Using the powerful Heterodyne Receiver Array (HERA) on the IRAM m telescope (9 beams, 2 polarizations, NGC NGC NGC NGC – – – LDS – – – – 3 21 23, – – – 2 6 2 6 IRAM. from wastewater by maghemite nanoparticles. Water Research, , 39(18): – Iram M, Guo C, Guan Yet al. Adsorption and magnetic removal of.
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Gratier 1Irsm. Roueff 3M. Gerin 2J. Goicoechea 4S. Bardeau 1A. Sievers 5F. Le Petit 3J. Le Bourlot 3A. Belloche 6 and D. Janssen, Meudon Cedex, France e-mail: Carretera de Ajalvir, Km 4.
Pure gas-phase chemistry models do not succeed in reproducing the measured abundances of small hydrocarbons in the interstellar medium. Information on key gas-phase progenitors irak these molecules sheds light on this problem.
We aim to constrain the chemical content of the Horsehead mane with a millimeter unbiased line survey at two positions, namely the photo-dissociation region PDR and the nearby shielded core.
Laboratory spectroscopy is underway to confirm these results. Molecular ions play an important role in the physics and chemistry of the insterstellar medium. They trace the gas physical conditions, e. The spectra and the Gaussian fits are shown as black histograms and green curves, respectively. Simple hydrocarbon molecules, such as C 2 H, C 3 H, and C 3 H 2 have been detected in a wide variety of sources from diffuse e. Two positions are observed: To compute the spectroscopic parameters associated with the set of unidentified lines, we used higher order improvements to the simple model of a linear rotor.
We therefore assume that the eight lines have the same line width. This is likely for two reasons. This assumption enables a quick fit convergence when we start the fit with the following initial values: Displayed integrated intensities are expressed in the main beam temperature scale.
Contour levels are shown in the grey-scale lookup tables. This led us to conclude that the species is a reactive molecule with a spatial distribution similar to small hydrocarbon chains. The illuminating star is positioned at the right of the plots. The legend at the bottom of the figure presents the line coding for the curves: We used the Ohio State University osu pure gas-phase chemical network upgraded for photochemical studies.
The left column presents the profiles computed by the code, which samples the UV-illuminated gas on a finer spatial grid than the UV-shielded gas to correctly represent the steep physical and chemical gradients.
We only consider the most stable isomers to compare the measured and modeled abundances. This is due to a combination of two effects.
Indeed, the modeled and predicted abundances irram c-C 3 H 2 are consistent, while the modeled abundance of C 2 H is still one order of magnitude lower than the measured abundance cf. The measured abundances are typically one and two orders of magnitude higher than the modeled abundances for C 2 H and C 3 H 2.
The green lines are Gaussian fits. We wish to know to lram development order we can significantly fit the frequency model to the observed data. Lines simultaneously observed in the cut displayed in Fig.
Column densities and abundances with respect to the number of protons, i. Data correspond to usage on the plateform after The current usage metrics is available hours after online publication and is updated daily on week days. Previous article Next article. Metrics Show article metrics. Services Articles citing this article CrossRef Summary Acknowledgments References Appendix A: List of tables Ira, of figures.
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