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Though H2CO, H2CS, H2CCC, H2CCCC, H2CCO have been identified in cool interstellar molecular clouds, identification of H2CC is still awaited. To analyze its spectrum, collisional rate coefficients are required. We have calculated collisional rate coefficients for rotational transitions between 23 levels of ortho and para H2CC for kinetic temperatures 10, 20, 30, 40, and 50 K. The scattering problem is analyzed using the computer code MOLSCAT where the colliding partner is He atom. The interaction between H2CC and He has been calculated with GAUSSIAN 2003. For the interaction potential obtained with GAUSSIAN 2003, MOLSCAT is used to derive the parameters q(L,M,M|E)q(L,M,M|E) as a function of energy E   of the colliding partner. After averaging the parameters q(L,M,M|E)q(L,M,M|E) over a Maxwellian distribution, the parameters Q(L,M,M|T)Q(L,M,M|T) as a function of the kinetic temperature T in the cloud are obtained. Finally, the collisional rate coefficients have been calculated.  相似文献   

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We present medium resolution near-infrared host galaxy spectra of low redshift quasars, PG 0844+3490844+349 (z = 0.064), PG 1226+0231226+023 (z = 0.158), and PG 1426+0151426+015 (z = 0.086). The observations were done by using the Infrared Camera and Spectrograph (IRCS) at the Subaru 8.2 m telescope. The full width at half maximum of the point spread function was about 0.3 arcsec by operations of an adaptive optics system, which can effectively resolve the quasar spectra from the host galaxy spectra. We spent up to several hours per target and developed data reduction methods to reduce the systematic noises of the telluric emissions and absorptions. From the obtained spectra, we identified absorption features of Mg I (1.503 μm), Si I (1.589 μm) and CO (6-3) (1.619 μm), and measured the velocity dispersions of PG 0844+3490844+349 to be 132 ± 110 km s−1 and PG 1426+0151426+015 to be 264 ± 215 km s−1. By using an MBH–σMBHσ relation of elliptical galaxies, we derived the black hole (BH) mass of PG 0844+3490844+349, log(MBH/M)=7.7±5.5log(MBH/M)=7.7±5.5 and PG 1426+015,log(MBH/M)=9.0±7.51426+015,log(MBH/M)=9.0±7.5. These values are consistent with the BH mass values from broad emission lines with an assumption of a virial factor of 5.5.  相似文献   

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Crossings of the magnetopause near the subsolar point are analyzed using data of THEMIS mission. Variations of the magnetic field near magnetopause measured by one of THEMIS satellites are studied and compared with simultaneous measurements in the solar wind by another THEMIS satellite. The time delay of the solar wind arrival at the subsolar point of the magnetopause is taken into account. 30 and 90 s averaging of the magnetic field in the magnetosheath is produced. The results of averaging are compared with the results of measurements in the solar wind before the bow shock and foreshock. It is shown, that BxBx component of the magnetic field near magnetopause is near to zero, which supports the possibility to consider the magnetopause as the tangential discontinuity. Comparatively good correlation of ByBy component in the solar wind and near the magnetopause is observed. The correlation of BzBz component near the magnetopause and IMF is practically absent, the sign of the BzBz near the subsolar point does not coincide with the sign of IMF BzBz in ∼30% cases.  相似文献   

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We propose a test of the gravitational time dilation in general relativity by long term clock comparison between two stations separated in height. The geopotential difference between the two National time keeping centers in China, Lintong (A)(A) and Beijing (B)(B) is around 4000 geopotential unit, which corresponds to the height difference of 400 m. Two clocks CACA and CBCB are fixed at stations A and B, respectively, which are synchronized at beginning by a portable clock C in a short time period with go-back synchronization approach. After one month, the clock C is again transported between A and B  , comparing the records of the keeping time by clocks CACA and CBCB, respectively. Calculations show that, after one month, the difference of the time durations between the clocks CACA and CBCB is around 121 ns, if general relativity is correct.  相似文献   

