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841.
Osamu Takahashi Tetsuo Nomura Kiyohiko Tabayashi Katsuyoshi Yamasaki 《Chemical physics》2008,351(1-3):7-12
We performed spectral analysis by using the maximum entropy method instead of the traditional Fourier transform technique to investigate the short-time behavior in molecular systems, such as the energy transfer between vibrational modes and chemical reactions. This procedure was applied to direct ab initio molecular dynamics calculations for the decomposition of formic acid. More reactive trajectories of dehydrolation than those of decarboxylation were obtained for Z-formic acid, which was consistent with the prediction of previous theoretical and experimental studies. Short-time maximum entropy method analyses were performed for typical reactive and non-reactive trajectories. Spectrograms of a reactive trajectory were obtained; these clearly showed the reactant, transient, and product regions, especially for the dehydrolation path. 相似文献
842.
A third-order analytical solution for the gravity–capillary standing wave is derived in Lagrangian coordinates through the Lindstedt–Poincare perturbation method. By numerical computation, the dynamical properties of nonlinear standing waves with surface tension in finite water depth, including particle trajectory and surface profile are investigated. We find that the presence of surface tension leads to a change of the crest form. Moreover, we also find that the particle trajectories near the surface oscillate back and forth along the arcs which will change from concave to convex as the inverse Bond number increases. There is no mass transport of the particles in a wave period. 相似文献
843.
The vector correlations between products and reagents for the reactions Ne+H + 2 , Ne+D + 2 , and Ne+T + 2 are calculated by means of the quasi-classical trajectory method on a new potential energy surface constructed by Lü et al. [J. Chem. Phys. 2010 132, 014303]. The polarization-dependent differential cross-sections (2π/σ)(dσ 00 /dω t ), (2π/σ)(dσ 20 /dω t ), (2π/σ)(dσ 22+ /dω t ), and (2π/σ)(dσ 21 /dω t ), and the distributions of P (θ r ), P (φ r ), and P (θ r ,φ r ) are calculated. The isotopic effect, which is associated with the difference in mass factor among the three reactions, is revealed. 相似文献
844.
Stereodynamics of the reactions Ne+H<sub>2</sub><sup>+</sup>/Ne+D<sub>2</sub><sup>+</sup>/Ne+T<sub>2</sub> 下载免费PDF全文
The vector correlations between products and reagents for the reactions Ne+H + 2 , Ne+D + 2 , and Ne+T + 2 are calculated by means of the quasi-classical trajectory method on a new potential energy surface constructed by Lü et al. [J. Chem. Phys. 2010 132, 014303]. The polarization-dependent differential cross-sections (2π/σ)(dσ 00 /dω t ), (2π/σ)(dσ 20 /dω t ), (2π/σ)(dσ 22+ /dω t ), and (2π/σ)(dσ 21 /dω t ), and the distributions of P (θ r ), P (φ r ), and P (θ r ,φ r ) are calculated. The isotopic effect, which is associated with the difference in mass factor among the three reactions, is revealed. 相似文献
845.
Theoretical studies on the dynamics of the exchange reaction H′ + BrH (ν = 0, j = 0) → H′Br + H are performed on potential energy surface (PES) (Kurosaki et al., private communication) for the ground state using the quasi-classical trajectory method. The cross sections, computed at the collision energies (Ec) of 0.5-2.0 eV, are in good agreement with the earlier quantum wave packet results. The rotational, vibrational, and translational fractions in the total energy and the vibrational distribution for the product molecule are calculated at the same collision-energy range. The results support the repulsive character of the PES. In the considered Ec range, it has little chance to occur in an indirect reaction. The alignment and orientation of the product H′Br are investigated in detail with stereodynamics. The results show that Ec can effect on both the alignment and the orientation of product. 相似文献
846.
High gradient magnetic field separators have been widely used in a variety of biological applications. Recently, the use of magnetic separators to remove malaria-infected red blood cells (pRBCs) from blood circulation in patients with severe malaria has been proposed in a dialysis-like treatment. The capture efficiency of this process depends on many interrelated design variables and constraints such as magnetic pole array pitch, chamber height, and flow rate. In this paper, we model the malaria-infected RBCs (pRBCs) as paramagnetic particles suspended in a Newtonian fluid. Trajectories of the infected cells are numerically calculated inside a micro-channel exposed to a periodic magnetic field gradient. First-order stiff ordinary differential equations (ODEs) governing the trajectory of particles under periodic magnetic fields due to an array of wires are solved numerically using the 1st to 5th order adaptive step Runge-Kutta solver. The numerical experiments show that in order to achieve a capture efficiency of 99% for the pRBCs it is required to have a longer length than 80 mm; this implies that in principle, using optimization techniques the length could be adjusted, i.e., shortened to achieve 99% capture efficiency of the pRBCs. 相似文献
847.
We continue with the exponentiation analysis of multivalued maps defined on Banach spaces. In Part I of this work we have explored the Maclaurin exponentiation technique which is based on the use of a suitable power series. Now we focus the attention on the so-called recursive exponentiation method. Recursive exponentials are specially useful when it comes to study the reachable set associated to a differential inclusion of the form . The definition of the recursive exponential of uses as ingredient the set of trajectories associated to the discrete time system . Although we are taking inspiration from a recent paper by Alvarez et al. [1] on the relation between continuous and discrete time evolution systems, our analysis and results go far beyond the particular context of convex processes considered by these authors. 相似文献
848.
I. N. Medvedev G. A. Mikhailov 《Computational Mathematics and Mathematical Physics》2009,49(3):428-438
Various weighted algorithms for numerical statistical simulation are formulated and studied. The trajectory of an algorithm branches when the current weighting factor exceeds unity. As a result, the weight of an individual branch does not exceed unity and the variance of the estimate for the computed functional is finite. The unbiasedness and finiteness of the variance of estimates are analyzed using the recurrence “partial“ averaging method formulated in this study. The estimation of the particle reproduction factor and solutions to the Helmholtz equation are considered as applications. The comparative complexity of the algorithms is examined using a test problem. The variances of weighted algorithms with branching as applied to integral equations with power nonlinearity are analyzed. 相似文献
849.
GATSONIS Constantine 《中国科学 数学(英文版)》2012,55(8):1565-1582
Surveillance to detect cancer recurrence is an important part of care for cancer survivors.In this paper we discuss the design of optimal strategies for early detection of disease recurrence based on each patient’s distinct biomarker trajectory and periodically updated risk estimated in the setting of a prospective cohort study.We adopt a latent class joint model which considers a longitudinal biomarker process and an event process jointly,to address heterogeneity of patients and disease,to discover distinct biomarker trajectory patterns,to classify patients into different risk groups,and to predict the risk of disease recurrence.The model is used to develop a monitoring strategy that dynamically modifies the monitoring intervals according to patients’ current risk derived from periodically updated biomarker measurements and other indicators of disease spread.The optimal biomarker assessment time is derived using a utility function.We develop an algorithm to apply the proposed strategy to monitoring of new patients after initial treatment.We illustrate the models and the derivation of the optimal strategy using simulated data from monitoring prostate cancer recurrence over a 5-year period. 相似文献
850.