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51.
R. A. Manzhos B. I. Podlovchenko Yu. M. Maksimov 《Russian Journal of Electrochemistry》2006,42(6):658-664
Transients of the open-circuit potential, which are observed when formic acid is interacting wit adsorbed oxygen (Oads) preliminarily accumulated on polycrystalline “smooth” platinum (pcPt), are measure in an aqueous solution of sulfuric acid. It is shown that, as with platinized platinum (Pt/Pt), at large coverage by adsorbed oxygen (θO = 1?0.8), adsorbed oxygen interacts directly with molecules of formic acid from solution. In the region of medium coverages (θO = 0.8?0.2), on the other hand, a mechanism of “conjugated reactions” is realized. It is established that, in the case of pcPt, the direct interaction of Oads with molecules of HCOOH from solution proceeds slower by nearly three times and the interaction via the mechanism of “conjugated reactions,” faster by about three times, as compared with Pt/Pt. 相似文献
52.
In the present work, corrosion resistance of surface-coated galvanized steel was quantitatively determined by an analysis
of the alternating current (AC) impedance spectra measured on the salt-spray-tested specimen. To evaluate the corrosion resistance
of the surface-coated galvanized steel, AC impedance spectroscopy was performed on the salt-spray-tested specimen previously
exposed to salt-sprayed corrosive environment. From the analysis of the impedance spectra, the area fraction transient of
white rust θ
2(t) was theoretically derived from the equivalent circuit equation by using two fitting parameters. The values of the two fitting
parameters were determined by fitting the empirical transient equations to the area fraction of the resin coating layer and
to the total resistance obtained from the impedance spectra measured, respectively. From the analyses of θ
2(t) for four kinds of surface-coated galvanized steels with various resin coating layers, it is indicated that as the values
of the two fitting parameters decrease in the order of CP, GI, OD and OM (commercial trade names) specimens, the corrosion
resistance increases in that order as well. Furthermore, from the quantitative comparison of the two fitting parameters with
the polarization resistance of the upper resin coating layer R
p determined from the potentiodynamic polarization curve, it is suggested that the two fitting parameters decrease in value
as well with increasing R
p. 相似文献
53.
Using laser flash photolysis/transient absorption technique for the study of two photon photodissociation of carbon disulfide in acetonitrile solution at 266 nm, the transient UV-Vis absorption spectrum of Rydberg state CS2 (6sσg) within 240-370 nm and subsequent dissociation product CS (α^3П) with the maximum absorption at 260 nm were directly observed. The lifetime of CS (α^3П) in the nitrogen and oxygen saturated solution is also studied in our experiment. 相似文献
54.
Wentian Li 《Journal of statistical physics》1992,68(5-6):829-882
Dynamical systems with nonlocal connections have potential applications to economic and biological systems. This paper studies the dynamics of nonlocal cellular automata. In particular, all two-state, three-input nonlocal cellular automata are classified according to the dynamical behavior starting from random initial configurations and random wirings, although it is observed that sometimes a rule can have different dynamical behaviors with different wirings. The nonlocal cellular automata rule space is studied using a mean-field parametrization which is ideal for the situation of random wiring. Nonlocal cellular automata can be considered as computers carrying out computation at the level of each component. Their computational abilities are studied from the point of view of whether they contain many basic logical gates. In particular, I ask the question of whether a three-input cellular automaton rule contains the three fundamental logical gates: two-input rules AND and OR, and one-input rule NOT. A particularly interesting edge-of-chaos nonlocal cellular automaton, the rule 184, is studied in detail. It is a system of coupled selectors or multiplexers. It is also part of the Fredkin's gate—a proposed fundamental gate for conservative computations. This rule exhibits irregular fluctuations of density, large coherent structures, and long transient times. 相似文献
55.
Hwang IW Park M Ahn TK Yoon ZS Ko DM Kim D Ito F Ishibashi Y Khan SR Nagasawa Y Miyasaka H Ikeda C Takahashi R Ogawa K Satake A Kobuke Y 《Chemistry (Weinheim an der Bergstrasse, Germany)》2005,11(12):3753-3761
The excitation-energy-hopping (EEH) times within two-dimensional cyclic zinc(II)-porphyrin arrays 5 and 6, which were prepared by intermolecular coordination and ring-closing metathesis reaction of olefins, were deduced by modeling the EEH process based on the anisotropy depolarization as well as the exciton-exciton annihilation dynamics. Assuming the number of energy-hopping sites N = 5 and 6, the two different experimental observables, that is, anisotropy depolarization and exciton-excition annihilation times, consistently give the EEH times of 8.0 +/- 0.5 and 5.3 +/- 0.6 ps through the 1,3-phenylene linkages of 5 and 6, respectively. Accordingly, the self-assembled cyclic porphyrin arrays have proven to be well-defined two-dimensional models for natural light-harvesting complexes. 相似文献
56.
