9,197 research outputs found
Reinvestigation of ionic conductivity of a layered Li(BH3NH2BH2NH2BH3) salt
No full textWe reinvestigated ionic conductivity of lithium ions for Li(BH3NH2BH2NH2BH3), an ammonia borane derivative. The observed conductivity (4.0x10–6 S/cm at 65°C) was found to be over four orders of magnitude higher than the value reported previously at 70oC for this compound. Since very slow thermal decomposition of Li(BH3NH2BH2NH2BH3) progresses already below 100°C, the previous results reported for 70–130°C most likely correspond to decomposed samples. The activation energy for lithium conductivity of polycrystalline layered Li(BH3NH2BH2NH2BH3) (57 kJ/mol) resembles that for powdered Li3N (59 kJ/mol) suggesting similar mechanism of lithium diffusion in both materials
Photoemission studies of oxygen adsorbed on a LiAl(110) alloy surface: Role of Li segregation
No full textWe investigated that the effect of the number of segregated Li atoms on the rate of oxidation on a LiAl alloy surface. Oxygen molecules adsorbed on the LiAl alloy react with the surface atoms to form stable oxides. The segregated Li atoms at reconstructed surfaces (c(2 x 2) and (2 x 1)) enhance the oxidation rate and form stable LiAlO, and Li2O. The degree of enhancement of oxidation by segregated Li atoms varies as a function Of 02 exposure and annealing temperature, where the latter is directly related to the mode of surface reconstruction by Li segregation. (c) 2005 Elsevier B.V. All rights reserved.KOSEF through the Center for Nanotubes and Nanostructured Composites, the Brain Korea 21 Project, the Advanced Backbone IT Technology Development Project, and the National R & D Project for Nano Science and Technolog
Lupus-related advanced liver involvement as the initial presentation of systemic lupus erythematosus.
No full textConcomitant aseptic subcutaneous abscess and immunoglobulin-mediated nephropathy--rare extra-intestinal manifestations in ulcerative colitis.
No full textTesting the Parametric Specification of the Diffusion Function in a Diffusion Process
Full text linkA new consistent test is proposed for the parametric specification of the diffusion function in a diffusion process without any restrictions on the functional form of the drift function. The data are assumed to be sampled discretely in a time interval that can be fixed or lengthened to infinity. The test statistic is shown to follow an asymptotic normal distribution under the null hypothesis that the parametric diffusion function is correctly specified. Monte Carlo simulations are conducted to examine the finite-sample performance of the test, revealing that the test has good size and power.Econometric and statistical methods; Interest rates
Li+ ion attachment to chloromethyl and chlorofluoromethyl peroxyl radicals: Structures and properties of CHnCl3-nO2-Li+ and CFnCl3-nO2-Li+ (n=0-3) complexes
No full textThe structures and stabilities of these still experimentally unknown CHnCl3-O-n(2)-Li+ and CFnCl3-O-n(2)-Li+ ions have been theoretically investigated by ab initio molecular orbital theory and density functional theory (DFT) in conjunction with the 6-311G(d,p), 6-311+G(d,p), 6-311+G(2d,p) and 6-311+G(2df,2p) basis sets. The optimized geometries, chemical bonding and NBO analysis indicate that these complexes of CHnCl3-nO2-Li+ and CFnCl3-nO2Li+ exist as ion-dipole molecules. The calculated affinity energies of these species exceed 41.9 kJ/mol, which are large enough to suggest the possibility that these tide complexes could be detected as stable species in gas phase by Li+ ion attachment mass spectrometry
Kinetic Study of the Diels–Alder Reaction of Li<sup>+</sup>@C<sub>60</sub> with Cyclohexadiene: Greatly Increased Reaction Rate by Encapsulated Li<sup>+</sup>
No full textWe studied the kinetics of the Diels–Alder
reaction of Li+-encapsulated [60]fullerene with 1,3-cyclohexadiene
and characterized
the obtained product, [Li+@C60(C6H8)](PF6–). Compared with
empty C60, Li+@C60 reacted 2400-fold
faster at 303 K, a rate enhancement that corresponds to lowering the
activation energy by 24.2 kJ mol–1. The enhanced
Diels–Alder reaction rate was well explained by DFT calculation
at the M06-2X/6-31G(d) level of theory considering the reactant complex
with dispersion corrections. The calculated activation energies for
empty C60 and Li+@C60 (65.2 and 43.6
kJ mol–1, respectively) agreed fairly well with
the experimentally obtained values (67.4 and 44.0 kJ mol–1, respectively). According to the calculation, the lowering of the
transition state energy by Li+ encapsulation was associated
with stabilization of the reactant complex (by 14.1 kJ mol–1) and the [4 + 2] product (by 5.9 kJ mol–1) through
favorable frontier molecular orbital interactions. The encapsulated
Li+ ion catalyzed the Diels–Alder reaction by lowering
the LUMO of Li+@C60. This is the first detailed
report on the kinetics of a Diels–Alder reaction catalyzed
by an encapsulated Lewis acid catalyst rather than one coordinated
to a heteroatom in the dienophile
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