140 research outputs found
Расчет параметров эффективного дипольного момента молекул типа XY[2] на основе теории изотопозамещения
На основе теории изотопозамещения были получены соотношения, позволяющие рассчитать параметры эффективного дипольного момента изотопологов молекул типа XY[2] при симметричном замещении атомов. Исходной информацией, необходимой для осуществления подобных расчетов, является информация о структурных параметрах и параметрах эффективного дипольного момента “материнской” молекулы. Полученные результаты справедливы для комбинационных полос и обертонов. Полученные соотношения значительно упрощают, а в некоторых случаях, делают возможным процесс определения абсолютных интенсивностей линий поглощения изотопологов типа XY[2]
NGC 2571: An intermediate-age open cluster with a White Dwarf candidate
CCD UBVI imaging photometry was carried out in the field of the open cluster NGC 2571. From the analysis of our data we state the cluster is at a distance of 1380 ± 130 pc and its age is 504±10 ×106 yr. The cluster mass function has a slope larger than a typical Salpeter's law. There are two notorious features in NGC 2571: the cluster contains a high proportion of stars located below the reference line that are serious candidates to be metallic line stars (probably Am-Fm), and shows also a sharp gap along its main sequence that cannot be explained by a random process nor by a biased rejection of cluster members. A striking blue object was detected in the cluster field that could be a white dwarf candidate.Facultad de Ciencias Astronómicas y Geofísica
NGC 2571: An intermediate-age open cluster with a White Dwarf candidate
CCD UBVI imaging photometry was carried out in the field of the open cluster NGC 2571. From the analysis of our data we state the cluster is at a distance of 1380 ± 130 pc and its age is 504±10 ×106 yr. The cluster mass function has a slope larger than a typical Salpeter's law. There are two notorious features in NGC 2571: the cluster contains a high proportion of stars located below the reference line that are serious candidates to be metallic line stars (probably Am-Fm), and shows also a sharp gap along its main sequence that cannot be explained by a random process nor by a biased rejection of cluster members. A striking blue object was detected in the cluster field that could be a white dwarf candidate.Facultad de Ciencias Astronómicas y Geofísica
Percutaneous septal ablation for left mid-ventricular obstructive hypertrophic cardiomyopathy: a case report
BACKGROUND: Mid-ventricular obstructive hypertrophic cardiomyopathy (MVOHC) is a rare type of cardiomyopathy. The diagnosis is based on the hourglass appearance on the left ventriculogram and the presence of pressure gradient between apical and basal chamber of the ventriculum on the hemodynamic assessment. CASE PRESENTATION: The present case represents successful percutaneous treatment with septal ablation to patient with MVOHC associated with systolic anterior motion of the mitral valve and obstruction at both the mid-ventricular and outflow levels. CONCLUSION: Alcohol septal ablation has been proposed as less invasive alternatives to surgery in patients with MVOHC
An X-ray Survey of Wolf-Rayet Stars in the Magellanic Clouds. II. The ROSAT PSPC and HRI Datasets
Wolf-Rayet (WR) stars in the Magellanic Clouds (MCs) are ideal for studying
the production of X-ray emission by their strong fast stellar winds. We have
started a systematic survey for X-ray emission from WR stars in the MCs using
archival Chandra, ROSAT, and XMM-Newton observations. In Paper I, we reported
the detection of X-ray emission from 29 WR stars using Chandra ACIS
observations of 70 WR stars in the MCs. In this paper, we report the search and
analysis of archival ROSAT PSPC and HRI observations of WR stars. While useful
ROSAT observations are available for 117 WR stars in the MCs, X-ray emission is
detected from only 7 of them. The detection rate of X-ray emission from MCs WR
stars in the ROSAT survey is much smaller than in the Chandra ACIS survey,
illustrating the necessity of high angular resolution and sensitivity. LMC-WR
101-102 and 116 were detected by both ROSAT and Chandra, but no large long-term
variations are evident.Comment: To appear in The Astrophysical Journal Supplement. A version with
full resolution figures can be obtained upon request to [email protected]
NGC 2571: An intermediate-age open cluster with a White Dwarf candidate
CCD UBVI imaging photometry was carried out in the field of the open cluster NGC 2571. From the analysis of our data we state the cluster is at a distance of 1380 ± 130 pc and its age is 504±10 ×106 yr. The cluster mass function has a slope larger than a typical Salpeter's law. There are two notorious features in NGC 2571: the cluster contains a high proportion of stars located below the reference line that are serious candidates to be metallic line stars (probably Am-Fm), and shows also a sharp gap along its main sequence that cannot be explained by a random process nor by a biased rejection of cluster members. A striking blue object was detected in the cluster field that could be a white dwarf candidate.Facultad de Ciencias Astronómicas y Geofísica
Optical polarization observations of NGC 6231: evidence for a past SN fingerprint
We present the first linear multicolor polarization observations for a sample
of 35 stars in the direction of the Galactic cluster NGC 6231. We have found a
complex pattern in the angles of the polarimetric vectors. Near the core of
this cluster the structure shows a semi-circular pattern that we have
interpreted as a re-orientation of the dust particles, showing the morphology
of the magnetic field. We propose that a supernova event has occurred some time
ago and produced a shock on the local ISM. We discuss in this paper independent
confirmations othis event, both from the studies on the diffuse interstellar
absorptions Crawford (2001) and the results of the pre-main sequence stars
(PMS) given by Sung et al. (1998). We also show that a supernova is supported
by the evolutive status of the cluster.Comment: 24 pages, 4 figures, ApJ Accepte
Проект установки получения 9-этоксикарбазола
Цель работы – спроектировать установку поучения 9-этоксикарбазола с мощностью 66 тонн в год. Объектом разработки является алкилирование карбазола этиленхлоргидрином в присутствии ацетона и гидроксида натрия. Целью проектирования является разработка комплекса взаимосвязанных процессов, обеспечивающих выработку требуемого продукта нужного качества.The work purpose – to design lecture installation 9 ethoxydibenzo-pyrroles with a power of 66 tons per year. Object of development is the dibenzo-pyrrole alkylation etilenkhlorgidriny in the presence of acetone and sodium hydroxide. The purpose of projection is development of a complex of the interdependent processes providing development of the required product of the necessary quality
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