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101.
《Arabian Journal of Chemistry》2022,15(2):103603
Heterogeneous catalysts, named SPS (sodium potassium silicates), were synthesized with an alternative silica (MPI silica) obtained from beach sand. In this work, the MPI was modified with NaOH and KOH producing silicate-based catalyst for biodiesel synthesis from waste cooking oil (WCO). The obtained catalyst was characterized by XRD, CO2-TPD, the Hammett basicity test, XRF, FESEM, EDX, FTIR and TG/DTG. The results confirmed the presence of K2O/Na2O oxides and their silicates, the main active sites responsible for the catalytic action. CO2-TPD and the Hammett basicity data suggested the presence of weak, medium and strong basic sites. Biodiesel yield was about 92% and the SPS catalyst was reused for five cycles. The biodiesel conversion by NMR 1H was about 93.89%. The DTG deconvolution revealed the decomposition of four typical biodiesel compounds (R2 = 0.9987). The method applied for the WCO biodiesel production using SPS catalyst represents an environmentally friendly process, based on low-cost material and reuse of waste biomass. 相似文献
102.
The electromagnetic radiation of a quantum semiconductor nanorod (considered in a dipole model), placed into a multilayered microsphere with alternative spherical stack, is studied. We found that the frequency spectrum consists of series of narrow and well separated peaks even in a lossy case. In the band of such peaks the great part of the field energy is located in the structure of the stack and practically does not leave the microsphere. A possibility of resonant coupling of photon states in the area of nanorods is discussed. 相似文献
103.
Thomas Hagen 《Journal of Mathematical Analysis and Applications》2003,288(2):634-645
In this paper we study existence, uniqueness and regularity of solutions for the equations governing the forced elongation of fluids with differential constitutive law of Jeffreys type. These equations consist of nonlinear first-order hyperbolic equations in one spatial dimension. Forced elongation is imposed through velocity boundary conditions at the domain entry and exit. The existence result is based on the Schauder fixed point theorem and energy methods in the space of boundary-regular functions. 相似文献
104.
Kizmaz [13] studied the difference sequence spaces e∞(△), c(△), and c0(△).Several article dealt with the sets of sequences of m-th order difference of which are bounded, convergent, or convergent to zero. Altay and Basar [5] and Altay, Basar, and Mursaleen [7] introduced the Euler sequence spaces eτ0, eτ0, andeτ∞, respectively. The main purpose of this article is to introduce the spaces eτ0(△(m)), eτc(△(m)), and eτ∞(△(m)) consisting of all sequences whose mth order differences are in the Euler spaces eτ0, eτc, and eτ∞, respectively. Moreover, the authors give some topological properties and inclusion relations, and determine the α-, β-, and γ-duals of the spaces eτ0(△(m)), eτc(△(m)), and eτ∞(△(m)), and the Schauder basis of the spaces eτ0(△(m)), eτc(△(m)). The last section of the article is devoted to the characterization of some matrix mappings on the sequence space eτc(△(m)). 相似文献
105.
The scaling limit and Schauder bounds are derived for a singular integral operator arising from a difference equation approach
to monodromy problems.
Research supported in part by National Science Foundation grants DMS-02-45371 and DMS-04-05519. 相似文献
106.
Banach空间的某类分解 总被引:1,自引:1,他引:0
石峰 《数学物理学报(A辑)》1998,18(3):318-323
该文从Schauder分解出发,考虑了由一类具有特殊基的Banach空间Y所生成的Banach空间Y(Xi,i∈N)(特别是当每个Xi均为Y的标量域)的一些性质,以及它们之间的联系. 相似文献
107.
Taka-Aki Shiraishi 《Annals of the Institute of Statistical Mathematics》1985,37(1):519-527
Summary Local powers of two- andk-sample rank tests under alternatives of contaminated distributions are investigated. It is shown that the rank tests based
on normal scores and Wilcoxon scores are superior to thet-test or theF-test for many choices of alternatives of contaminated distributions and that the values of the asymptotic relative efficiency
of the rank test based on Wilcoxon scores with respect to the normal scores are about one in all the investigated cases. 相似文献
108.
A. Taskaraev 《Mathematical Notes》1998,64(5):658-662
The existence and uniqueness of a surface with given geometric characteristics is one of the important topical problems of
global differential geometry. By stating this problem in terms of analysis, we arrive at second-order elliptic and parabolic
partial differential equations. In the present paper we consider generalized solutions of the Monge-Ampère equation ||z
ij
|| = ϕ(x, z, p) in Λ
n
, wherez = z(x
1,...,z
n
) is a convex function,p = (p
1,...,P
n) = (∂z/∂x
1,...,ϖz/ϖx
n), andz
ij =ϖ
2
z/ϖx
i
ϖx
j. We consider the Cayley-Klein model of the space Λ
n
and use a method based on fixed point principle for Banach spaces.
Translated fromMatematicheskie Zametki, Vol. 64, No. 5, pp. 763–768, November, 1998. 相似文献
109.
本文利用Schauder不动点定理的方法和上、下解技巧,研究了时滞格微分方程组的行波解,给出了当系统的非线性项满足“拟单调条件”和“指数拟单调条件”时行波解的存在性. 相似文献
110.
Existence of traveling wave fronts for delayed lattice differential equations is established by Schauder fixed point theorem. The main result is applied to a delayed and discretely diffusive model for the population of Daphnia magna. 相似文献