Fullerenes C60 and C70 have high electron affinity ( 2.6 - 2.8 ev ) and readily form anions on electronchemical reduction1, which were famous as electron acceptor in photo-excitation because of symmetrical shape, large size, and properties of its p - electron system2. After observation of molecular ferromagnetism3 in the tetrakis (dimethylamino ) ethylene salt of C60 as well as the occurrence of ultra-fast photoinduced electron transfer within the dimethyl aniline - C60 complex4, prompted us… 相似文献
57.
He Ping ZENG 《中国化学快报》2002,13(12)
Photoinduced electron transfer processes between fullerenes (C60 / C70) and N, N, N′, N′- tetra - ( p-methylphenyl ) - 4, 4′- diamino - 1, 1′- diphenyl ether ( TPDAE ) have been studied by nanosecond laser flash photolysis. Quantum yields and rate constants of electron transfer from TPDAE to excited triplet state of fullerenes (C60 / C70 ) in benzonitrile have been evaluated by observing the transient absorption bands in the near-IR region where the excited triplet state, radical anion of fullerenes ( C60 / C70 ) and radical cations of TPDAE appear. 相似文献
58.
Dazhang Zhu Shilong Wang Xiaoyu Sun Yaming Ni Side Yao 《Frontiers of Chemistry in China》2007,2(4):354-358
The reaction mechanism between isoquinoline and ·OH radical in aqueous dilute solutions under different conditions was studied
by pulse radiolysis. The main characteristic peaks in these transient absorption spectra were attributed and the growth-decay
trends of several transient species were investigated. Under neutral or alkaline conditions, the reaction of ·OH radical and
isoquinoline produces OH-adducts with respective rate constants of 3.4 × 109 and 6.6 × 109 mol−1 · dm3 · s−1 while under acidic conditions, the isoquinoline was firstly protonated and then ·OH added to the benzene ring and produced
protonated isoquinoline OH-adducts with a rate constant of 3.9 × 109 mol−1 · dm3 · s−1. With a better understanding on radiolysis of isoquinoline, this study is of help for its degradation and for environmental
protection.
__________
Translated from Journal of Fudan University (Natural Science), 2006, 45(6): 774–778 [8BD1;81EA: 590D;65E6;5B66;62A5;(自然科学版)] 相似文献
59.
This paper outlines the development and adaptation of a coupling strategy for transient temperature analysis in a solid via a conjugate heat transfer method. This study proposes a quasi‐dynamic coupling procedure to bridge the temporal disparities between the fluid and the solid. In this approach, dynamic thermal modeling in the solid is coupled with a sequence of steady states in the fluid. This quasi‐dynamic algorithm has been applied to the problem of convective heat transfer over, and transient conduction heat transfer within, a flat plate using the severe thermal conditions of a solid propellant rocket. Two different coupled thermal computations have been performed. In the first one—referred to as the reference computation—the coupling period is equal to the smallest solid time constant. In the second one, a very large coupling period is used. The results show that the procedure can predict accurate transient temperature fields at a reasonable computational cost. The simulation CPU time is approximately reduced by up to 90%, while maintaining a very good accuracy. All the details of the numerical test case are given in the paper. This application illustrates the capabilities and the overall efficiency of this coupled approach in a solid transient problem using long term simulations of time dependent flows. Copyright © 2013 John Wiley & Sons, Ltd. 相似文献
60.
Mass transfer from irregular-shaped naphthalene particles (100-200 inn in size) was studitd in an electrodynamic balance. Charged particles were suspended in an electrostatic field directly in line with a calibrated air jet. Mass and size change histories were obtained under ambient conditions, and under steady- and pulsed-flow conditions. For natural convection, the time-averaged Sherwood number was similar to that for spheres. Forced-convection Sherwood number under steady-flow conditions was strongly dependent on particle shape and panicle Reynolds number, and was consistently higher than values predicted for spheres at comparable Reynolds numbers. This study validates the technique and indicates the shape effect on mass transfer form single particles. 相似文献