2,751 research outputs found

    Note On Certain Inequalities for Neuman Means

    Full text link
    In this paper, we give the explicit formulas for the Neuman means NAHN_{AH}, NHAN_{HA}, NACN_{AC} and NCAN_{CA}, and present the best possible upper and lower bounds for theses means in terms of the combinations of harmonic mean HH, arithmetic mean AA and contraharmonic mean CC.Comment: 9 page

    Filament L1482 in the California molecular cloud

    Full text link
    Aims. The process of gravitational fragmentation in the L1482 molecular filament of the California molecular cloud is studied by combining several complementary observations and physical estimates. We investigate the kinematic and dynamical states of this molecular filament and physical properties of several dozens of dense molecular clumps embedded therein. Methods. We present and compare molecular line emission observations of the J=2--1 and J=3--2 transitions of 12CO in this molecular complex, using the KOSMA 3-meter telescope. These observations are complemented with archival data observations and analyses of the 13CO J=1--0 emission obtained at the Purple Mountain Observatory 13.7-meter radio telescope at Delingha Station in QingHai Province of west China, as well as infrared emission maps from the Herschel Space Telescope online archive, obtained with the SPIRE and PACS cameras. Comparison of these complementary datasets allow for a comprehensive multi-wavelength analysis of the L1482 molecular filament. Results. We have identified 23 clumps along the molecular filament L1482 in the California molecular cloud. All these molecular clumps show supersonic non-thermal gas motions. While surprisingly similar in mass and size to the much better known Orion molecular cloud, the formation rate of high-mass stars appears to be suppressed in the California molecular cloud relative to that in the Orion molecular cloud based on the mass-radius threshold derived from the static Bonnor Ebert sphere. Our analysis suggests that these molecular filaments are thermally supercritical and molecular clumps may form by gravitational fragmentation along the filament. Instead of being static, these molecular clumps are most likely in processes of dynamic evolution.Comment: 10 pages, 9 figures, 2 tables, accepted to Astronomy and Astrophysic

    Bis(N′-benzoyl­pyridine-4-carbohydrazide)(1,10-phenanthroline)copper(II) dinitrate

    Get PDF
    In the title complex, [Cu(C13H11N3O2)2(C12H8N2)](NO3)2, the CuII atom (site symmetry 2) is coordinated by four N atoms from one 1,10-phenanthroline and two hydrazine ligands, respectively. The hydrazine ligands coordinate to the CuIIatom by a pyridine N atom. These four atoms form a slightly distorted square-planar N4 donor set. In the packing, two additional Cu⋯O inter­actions occur [Cu⋯O = 2.462 (2) Å], resulting in a typical Jahn–Teller-distorted octahedral environment around the Cu atom. N—H⋯O hydrogen bonds result in a three-dimensional network. The O atoms of the anion are disordered over two positions in a 0.68 (2):0.32 (2) ratio

    {N,N-Dimethyl-N′-[phen­yl(2-pyrid­yl)methyl­ene]ethane-1,2-diamine-κ3 N,N′,N′′}dithio­cyanato-κN,κS-copper(II)

    Get PDF
    In the title complex, [Cu(NCS)2(C16H19N3)], the CuII atom is coordinated by a total of four N atoms; three from one tridentate Schiff base ligand and one from one of the NCS− ions. The S atom from the other NCS− ion completes the distorted square-pyramidal coordination

    Aqua[N-(2,5-dihydroxybenzyl)imino­diacetato]copper(II)

    Get PDF
    The title complex, [Cu(C11H11NO6)(H2O)], contains a CuII atom in a distorted square-pyramidal geometry. The metal centre is coordinated in the basal sites by one water mol­ecule and two carboxyl­ate O atoms and one N atom of the tetra­dentate ligand [Cu—O range, 1.9376 (11)–1.9541 (12), Cu—N, 1.9929 (12) Å] while the apical site is occupied by a hydro­quinone O donor atom [Cu—O, 2.3746 (12) Å]. Inter­molecular hydrogen bonding inter­actions involving both hydro­quinone hydr­oxy groups and the coordinated water as donors give a three-dimensional framework structure
    corecore