Femtosecond real-time probing of reactions. XIV. Rydberg states of methyl iodide

The elementary reaction dynamics of methyl iodide in two Rydberg states leading to an iodine and a methyl radical occur on the femtosecond time scale (M.H. Janssen, M. Dantus, H. Guo, and A.H. Zewail. Chem. Phys. Lett. 214, 281 (1993)). In this article, we consider the dynamics of this elementary process which involves both the Rydberg and valence states. Direct comparisons are made between theory and experiment with special focus on the following observations: large isotope effects, mode dependence of the predissociation rates, and coherence effects. The quantal molecular dynamics in two-dimensions show that the initial wave packet motion occurs along a vibrational mode involving the light atoms accompanied by transitions from the Rydberg state to the repulsive state; subsequent dynamics on the dissociative state lead to the C—I bond cleavage. The theoretical calculations also give the decay behavior of the Rydberg states with lifetimes in agreement with those observed in the femtosecond experiments. Moreover, the large isotope effect in observed predissociation rates of CH3I and CD3I has been successfully reproduced by the same model. The two-dimensional dynamics underscore the shortcomings of a one-dimensional picture in which the C—I serves as the sole reaction coordinate. The model presented here offers a viable mechanism for the dynamics of these Rydberg states

A Direct Method for Computing Higher Order Folds

We consider the computation of higher order fold or limit points of two parameter-dependent nonlinear problems. A direct method is proposed and an efficient implementation of the direct method is presented. Numerical results for the thermal ignition problem are given

Response analysis of an automobile shipping container

The design and development of automobile shipping containers to reduce enroute damage are discussed. Vibration tests were conducted to determine the system structural integrity. A dynamic analysis was made using NASTRAN and the results of the test and the analysis are compared

OWNERSHIP AND INDUSTRIAL POLLUTION CONTROL: EVIDENCE FROM CHINA

This study explores the differences in pollution control performances of industrial enterprises with various ownerships in China - State owned (SOE), collectively or community owned (COE), privately owned (POE), foreign directly invested (FDI) companies as well as joint ventures. A survey was conducted of approximately 1000 industrial firms in three provinces in China, which collects the detailed firm-level information in the year of 1999. Personal interviews of enterprises managers were also conducted in these samples, and subjective information was collected. Analyses have been performed on the differences in receiving and reacting to environmental regulatory enforcement, community pressure, environmental services, and internal environmental management among different ownerships. The determinants of the industrial pollution emissions in China are identified in the econometrical analyses. The results show that FDI and COE have better environmental performances, while SOEs and the POEs in China are the worst.Environmental Economics and Policy,

Application-Oriented Flow Control: Fundamentals, Algorithms and Fairness

This paper is concerned with flow control and resource allocation problems in computer networks in which real-time applications may have hard quality of service (QoS) requirements. Recent optimal flow control approaches are unable to deal with these problems since QoS utility functions generally do not satisfy the strict concavity condition in real-time applications. For elastic traffic, we show that bandwidth allocations using the existing optimal flow control strategy can be quite unfair. If we consider different QoS requirements among network users, it may be undesirable to allocate bandwidth simply according to the traditional max-min fairness or proportional fairness. Instead, a network should have the ability to allocate bandwidth resources to various users, addressing their real utility requirements. For these reasons, this paper proposes a new distributed flow control algorithm for multiservice networks, where the application's utility is only assumed to be continuously increasing over the available bandwidth. In this, we show that the algorithm converges, and that at convergence, the utility achieved by each application is well balanced in a proportionally (or max-min) fair manner

Power-Law Behavior of Bond Energy Correlators in a Kitaev-type Model with a Stable Parton Fermi Surface

We study bond energy correlation functions in an exactly solvable quantum spin model of Kitaev type on the kagome lattice with stable Fermi surface of partons proposed recently by Chua et al, Ref.\[arXiv:1010.1035]. Even though any spin correlations are ultra-short ranged, we find that the bond energy correlations have power law behavior with a $1/|{\bm r}|^3$ envelope and oscillations at incommensurate wavevectors. We determine the corresponding singular surfaces in momentum space, which provide a gauge-invariant characterization of this gapless spin liquid.Comment: 6 pages, 5 figure

Analyses of pion-nucleon elastic scattering amplitudes up to O(p4)O(p^4) in extended-on-mass-shell subtraction scheme

We extend the analysis of elastic pion-nucleon scattering up to $O(p^4)$ level using extended-on-mass-shell subtraction scheme within the framework of covariant baryon chiral perturbation theory. Numerical fits to partial wave phase shift data up to $\sqrt{s}=1.13$ GeV are performed to pin down the free low energy constants. A good description to the existing phase shift data is achieved. We find a good convergence for the chiral series at $O(p^4)$, considerably improved with respect to the $O(p^3)$-level analyses found in previous literature. Also, the leading order contribution from explicit $\Delta(1232)$ resonance and partially-included $\Delta(1232)$ loop contribution are included to describe phase shift data up to $\sqrt{s}=1.20$ GeV. As phenomenological applications, we investigate chiral correction to the Goldberger-Treiman relation %$\Delta_{GT}$ and find that it converges rapidly, and the $O(p^3)$ correction is found to be very small: $\simeq 0.2$. We also get a reasonable prediction of pion-nucleon sigma term $\sigma_{\pi N}$ up to $O(p^4)$ by performing fits including both the pion-nucleon partial wave phase shift data and the lattice QCD data. We report that $\sigma_{\pi N}=52\pm7$ MeV from the fit without $\Delta(1232)$, and $\sigma_{\pi N}=45\pm6$ MeV from the fit with explicit $\Delta(1232)$.Comment: The final version published in Phys.Rev. D 87, 054019 (2013