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11.
A simple and rapid capillary electrophoretic method was developed for the simultaneous determination of noradrenaline (NA) and dopamine (DA) in Portulaca oleracea L. The buffer solution used in this method was 40 mM tris (hydroxymethyl) aminomethane (Tris)-H3PO4 at pH 2.00 containing 15% methanol. The effects of pH value, organic modifier, and applied voltage were investigated. The linear ranges of NA and DA were 0.5-100 microg/mL (r=0.9952) and 6.25-200 microg/mL (r=0.9992), respectively. The relative standard deviations of the corrected peak area were 6.73% and 4.26%, respectively. NA and DA in Portulaca oleracea L. were simultaneous determined successfully within 5.6 min. In this way, the contents of NA and DA in different parts (stem, leaves, and seeds) of P. oleracea L. and in different extracts of leaves with different solvents (distilled water, 50% methanol, and methanol) were studied. 相似文献
12.
S. B. Denisova E. G. Galkin V. T. Danilov Yu. I. Murinov 《Chemistry of Natural Compounds》2003,39(3):237-239
Simple sugars were isolated from the ethanol extract of Glycyrrhiza glabra L. root. The component composition of the carbohydrate fraction was established using GC-MS (gas-chromatographic separation and mass-spectrometric analysis). 相似文献
13.
Charles A. Micchelli 《Aequationes Mathematicae》1980,21(1):105-109
We show that, for the Chebyshev weight function (1–x
2)–1/2, the Cotes numbers for the quadrature rule with nodes at the zeros of the ultraspherical polynomialP
n
/()
are nonnegative if and only if –1/2<1. 相似文献
14.
15.
Chi-Keung Cheung 《Journal of Geometric Analysis》1992,2(2):105-119
In this paper we considered curvature conditions on a Kähler-Einstein surface of general type. In particular we showed that it has negative holomorphic sectional curvature if theL 2-norm of (3C 2 ?C 1 2 )/C 1 2 is sufficiently small, whereC 1 andC 2 are the first and second Chern classes of the surfaces. This generalizes a result of Yau on the uniformization of Kähler-Einstein surfaces of general type and with 3C 2 ?C 1 2 = 0. Also in the process, we obtain a necessary condition in terms of an inequality between Chern numbers for a Kähler-Einstein metric to have negative holomorphic sectional curvature. 相似文献
16.
A. A. Makarov 《Applied physics. B, Lasers and optics》1982,29(4):287-290
For the detection of the rare radioactive isotope41Ca, the possibilities of the earlier-proposed initial-state enrichment by continuous-wave laser radiation are examined. It is shown that the enrichment 1014 of 3d-states of the ion Ca II can be reached. As the method of enriched-state detection, the process of resonant charge exchange is analysed. For a further increase of the selectivity, the repetition of the cycle initial state enrichment plus resonant charge exchange is discussed. 相似文献
17.
Paul R. Beesack 《Aequationes Mathematicae》1976,14(3):293-301
Letx
1, ,x
n
be real numbers with
1
n
x
j
=0, |x
1
||x
2
||x
n
|, and
1
n
f(|x
i
|)=A>0, wheref is a continuous, strictly increasing function on [0, ) withf(0)=0. Using a generalized Chebycheff inequality (or directly) it is easy to see that an upper bound for |x
m
| isf
–1
(A/(n–m+1)). If (n–m+1) is even, this bound is best possible, but not otherwise. Best upper bounds are obtained in case (n–m+1) is odd provided either (i)f is strictly convex on [0, ), or (ii)f is strictly concave on [0, ). Explicit best bounds are given as examples of (i) and (ii), namely the casesf(x)=x
p
forp>1 and 0<p<1 respectively. 相似文献
18.
The differential cross-sections for the emission of M shell fluorescent X-rays from Th by 5·95 keV photons at eight angles
ranging from 50° to 120° have been measured. The differential cross-section is found to decrease with increase in the emission
angle showing anisotropic spatial distribution of M shell fluorescent X-rays. The present results contradict the predictions
of the calculations of Cooper and Zare [1] that the atomic inner shell vacancy states produced in photoionization are not
aligned but confirm those of Fluggeet al [2] and Scofield [3] that the vacancy states withJ > 1/2 are aligned. The integral M shell fluorescent emission cross sections have been determined from the measured angular
distribution coefficients and compared with theoretical integral cross-sections calculated by using theoretical values of
M subshell photoionization cross-sections, fluorescence yields and coster kronig transition probabilities available in literature.
The experimental and theoretical values of integral crosssections show a reasonable agreement. 相似文献
19.
By the application of the coinduction method as well as the Magri method to the ideal of real Hilbert–Schmidt operators we construct the hierarchies of integrable Hamiltonian systems on Banach Lie–Poisson spaces which consist of such types of operators. We also discuss their algebraic and analytic properties and solve them in dimensions, N=2,3,4. 相似文献
20.
The quantum group IGL
q
(N), the inhomogenization of GL
q
(N), is formulated with
-matrices. Theq-deformed universal enveloping algebra is constructed as the algebra of regular functionals in this formulation and contains the partial derivatives of the covariant differential calculus on the quantum space. 相似文献