1,960 research outputs found
Molecular Lines of 13 Galactic Infrared Bubble Regions
We investigated the physical properties of molecular clouds and star
formation processes around infrared bubbles which are essentially expanding HII
regions. We performed observations of 13 galactic infrared bubble fields
containing 18 bubbles. Five molecular lines, 12CO (J=1-0), 13CO (J=1-0),
C18O(J=1-0), HCN (J=1-0), and HCO+ (J=1-0), were observed, and several publicly
available surveys, GLIMPSE, MIPSGAL, ATLASGAL, BGPS, VGPS, MAGPIS, and NVSS,
were used for comparison. We find that these bubbles are generally connected
with molecular clouds, most of which are giant. Several bubble regions display
velocity gradients and broad shifted profiles, which could be due to the
expansion of bubbles. The masses of molecular clouds within bubbles range from
100 to 19,000 solar mass, and their dynamic ages are about 0.3-3.7 Myr, which
takes into account the internal turbulence pressure of surrounding molecular
clouds. Clumps are found in the vicinity of all 18 bubbles, and molecular
clouds near four of these bubbles with larger angular sizes show shell-like
morphologies, indicating that either collect-and-collapse or radiation-driven
implosion processes may have occurred. Due to the contamination of adjacent
molecular clouds, only six bubble regions are appropriate to search for
outflows, and we find that four of them have outflow activities. Three bubbles
display ultra-compact HII regions at their borders, and one of them is probably
responsible for its outflow. In total, only six bubbles show star formation
activities in the vicinity, and we suggest that star formation processes might
have been triggered.Comment: 55 Pages, 32 figures. Accepted for publication in A
Path Loss Model with Antenna Height Dependency under Indoor Stair Environment
A novel, receiving antenna-height-dependent path loss model under indoor stair environment is presented. The effect of a cross-beam in the stairs is also considered. The proposed model can be applied to describe both of the line-of-sight (LOS) and the non-LOS (NLOS) cases. By using least square criterion, the parameters of proposed model are extracted. Finally, using the maximum likelihood estimation, the precision of the proposed model is evaluated by the standard deviation of shadowing
4-Desoxy-4β-(4-methoxycarbonyl-1,2,3-triazol-1-yl)podophyllotoxin dichloromethane solvate
In the title compound {systematic name: methyl 1-[12-oxo-10-(3,4,5-trimethoxyphenyl)-4,6,13-trioxatetracyclo[7.7.0.03,7.011,15]hexadeca-1,3(7),8-trien-16-yl]-1H-1,2,3-triazole-4-carboxylate dichloromethane solvate}, C26H25N3O9·CH2Cl2, the tetrahydrofuran ring and the six-membered ring fused to it both display envelope conformations
Isolation an Antimicrobial Action of Endophytic Fungi from Sophora Flavescens and Effects on Microorganism Circumstances in Soil
AbstractThe aim of this study was to isolate the endophytic fungi from Sophora flavescens and define its antimicrobial action and structure. The effects of this active substance on soil microorganism circumstances were also conducted. Column chromatography and freeze drying were used to isolate and purify the antimicrobial substance. TLC biological autoradiography was applied to trace. HPLC method was employed to measure the purity. Analysis of the structure used 1H-NMR, 13C-NMR and LC-MS methods. Plate method was applied to measure the effect on microorganism circumstances. The results showed that after isolating and purifying the fermentation liquor of BS001, the structure of bacteriostatic active composition was 6,7-(2′E)dibutenyl-5,8-dihydroxy-(Z)-cyclooct-2-ene-1,4-dione, which was identified by spectroscopy. The substance could increase the number of bacteria and fungi while decreased the number of antinomies in soil. A new antimicrobial substance 6,7-(2′E)dibutenyl-5,8 -dihydroxy- (Z)- cyclooct - 2- ene-1,4-dione was extracted from fermenting liquor of BS001 which was an endophytic fungi of Sophora flavescens. It could promote the beneficial flora but detrimental flora. This conclusion provides exploiture foreground for biopharmaceuticals and biopesticide
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