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381.
Franziska Hess Attila Farkas Ari P. Seitsonen Herbert Over 《Journal of computational chemistry》2012,33(7):757-766
First principles‐based kinetic Monte Carlo (kMC) simulations are performed for the CO oxidation on RuO2(110) under steady‐state reaction conditions. The simulations include a set of elementary reaction steps with activation energies taken from three different ab initio density functional theory studies. Critical comparison of the simulation results reveals that already small variations in the activation energies lead to distinctly different reaction scenarios on the surface, even to the point where the dominating elementary reaction step is substituted by another one. For a critical assessment of the chosen energy parameters, it is not sufficient to compare kMC simulations only to experimental turnover frequency (TOF) as a function of the reactant feed ratio. More appropriate benchmarks for kMC simulations are the actual distribution of reactants on the catalyst's surface during steady‐state reaction, as determined by in situ infrared spectroscopy and in situ scanning tunneling microscopy, and the temperature dependence of TOF in the from of Arrhenius plots. © 2012 Wiley Periodicals, Inc. 相似文献
382.
We propose a method to dynamically generate and control the flow of spin-entangled electrons, each belonging to a spin singlet, by means of adiabatic quantum pumping. The pumping cycle functions by periodic time variation of localized two-body interactions. We develop a generalized approach to adiabatic quantum pumping as traditional methods based on a scattering matrix in one dimension cannot be applied here. We specifically compute the flow of spin-entangled electrons within a Hubbard-like model of quantum dots, discuss possible implementations, and identify parameters that can be used to control the singlet flow. 相似文献
383.
We analyze the modulation of the Stokes parameters in Young's two-pinhole interference experiment with a random electromagnetic beam. We demonstrate that the electromagnetic (spectral) degree of coherence put forward in Opt. Lett.29, 328 (2004) [or its space-time analog in Opt. Express 11, 1137 (2003)] is physically related to the contrasts of modulation in the four Stokes parameters. More explicitly, the electromagnetic degree of coherence is a measure of both the visibility of the intensity fringes and the modulation contrasts of the three polarization Stokes parameters. We also show that by using suitable wave plates the modulation in any Stokes parameter can be transformed into the form of intensity variation, and hence the electromagnetic degree of coherence can be obtained experimentally by four visibility measurements. 相似文献
384.
385.
Rui Gusm?o Cristina Ari?o José Manuel Díaz-Cruz Miquel Esteban 《Analytical and bioanalytical chemistry》2009,394(4):1137-1145
Multivariate curve resolution with alternating least squares (MCR-ALS) has been applied to voltammetric data obtained from
analysis of the competitive binding of cysteine (Cys) and cysteine–glycine (Cys-Gly) by Cd(II) as a first approach towards
mixtures of phytochelatins and related compounds in natural media. From different starting points, the possibilities of formation
of mixed complexes and/or displacements between ligands are investigated. Analysis of the resulting unitary voltammograms
and concentration profiles of the resolved components by MCR-ALS suggests that the strongest ligand (Cys-Gly) is able to displace
the weakest (Cys) from its metal complexes, whereas this does not happen in the opposite direction. On the other hand, no
evidence of Cd mixed-ligand complexes was found.
Figure Differential pulse polarograms measured in the independent titrations of 1 × 10-5 mol L-1 Cys, 1 × 10-5 mol L-1 Cys-Gly, and a mixture of Cys-Gly (0.5 × 10-5 mol L-1) and Cys (1 × 10-5 mol L-1) with Cd2+, at TRIS-HNO3 buffer (0.1 mol L-1 and PH 7.5) in the presence of 0.1 mol L-1 KNO3 相似文献
386.
We report the lasing performance and photobleaching of gain material containing a water solution of Rhodamine 6G dye and gold nanoparticles (NPs). In comparison to a pure dye solution, the investigated material demonstrated both enhancement and quenching of the lasing output, depending on the relative concentration of the gold NPs. Although the presence of NPs with an optimized concentration looks preferable in terms of the lasing output enhancement, such additives deteriorate the operational resource of the gain material; i.e., the photobleaching rate speeds up. 相似文献
387.
We study polarization-dependent transmission of light through arrays of single-slit split-ring resonator (SSRR) based systems at normal incidence using finite integration time domain (FITD) and finite element methods (FEM). It is found that a conventional planar array of SSRRs acts as an effective optical wave plate at certain polarizations of incident light. The effect is attributed to the intrinsic linear birefringence of individual SSRRs. A comparison is made with other split-ring resonator-based systems exhibiting wave-plate-like properties due to inter-SSRR coupling. 相似文献
388.
Tingting Han Tao Song Shiyu Gan Dongxue Han Johan Bobacka Li Niu Ari Ivaska 《中国化学》2023,41(2):207-213
The analytical performance of H+-selective solid-contact ion-selective electrodes (SCISEs) based on solid contact polyaniline doped with chloride (PANI(Cl)) and poly(3,4-ethylenedioxythiophene) doped with poly(styrene sulfonate) (PEDOT(PSS)) was characterized by a developed coulometric signal transduction method. PEDOT(PSS) solid contact is covered by PVC based H+-selective membrane. The obtained coulometric signal demonstrates that the cumulated charge can be amplified by increasing the capacitance of solid contact. SCISEs covered with spin-coated membrane behave faster amperometric response than electrodes with drop-cast membrane. In contrast to earlier works, the amperometric response and impedance spectrum demonstrates H+ transfer through SCISEs is independent from the thickness of membrane. The exceptional behavior of PANI(Cl) H+-SCISEs shows that the capacitance estimated from impedance spectrum at low frequency 10 mHz and coulometric signal of PANI(Cl) based SCISEs is influenced by the applied potentials, whereas PEDOT(PSS) solid contact is independent from the chosen applied potentials. Furthermore, preliminary investigations of coulometric signal transduction on flexible pH sensor implies its potential applications in wearable sensors for sweat ion concentration detection. 相似文献