3,451 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
Case report of a retroperitoneal cyst
This paper highlights retroperitoneal cysts, its clinical diagnosis, and treatment from a retrospective analysis of clinical data of a 49-year-old female patient diagnosed with retroperitoneal cyst treated in our department. The patient was admitted after an abdominal mass that was discovered on the lower left quadrant for more than six months, showed clinical manifestations. B-mode ultrasound and computed tomography (CT) examinations diagnosed it as a retroperitoneal cyst. A laparotomy was performed for a complete excision of the cyst. Intestinal cysts are rarely reported but retroperitoneal cysts are even more so. Its clinical symptoms are atypical, and therefore easily misdiagnosed before surgery. The best treatment is surgical excision of the cyst, whereby postoperative pathological examination can confirm the diagnosis
Modification of Transition-Metal Redox by Interstitial Water in Hexacyanometalate Electrodes for Sodium-Ion Batteries.
A sodium-ion battery (SIB) solution is attractive for grid-scale electrical energy storage. Low-cost hexacyanometalate is a promising electrode material for SIBs because of its easy synthesis and open framework. Most hexacyanometalate-based SIBs work with aqueous electrolyte, and interstitial water in the material has been found to strongly affect the electrochemical profile, but the mechanism remains elusive. Here we provide a comparative study of the transition-metal redox in hexacyanometalate electrodes with and without interstitial water based on soft X-ray absorption spectroscopy and theoretical calculations. We found distinct transition-metal redox sequences in hydrated and anhydrated NaxMnFe(CN)6·zH2O. The Fe and Mn redox in hydrated electrodes are separated and are at different potentials, leading to two voltage plateaus. On the contrary, mixed Fe and Mn redox in the same potential range is found in the anhydrated system. This work reveals for the first time how transition-metal redox in batteries is strongly affected by interstitial molecules that are seemingly spectators. The results suggest a fundamental mechanism based on three competing factors that determine the transition-metal redox potentials. Because most hexacyanometalate electrodes contain water, this work directly reveals the mechanism of how interstitial molecules could define the electrochemical profile, especially for electrodes based on transition-metal redox with well-defined spin states
Robust high-temperature magnetic pinning induced by proximity in YBa2Cu3O7-8/La0.67Sr0.33MnO3 hybrids
An elaborately designed bilayer consisting of superconducting YBa2Cu3O7-6 (YBCO) and ferromagnetic La0.67Sr0.33MnO3-6 (LSMO) was prepared on a single crystal LaAlO3 substrate by pulsed laser deposition (PLD), with a view to understanding the mechanism behind the influence of superconductor/ferromagnet proximity on the critical current density, Jc. The present bilayer system shows significant modifications in Jc, as evidenced by the suppressed decay of its temperature dependence, as well as the crossing behavior of the magnetic field dependence of Jc at high temperatures. This indicates that enhanced flux pinning emerges at high temperatures, and it is believed to arise from the special magnetic inhomogeneity, i.e., the ferromagnet/antiferromagnet clusters caused by phase separation due to the epitaxial stress between LSMO and the substrate
Poly[[aqua(μ2-oxalato)(μ2-2-oxidopyridinium-3-carboxylato)holmium(III)] monohydrate]
In the title complex, {[Ho(C2O4)(C6H4NO3)(H2O)]·(H2O)}n, the HoIII ion is coordinated by three O atoms from two 2-oxidopyridinium-3-carboxylate ligands, four O atoms from two oxalate ligands and one water molecule in a distorted bicapped trigonal-prismatic geometry. The 2-oxidopyridinium-3-carboxylate and oxalate ligands link the HoIII ions into a layer in (100). These layers are further connected by intermolecular O—H⋯O hydrogen bonds involving the coordinated water molecules to assemble a three-dimensional supramolecular network. The uncoordinated water molecule is involved in N—H⋯O and O—H⋯O hydrogen bonds within the layer
Poly[bis(4,4′-bipyridine)(μ3-4,4′-dicarboxybiphenyl-3,3′-dicarboxylato)iron(II)]
In the polymeric title complex, [Fe(C16H8O8)(C10H8N2)2]n, the iron(II) cation is coordinated by four O atoms from three different 4,4′-dicarboxybiphenyl-3,3′-dicarboxylate ligands and two N atoms from two 4,4′-bipyridine ligands in a distorted octahedral geometry. The 4,4′-dicarboxybiphenyl-3,3′-dicarboxylate ligands bridge adjacent cations, forming chains parallel to the c axis. The chains are further connected by intermolecular O—H⋯N hydrogen bonds, forming two-dimensional supramolecular layers parallel to (010)
Poly[diaqua-μ-oxalato-μ-pyrazine-2-carboxylato-lanthanum(III)]
In the title complex, [La(C5H3N2O2)(C2O4)(H2O)2]n, the LaIII ion is coordinated by one N and three O atoms from two pyrazine-2-carboxylate ligands, by four O atoms from two oxalate ligands and by two O atoms of two water molecules, displaying a distorted bicapped square-antiprismatic geometry. The carboxylate groups of pyrazine-2-carboxylate and oxalate ligands link the lanthanum metal centres, forming layers parallel to (10). The layers are further connected by intermolecular O—H⋯O and N—H⋯O hydrogen-bonding interactions, forming a three-dimensional supramolecular network
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