منابع مشابه
A new method for Eosin preparation and examination of its absorption and emission spectra
Eosin is one of the original dyes of xanthenes derivatives. It is also one of the main derivatives of fluorescein and has brilliant fluorescence. Eosin disodium salt called "Eosin Y" is the most useful form of this compound. In common procedures, eosin is usually obtained by the action of bromine on fluorescein, which has not good yield and purity degree. In this research, it is prepared by the...
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For two graphs $mathrm{G}$ and $mathrm{H}$ with $n$ and $m$ vertices, the corona $mathrm{G}circmathrm{H}$ of $mathrm{G}$ and $mathrm{H}$ is the graph obtained by taking one copy of $mathrm{G}$ and $n$ copies of $mathrm{H}$ and then joining the $i^{th}$ vertex of $mathrm{G}$ to every vertex in the $i^{th}$ copy of $mathrm{H}$. The neighborhood corona $mathrm{G}starmathrm{H}$ of $mathrm{G}$ and $...
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We have collected pulsar flux density observations and compiled spectra of 281 objects. The database of Lorimer et al. (1995) has been extended to frequencies higher than 1.4 GHz and lower than 300 MHz. Our results show that above 100 MHz the spectra of the majority of pulsars can be described by a simple power law with average value of spectral index < α >= −1.8 ± 0.2. A rigorous analysis of s...
متن کاملOn the response spectra of cracked beams under different types of moving force
In this paper, the dynamic responses of cracked beams under different moving forces, including moving load, moving mass, moving oscillator, and four-degrees-of-freedom moving system, are investigated. Structural elements such as beams are designed to withstand the predicted loads, but unfortunately, they are always exposed to unpredictable damage such as cracks. Several factors may cause these ...
متن کاملSpectra of Some New Graph Operations and Some New Class of Integral Graphs
In this paper, we define duplication corona, duplication neighborhood corona and duplication edge corona of two graphs. We compute their adjacency spectrum, Laplacian spectrum and signless Laplacian. As an application, our results enable us to construct infinitely many pairs of cospectral graphs and also integral graphs.
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ژورنال
عنوان ژورنال: Nature
سال: 1930
ISSN: 0028-0836,1476-4687
DOI: 10.1038/125014a0