Search results for "BD"
showing 10 items of 3363 documents
Search for the decayB¯0→Λc+p¯pp¯
2014
We report a search for the decay B^0 → Λ^+_cppp. Using a data sample of 471×10^6 BB pairs collected with the BABAR detector at the PEP-II2 storage ring at SLAC, we find no events and set an upper limit on the branching fraction B(B^0 → Λ^+_cppp)×^(B(Λ^+_c→pK^−π^+))_(0.050) <2.8×10^(−6) at 90% C.L., where we have normalized B(Λ^+_c → pK^−π^+) to the world average value.
<p class="HeadingRunIn"><strong><em>Charybdis glaucophylla</em> (Asparagaceae), a new species from Sardinia</strong><…
2012
Charybdis glaucophylla (Asparagaceae), a new species from Sardinia, is described and illustrated. It is a diploid species with 2n = 20 chromosomes growing along the rocky coast, sandy dunes and mountain top in the south-western part of the island. Within the genus, this species results taxonomically well isolated and differentiated due to relevant morphological and phenological features, such as the leaves wide and short, very rigid and glaucous-pruinose, as well as the very late foliation (winter). It shows only some relationships with C. pancration for the whitish bulb tunics and the diploid chromosome complement, and with C. maura and C. aphylla due to the glaucous leaves.
Direct identification of 103–107Mo by a rapid chemical separation procedure
1977
Abstract The nuclides 103–107Mo have been identified by means of γ-ray spectroscopy after the separation of molybdenum from fission products of 235U and 239Pu by a rapid chemical procedure. Half-lives of 67.5 ± 1.5 s for 103Mo, 59.4 ± 0.8 s for 104Mo, 36.7 ± 1.0 s for 105Mo, 8.4 ± 0.5 s for 106Mo and 3.5 ± 0.5 s for 107Mo have been determined and the main γ-lines were assigned to the decay of these isotopes. Some evidence for 108Mo with a half-life ≤2 s has also been obtained.
Effects of substitutions on cyclopentadienyl rings in complexes with molybdenum-mercury bonds. 95Mo and 199Hg NMR studies
1995
NMR data for 95Mo and 199Hg nuclei have been obtained for new di- and trimetallic complexes Cp′(CO)3MoHgX containing molybdenum-mercury bonds and bulky and/or potentially bifunctional substituted cyclopentadienyl ligands; Cp′=C5HMe2Ph2, C5Me4Bz, C5Bz5, C5H4PPh2 and C5Me4PPh2 (Bz=CH2C6H5; Me =CH3; Ph=C6H5); X=Cp′(CO)3Mo, Cl, Br, 1, SCN. They are discussed within the context of our earlier results reported for analogous complexes with the cyclopentadienyl ligands bearing methyl groups. With the exception of phenyl substituted rings, a rather narrow range of 95Mo chemical shifts is found for the compounds with the same number of different substituents on cyclopentadienyl ligands. An outstandin…
The role of molybdenum in Mo-doped V–Mg–O catalysts during the oxidative dehydrogenation of n-butane
1999
Abstract A detailed study on the influence of the addition of molybdenum ions on the catalytic behaviour of a selective vanadium–magnesium mixed oxide catalyst in the oxidation of n-butane has been performed. The catalysts have been prepared by impregnation of a calcined V–Mg–O mixed oxides (23.8 wt% of V2O5) with an aqueous solution of ammonium heptamolybdate, and then calcined, and further characterised by several physico-chemical techniques, i.e. SBET, XRD, FTIR, FT-Raman, XPS, H2-TPR. MgMoO4, in addition to Mg3V2O8 and MgO, have been detected in all the Mo-doped samples. The incorporation of molybdenum modifies not only the number of V5+-species on the catalyst surface and the reducibil…
MoO (x≤2) ultrathin film growth from reactions between metallic molybdenum and TiO2 surfaces
2001
Abstract Exposures to oxygen at room temperature and annealings under vacuum were carried out on deposits obtained from molybdenum interacting with (1 1 0) TiO 2 surfaces in order to obtain molybdenum oxide ultra thin films. Exposures to oxygen at room temperature show that the interfacial molybdenum oxide layers resulting from the TiO 2 /Mo interactions are inactive towards oxygen whereas the metallic molybdenum clusters, which grew on top of the interfacial layers, oxidise into MoO 3 . Besides, during annealings under vacuum, substrate oxygen anions can diffuse into the deposit. Thus, between 400 and 500°C, molybdenum oxide layers are progressively oxidised into MoO 2 . Moreover, from the…
Reactivity between molybdenum and TiO2(110) surfaces: evidence of a sub-monolayer mode and a multilayer mode
2005
Small amounts of molybdenum (from 0.03 to 1.3 eqML) were deposited on non-stoichiometric TiO 2 (1 1 0) surface. The deposits were investigated by means of LEED and X-ray/UV photoemission using synchrotron radiation. For the smallest coverage (<0.2 eqML), deposition leads to oxidation of molybdenum into species close to Mo 4+ .In such a case, states appearing in TiO 2 band gap are mainly due to reduced titanium. For higher coverages, metallic behaviour of molybdenum is observed. This phenomenon was explained, thanks to first principle calculations, as a decrease of the Mo-O interactions for the benefit of the Mo-Mo interactions as the surface molybdenum atom density increases.
Analytic first derivatives for a spin-adapted open-shell coupled cluster theory: Evaluation of first-order electrical properties
2014
An analytic scheme is presented for the evaluation of first derivatives of the energy for a unitary group based spin-adapted coupled cluster (CC) theory, namely, the combinatoric open-shell CC (COSCC) approach within the singles and doubles approximation. The widely used Lagrange multiplier approach is employed for the derivation of an analytical expression for the first derivative of the energy, which in combination with the well-established density-matrix formulation, is used for the computation of first-order electrical properties. Derivations of the spin-adapted lambda equations for determining the Lagrange multipliers and the expressions for the spin-free effective density matrices for…
Embden-Meyerhof-Parnas Pathway
2011
Oxidomolybdenum(IV), ‐(V), ‐(VI) Complexes with Relevance to Molybdenum Enzymes: Oxygen Atom Transfer, Redox Chemistry and EPR Spectroscopy
2010
The cis-dioxidomolybdenum(VI) complex Mo(NN′)2O2 (1) [(NN′) = N-(4-hydroxyphenyl)-2-pyrrolatocarbaldimine] transfers one oxygen atom to phosphanes PMenPh3–n (n = 0–3) to give quantitatively the respective phosphane oxides OPMenPh3–n (OAT, oxygen atom transfer). The kinetics of these OAT reactions has been investigated spectrophotometrically. When offering excess PMenPh3–n (n = 1–3), oxido(phoshane)molybdenum(IV) complexes Mo(NN′)2O(PMenPh3–n) 5a–5c are isolated and characterized by multinuclear NMR spectroscopy (1H, 13C, 31P, 15N), IR spectroscopy, UV/Vis spectroscopy and mass spectrometry. The redox chemistry of the molybdenum(IV) complexes 5a–5c and of molybdenum(VI) complex 1 has been pr…