Oblatum 22-I-1999 & 20-II-2001?Published online: 4 May 2001 相似文献
994.
Pietro De Poi 《manuscripta mathematica》2001,106(1):101-116
We discuss projective families of lines of ℙ
n
, and in particular congruences of order one. After giving general results, we obtain a complete classification of the case
of ℙ4 in which there is a fundamental curve.
Received: 2 August 2000 / Revised version: 11 July 2001 相似文献
995.
The aim of this paper is to obtain a classification of scrolls of genus 0 and 1, which are defined by a one-dimensional family
of lines meeting a certain set of linear spaces in p
n
. These ruled surfaces will be called incidence scrolls and such a set will be the base of the incidence scroll. Unless otherwise
stated, we assume that the base spaces are in general position.
Received: 1 December 2000 相似文献
996.
R. Silhol 《Mathematische Zeitschrift》2001,236(4):841-881
997.
S. J. Gardiner 《Constructive Approximation》2001,17(1):139-146
Let Ω be a domain in the extended complex plane such that ∞∈Ω . Further, let K= C / Ω and, for each n , let Q
n
be a monic polynomial of degree n with all its zeros in K . This paper is concerned with whether (Q
n
) can be chosen so that, if f is any holomorphic function on Ω and P
n
is the polynomial part of the Laurent expansion of Q
n
f at ∞ , then (P
n
/Q
n
) converges to f locally uniformly on Ω . It is shown that such a sequence (Q
n
) can be chosen if and only if either K has zero logarithmic capacity or Ω is regular.
January 21, 1999. Date accepted: August 17, 1999. 相似文献
998.
We improve over a sufficient condition given in [8] for uniqueness of a nondegenerate critical point in best rational approximation
of prescribed degree over the conjugate-symmetric Hardy space of the complement of the disk. The improved condition connects to error estimates in AAK approximation, and is necessary
and sufficient when the function to be approximated is of Markov type. For Markov functions whose defining measure satisfies
the Szego condition, we combine what precedes with sharp asymptotics in multipoint Padé approximation from [43], [40] in order
to prove uniqueness of a critical point when the degree of the approximant goes large. This lends perspective to the uniqueness
issue for more general classes of functions defined through Cauchy integrals. 相似文献
999.
The metal–substrate and metal–metal interactions (MSI, MMI) represent important effects determining the properties of supported catalysts, gas sensors and gettering alloys. We investigated the MSI and MMI effects by the X-ray photoelectron spectroscopy (XPS) and temperature programmed desorption (TPD) in the case of Pd films deposited on Al2O3 and Al substrates. The study shows that the particle-size dependent metal–substrate interaction plays an important role in CO–Pd chemisorption, namely, in the case of “aluminium rich” Pd–aluminium oxide interface. CO chemisorption exhibits a low-temperature desorption feature at 360 K characteristic for Pd–Al and very small Pd particles. The MSI is explained by the formation of a Pd–Al intermetallic interface exhibiting a strong bimetallic Pd–Al interaction. 相似文献
1000.
Ti—MCM—41的结构特征与芳烃羟化反应的化学亲和选择性 总被引:3,自引:0,他引:3
以不同硅源合成了Si/Ti比不同的Si-Ti-MCM-41,并在引入Ti的同时引入Al,合成了Si/Al比不同的Si-Ti-Al-MCM-41。XRD、TEM、低温N2吸附的表征结果说明,Ti-MCM-41具有长程有序一维孔道,且比表面积较高,FT-IR光谱表征说明,Ti对骨架Si的取代使MCM-41表面出现缺陷羟基。Al的引入有利于Ti-MCM-41有序结构的形成。且可调变Ti-MCM-41的表面性质。Ti-MCM-41在不同极性芳烃化合物的羟化过程中表现出化学亲和选择性,且调变Ti-MCM-41的表面性质可实现对化学亲和选择性的控制。 相似文献