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31.
通过熔盐法制备TiB2载体,并采用简单的沉淀-沉积法制备了Co/TiB2磁性可回收纳米催化剂,用于室温催化氨硼烷(NH3BH3)溶液产氢及串联降解对硝基苯酚(4-NP)及偶氮染料酸性橙7(AO7)、酸性红1(AR1)和甲基橙(MO)等有机污染物。采用X射线衍射、扫描电子显微镜、透射电子显微镜、X射线光电子能谱、振动样品磁强计等表征方法对催化剂的微观形貌和结构等进行分析。结果表明,Co纳米粒子均匀地分布在TiB2载体表面,晶粒尺寸约为40 nm,并且被TiB2载体包覆,具有典型的金属-载体强相互作用。Co/TiB2表现出优异的室温催化NH3BH3溶液产氢活性,产氢速率为565.8 molH2·molcat-1·h-1。在串联降解有机污染物反应中,Co/TiB2在7 min内催化4-NP氨基化的转化率接近100%,反应速率常数高达0.72 min-1;降解AO7的反应速率常数在3种偶氮染料中最高(0.34 min-1)。通过EPR-DMPO(EPR=电子顺磁共振,DMPO=5,5-二甲基-1-吡咯啉-N-氧化物)自由基捕获实验检测出Co/TiB2+NH3BH3催化体系中产生大量的氢自由基(·H)。得益于·H的强还原性,Co/TiB2+NH3BH3催化体系能够将4-NP氨基化为具有更高价值的对氨基苯酚(4-AP),同时能够还原偶氮染料分子中的显色基团偶氮基(—N=N—)。 相似文献
32.
33.
一个二元叠加码(s,l)-码在许多领域有着极为广泛的应用.利用有限域F_q上的向量空间的子空间构作了矩阵M_q(m,d,k),并证明了它是一个(s,l)一码,计算了(s,l)-码的参数. 相似文献
34.
35.
This paper studies the periodic feedback stabilization for a class of linear T -periodic evolution equations. Several equivalent conditions on the linear periodic feedback stabilization are obtained. These conditions are related to the following subjects: the attainable subspace of the controlled evolution equation under consideration; the unstable subspace (of the evolution equation with the null control) provided by the Kato projection; the Poincaré map associated with the evolution equation with the null control; and two unique continuation properties for the dual equations on different time horizons [0,T] and [0,n0T] (where n0 is the sum of algebraic multiplicities of distinct unstable eigenvalues of the Poincaré map). It is also proved that a T-periodic controlled evolution equation is linear T-periodic feedback stabilizable if and only if it is linear T-periodic feedback stabilizable with respect to a finite-dimensional subspace. Some applications to heat equations with time-periodic potentials are presented. 相似文献
36.
L. P. Vlasov 《Mathematical Notes》1997,61(1):38-47
Functionals (vector measures) defined on the spaceC(Q, X) of continuous abstract functions (whereQ is a compact Hausdorff space andX is a Banach space) and attaining their norm on the unit sphere are considered. A characterization of such functionals is
given in terms of the Radon-Nikodym derivative of the vector measure with respect to the variation of the measure and in terms
of analogs of the derivative. Applications to the characterization of finite-codimensional subspaces with the best approximation
property are given. Similar results are obtained for the spaceB(Q, Σ, X) of uniform limits of simple functions.
Translated fromMatematicheskie Zametki, Vol. 61, No. 1, pp. 45–56, January, 1997.
Translated by V. E. Nazaikinskii 相似文献
37.
We study properties of Jordan representations ofH-dissipative operators in a finite-dimensional indefiniteH-space. An algebraic proof is given of the fact that such operators always have maximal semidefinite invariant subspaces.
Translated fromMatematicheskie Zametki, Vol. 63, No. 2, pp. 163–169, February, 1998.
The authors axe grateful to Professor A. A. Shkalikov for useful discussions.
The research of the first author was supported by INTAS under grant No. 93-0249. The research of the second author was supported
by the International Science Foundation and the Russian Government under grant No. NZP300. 相似文献
38.
39.
Multi-item inventory models with two storage facility and bulk release pattern are developed with linearly time dependent
demand in a finite time horizon under crisp, stochastic and fuzzy-stochastic environments. Here different inventory parameters—holding
costs, ordering costs, purchase costs, etc.—are assumed as probabilistic or fuzzy in nature. In particular cases stochastic
and crisp models are derived. Models are formulated as profit maximization principle and three different approaches are proposed
for solution. In the first approach, fuzzy extension principle is used to find membership function of the objective function
and then it’s Graded Mean Integration Value (GMIV) for different optimistic levels are taken as equivalent stochastic objectives.
Then the stochastic model is transformed to a constraint multi-objective programming problem using Stochastic Non-linear Programming
(SNLP) technique. The multi-objective problems are transferred to single objective problems using Interactive Fuzzy Satisfising
(IFS) technique. Finally, a Region Reducing Genetic Algorithm (RRGA) based on entropy has been developed and implemented to
solve the single objective problems. In the second approach, the above GMIV (which is stochastic in nature) is optimized with
some degree of probability and using SNLP technique model is transferred to an equivalent single objective crisp problem and
solved using RRGA. In the third approach, objective function is optimized with some degree of possibility/necessity and following
this approach model is transformed to an equivalent constrained stochastic programming problem. Then it is transformed to
an equivalent single objective crisp problem using SNLP technique and solved via RRGA. The models are illustrated with some
numerical examples and some sensitivity analyses have been presented. 相似文献
40.
Guangjun Zhao 《Discrete Mathematics》2007,307(22):2861-2865
A new q-analogue of the sum of cubes is given with a combinatorial interpretation on the lattice of subspaces. 相似文献