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Merging time series of ocean color-derived products provided by independent satellite missions supports related biogeochemical and environmental applications by combining temporally overlapping data sets and by increasing data coverage. The creation of a merged series of normalized water leaving radiances LWNLWN, the primary ocean color product, is presented for the Mediterranean Sea using the SeaWiFS and MODIS data records. The merging relies on an optically-based technique that combines the available LWNLWN signal in a spectrally consistent way. Validation statistics indicate uncertainties associated with the merged LWNLWN decreasing from 23% at 412 nm to 12% in the 500- to 555-nm spectral range. The inter-comparison of the sensor-specific products, conducted at the scale of the basin for daily-to-monthly time scales, indicates an overall consistency. The level of differences varies with the wavelength considered and shows a marked seasonal cycle, with differences that tend to be higher in winter. The merged series is remarkably consistent with the sensor-specific data, with average absolute percent differences lower than 10% for all wavelengths below 555 nm. The benefit of merging in terms of sampling frequency over the basin is also illustrated. A merged series of LWNLWN data based on the two considered missions provides valid data over 36% of the basin area on a daily basis.  相似文献   

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Using the bulge data from AGN image decomposition with ground-based observations, we calculate the ratios of the central supermassive black hole mass(SMBH) to the Bulge mass (Mbh/MbulgeMbh/Mbulge) in a sample of X-ray selected AGNs, including 15 Narrow-line Seyfert 1 galaxies (NLS1s) and 18 broad-line Seyfert 1 galaxies (BLS1s). We found that the mean value of log(Mbh/Mbulge)log(Mbh/Mbulge) is -3.81±0.11-3.81±0.11 for 15 NLS1s, and -2.91±0.13-2.91±0.13 for 18 BLS1s, showing the lower Mbh/MbulgeMbh/Mbulge in NLS1s relative to BLS1s. The calculation shows that the Bulge mass from the host image decomposition in NLS1s is statistically smaller than that from Hubble-type correction method, and a linear mass relation is suggested for NLS1s and a nonlinear mass relation for BLS1s. The studying of host galaxies with ground-based observations strongly limited by the atmospheric seeing. We need to do the decomposition of host images for NLS1s with Hubble Space Telescope observation in the future.  相似文献   

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The objectives of this research were to determine photosynthesis, evapotranspiration and growth of lettuce at long-term low atmospheric pressure. Lettuce (Lactuca sativa L. cv. Youmaicai) plants were grown at 40 kPa total pressure (8.4 kPa pO2pO2) or 101 kPa total pressure (20.9 kPa pO2pO2) from seed to harvest for 35 days. Germination rate of lettuce seeds decreased by 7.6% at low pressure, although this was not significant. There was no significant difference in crop photosynthetic rate between hypobaria and ambient pressure during the 35-day study. The crop evapotranspiration rate was significantly lower at low pressure than that at ambient pressure from 20 to 30 days after planting (DAP), but it had no significant difference before 20 DAP or after 30 DAP. The growth cycle of lettuce plants at low pressure was delayed. At low pressure, lettuce leaves were curly at the seedling stage and this disappeared gradually as the plants grew. Ambient lettuce plants were yellow and had an epinastic growth at harvest. The shoot height, leaf number, leaf length and shoot/root ratio were lower at low pressure than those at ambient pressure, while leaf area and root growth increased. Total biomass of lettuce plants grown at two pressures had no significant difference. Ethylene production at low pressure decreased significantly by 38.8% compared with ambient pressure. There was no significant difference in microelements, nutritional phytochemicals and nitrate concentrations at the two treatments. This research shows that lettuce can be grown at long-term low pressure (40 kPa) without significant adverse effects on seed germination, gas exchange and plant growth. Furthermore, ethylene release was reduced in hypobaria.  相似文献   

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We describe the current status and recent results from our Swift/VLT legacy survey, a VLT Large Programme aimed at characterizing the host galaxies of a homogeneously selected sub-sample of Swift   GRBs. The immediate goals are to determine the host luminosity function, study the effects of reddening, determine the fraction of LyαLyα emitters in the hosts, and obtain redshifts for targets without a reported one. The main effort so far has been the definition of a very carefully selected sample, obeying strict and well-defined criteria: 68 targets in total. Among the preliminary results is a large optical detection rate, the lack of extremely red objects (only one possible case in the sample) and an update of the Swift   GRB redshift distribution with 〈z〉∼2.0z2.0.  相似文献   

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