Pt(111)单晶电极上乙二醇解离吸附反应动力学

运用电化学循环伏安和程序电位阶跃方法研究了乙二醇在Pt(111)单晶电极上的解离吸附过程.动力学研究的定量结果指出,乙二醇解离吸附反应的平均速率随电极电位变化呈火山型分布,其最大值在0.10 V(vs SCE)附近.测得在含2×10－3 mol•L－1乙二醇的溶液中,最大初始解离速率vi为4.35×10－12 mol•cm-－2•s－1.     

On the Soliton Resolution for Equivariant Wave Maps to the Sphere

We consider finite energy corotational wave maps with target manifold . We prove that for a sequence of times, they decompose as a sum of decoupled harmonic maps in the light cone, and a smooth wave map (in the blowup case) or a linear scattering term (in the global case), up to an error which tends to 0 in the energy space. © 2015 Wiley Periodicals, Inc.     

High-resolution spectroscopy and preliminary global analysis of C-H stretching vibrations of C2H4 in the 3000 and 6000 cm regions

Ethylene (ethene, H₂C=CH₂) is a naturally occurring compound in ambient air that affects atmospheric chemistry and global climate. The C₂H₄ spectrum is available in databases only for the 1000 and 3000 cm⁻¹ ranges.In this work, the ethylene absorption spectrum was measured in the 6030-6250 cm⁻¹ range with the use of a high resolution Bruker IFS 125HR Fourier-spectrometer and a two-channel opto-acoustic spectrometer with a diode laser. As a secondary standard of wavelengths, the methane absorption spectrum was used in both cases.A preliminary analysis was realized thanks to the tensorial formalism developed by the Dijon group that is implemented in the XTDS software package [39]. We considered the two combination bands ν₅+ν₉ and ν₅+ν₁₁ as an interacting dyad. Parameters for the ν₉/ν₁₁ dyad were fitted simultaneously from a re-analysis of previously recorded supersonic expansion jet FTIR data, while parameters for the v₅=1 Raman level were taken from literature. More than 600 lines could be assigned in the 6030-6250 cm⁻¹ region (and also 682 in the 2950-3150 cm⁻¹ region) and effective Hamiltonian parameters were fitted, including Coriolis interaction parameters. The dyad features are globally quite well reproduced, even if there are still problems at high J values.     

Assessment of several hybrid DFT functionals for the evaluation of bond length alternation of increasingly long oligomers

We have optimized the ground-state geometry of nine series of increasingly long oligomers, using six hybrid density functionals (O3LYP, B3LYP, B97-1, B98, PBE0, and BHHLYP) combined with three different atomic basis sets. In each case, the obtained bond length alternation (BLA) is compared to the corresponding MP2 values. Three phenomenological categories have been set up. In the first, the BLA exponentially decreases, in which case all the tested functionals give results in very good agreement with MP2. In the second category fall the symmetric oligomers that, due to the Peierls theorem, show large BLA. For these chains, BHHLYP tends to give too large and quickly converging BLA wrt chain length, while O3LYP often leads to the opposite misjudgments, and the remaining hybrids provide valuable results. In the third category, one finds asymmetric compounds presenting significantly unequal bond lengths, for which the divergence between DFT and wave function approaches can be dramatic. Indeed, all hybrids yield too small BLA values, especially for long chain lengths. We also study the effect of chain conformation on the BLA.     

Enhanced heat transfer in confined pool boiling

We report the results of an experimental investigation of the heat transfer during nucleate boiling on a spatially confined boiling surface. The heat flux as a function of the boiling surface temperature was measured in pool boiling pots with diameters ranging from 15 mm down to 4.5 mm. It was found that a reduction of the pool diameter leads to an enhancement of the nucleate boiling heat flux for most of the boiling curve. Our experimental results indicate that this enhancement is not affected by the depth of the boiling pot, the material of the bounding wall, or the diameter of the inlet water supply. High-speed camera imaging shows that the heat transfer enhancement for the spatially confined pool boiling occurs in conjunction with a stable circulating flow, which is in contrast to the chaotic and mainly upward motion for boiling in larger pool diameters. An explanation for the enhancement of the heat transfer and the associated change in flow pattern is found in the singularisation of the nucleate boiling process.     

Influence of the addition of Cr in the microstructure and in the phase transformation temperatures of Cu–Al–Be–Nb–Ni alloys

Journal of Thermal Analysis and Calorimetry - Cu–Al–Be polycrystalline SMAs modified with the addition of inoculants show improved ductility, which accredits them for technological...     

2H( 3He, t)2p reaction at 2 GeV

The exclusive ²H( ³He, t)2p reaction has been studied at 2 GeV for energy transfers up to 500 MeV and triton angles up to 3.4^°. The protons were measured in the large acceptance magnetic detector DIOGENE, in coincidence with the forward tritons detected in a dedicated magnetic arm. The energy transfer spectra extend well above the pion threshold. However, in the region of Δ excitation, the yield is less than 10% of the inclusive ²H( ³He, t) cross-section, which indicates the small contribution of the ΔN ↦ NN process. The angular distributions of the two protons in their center of mass have been analysed as a function of energy transfer and triton angle and a Legendre polynomial decomposition has been achieved. These data have been compared to a model based on a coupled-channel approach for describing the NN and NΔ systems. Received: 21 October 2002 / Accepted: 15 November 2002 / Published online: 11 March 2003 RID="a" ID="a"e-mail: ramstein@ipno.in2p3.fr RID="†" ID="†"Deceased. RID="†" ID="†"Deceased. RID="d" ID="d"Present adress: School of Engineering, J?nk?ping University, P.O. Box 1026, S-551 11 J?nk?ping, Sweden. Communicated by M. Gar?on     

Application of polarized neutron reflectometry and X-ray resonant magnetic reflectometry for determining the inhomogeneous magnetic structure in Fe/Gd multilayers

The evolution of the magnetic structure of multilayer [Fe (35 Å)/Gd (50 Å)₅] with variation in temperature and an applied magnetic field was determined using a complementary approach combining polarized neutron and X-ray resonant magnetic reflectometry. Self-consistent simultaneous analysis of X-ray and neutron spectra allowed us to determine the elemental and depth profiles in the multilayer structure with unprecedented accuracy, including the identification of an inhomogeneous intralayer magnetic structure with near-atomic resolution.