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951.
In this paper, we study the spectrum of the Dirichlet Laplacian in a bounded (or, more generally, of finite volume) open set R
n
(n1) with fractal boundary of interior Minkowski dimension (n–1,n]. By means of the technique of tessellation of domains, we give the exact second term of the asymptotic expansion of the counting functionN() (i.e. the number of positive eigenvalues less than ) as +, which is of the form /2 times a negative, bounded and left-continuous function of . This explains the reason why the modified Weyl-Berry conjecture does not hold generally forn2. In addition, we also obtain explicit upper and lower bounds on the second term ofN(). 相似文献
952.
用原子吸收光谱法测下了“东北水三七”根、茎、叶的21种化学元素,结果表明,不同部位的元素含量有一定差别。 相似文献
953.
The effects of media properties including buffers, acidity, solvents and surfactant on horseradish peroxidase-catalyzed fluorogenic reaction were investigated. The results showed that the so-called non-fluorescent hydrogen donors were in fact fluorescent. There existed an acid—base equilibrium in the fluorescent dimer product. For p -hydroxyphenylpropionic acid, a pKa value of 8.0 for the product was obtained from its titration curve. The product fluorescence increased with higher pH, however, a longer time was needed to reach the reaction equilibrium due to the pH mismatch problem. Cationic micelles cetyltrimethylammonium bromide and cetyltrimethylammonium chloride could reduce the pH mismatch and offered a way to further increase the determination sensitivity. Finally, a micelle-enhanced flow-injection analysis of horseradish peroxidase is suggested. 相似文献
954.
For the Kantorovich polynomial approximationK n (f, t), 1<p≤∞, we prove that, for somem, This equivalence includes a strong converse inequality of type B. 相似文献
955.
Chen Dirong 《分析论及其应用》1994,10(4):110-117
Let G be a Polya frequency density and
its periodization. We get the exact value of upper approximation of S1
(G), which is a convolution class with kernel G, by cardinal splines corresponding to G. Similar result has been obtained for
periodic convolution class with kernel
as well.
Supported in part by Postdoctral Fellowship Foundation provided by Chinese Academy of Sciences 相似文献
956.
A difference setD in a groupG is called a skew Hadamard difference set (or an antisymmetric difference set) if and only ifG is the disjoint union ofD, D(–1), and {1}, whereD(–1)={d–1|dD}. In this note, we obtain an exponent bound for non-elementary abelian groupG which admits a skew Hadamard difference set. This improves the bound obtained previously by Johnsen, Camion and Mann. 相似文献
957.
Chen KR 《Physical review letters》1994,72(22):3534-3537
958.
959.
960.