Formation of p-terphenyl excited states in the ionic liquid methyltributylammonium bis[(trifluoromethyl)sulfonyl]imide: pulse radiolysis study

Solutions of 80 mM benzophenone (BP) and up to 14 mM p-terphenyl (TP) in the ionic liquid methyltributylammonium bis[(trifluoromethyl)sulfonyl]imide (R₄NNTf₂) have been investigated by nanosecond pulse radiolysis. The resulting transient absorption spectra of pulse-irradiated argon saturated solutions correspond to the formation of several intermediates derived from BP and TP: benzophenone radical anion [(C₆H₅)₂CO]^•− (BP^•−) converted after ~20 μs into ketyl radicals (C₆H₅)₂C^•OH (BP^•H), a hydrogen adduct to the phenyl ring of benzophenone C₆H₅COC₆H₆^•, p-terphenyl triplet excited state ³TP*, and traces of TP radical ions. ³TP* was formed in two steps, the first immediately during the pulse and the second in pseudo-first order process with a second order reaction rate constant calculated from TP concentration dependence: k = ~2 × 10⁸ dm³ mol⁻¹ s⁻¹.     

Reversible and Bijectively Related Posets

Call a poset reversible if every of its order-preserving self-bijections is an automorphism. Call two posets bijectively related if from each of the two posets exists an order-preserving bijection to the other. We present two examples of pairs of non-isomorphic, bijectively related posets and an example of a non-reversible poset that is bijectively related only to itself. Also, three classes of reversible posets are described and a sufficient condition for an order-preserving bijection to be an isomorphism is presented.     

Locally accessible information: how much can the parties gain by cooperating?

We investigate measurements of bipartite ensembles restricted to local operations and classical communication and find a universal Holevo-like upper bound on the locally accessible information. We analyze our bound and exhibit a class of states which saturate it. Finally, we link the bound to the problem of quantification of the nonlocality of the operations necessary to extract locally inaccessible information.     

Relativistic turbulence: a long way from preheating to equilibrium

We study, both numerically and analytically, the development of equilibrium after preheating. We show that the process is characterized by the appearance of Kolmogorov spectra and the evolution towards thermal equilibrium follows self-similar dynamics. Simplified kinetic theory gives values for all characteristic exponents which are close to what is observed in lattice simulations. The resulting time for thermalization is long, and temperature at thermalization is low, T approximately 100 eV in the simple lambdaPhi(4) inflationary model. Our results allow a straightforward generalization to realistic models.     

On the piano movers' problem: V. The case of a rod moving in three-dimensional space amidst polyhedral obstacles

This paper, a fifth in a series, solves some additional 3-D special cases of the ?piano movers”? problem, which arises in robotics. The main problem solved in this paper is that of planning the motion of a rod moving amidst polyhedral obstacles. We present polynomial-time motion-planning algorithms for this case, using the connectivity-graph technique described in the preceding papers. We also study certain more general polyhedral problems, which arise in the motion planning problem considered here but have application to other similar problems. Application of these techniques to the problem of planning the motion of a general polyhedral body moving in 3-space amidst polyhedral obstacles is also described.     

Spatial uniformity of group delay in the IR diode radiation attained by short segment of optical fibre application

A simple method for obtaining high uniformity of group delay in the IR diode radiation by means of a short segment of optical fibre attachment is decribed and the results are presented.The experiments were done with edge emitting IR diode structures of over 3 ns ascertained group delay spatial inhomogeneity which, after application of the optical fibre decreased to below the 0.1 ns level.     

A quantal many-body approach to atom-polyatomic collisions

Atom—polyatomic collision rates are discussed, paying particular attention to the multicenter nature of the intermolecular forces. A useful transition rate expression for energy loss shows the central role played by the space—time pair correlation functions of the target.