New π-Extended Donors: Synthesis,Characterization, Electrochemical and Electrical Conductivity Studies

A new series of tetrathiafulvalene (TTF) molecules with extended π-system was prepared by using a Wittig reaction to generate the TTF key. The process of deprotection-alkylation of thiolates provided access to a wide variety of molecules. The study of their reducing power was carried out by cyclic voltammetry. Charge transfer complexes have also been chemically prepared by using TCNQ as an electron acceptor; the electrical conductivity of their compressed powders shows insulator behavior. The IR spectra of the TCNQ salts were recorded and used to characterize and estimate the degree of charge transfer of these complexes.

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Evidence of the central tetrathiafulvalene bond opening by copper(II) salts. In situ generation of 2,3-bis(2′-cyanoethylchalcogeno)-7,8-benzo-1,4,6,9-tetrathia-10-ceto spiro[4,5]decane

The two-electrons oxidation of 4,5-benzo-6,7-bis(2′-cyanoethylthio) TTF (CETBz-TTF) and 4,5-benzo-6,7-bis(2′-cyanoethylseleno) TTF (CESBz-TTF) with Cu²⁺X₂ (X = Cl⁻, ) leads to the formation of 2,3-bis(2′-cyanoethylchalcogeno)-7,8-benzo-1,4,6,9-tetrathia-10-ceto spiro[4,5]decane after opening of the -C-S- bond of the central TTF core.     

Anthracene‐containing conjugated polymer showing four optical transitions upon doping: A spectroscopic study

An anthracene‐containing poly(arylene‐ethynylene)‐alt‐poly(arylene‐vinylene) (PAE‐PAV) of general constitutional unit (? Ph? C?C? Anthr? C?C? Ph? CH?CH? Anthr? CH?CH)_n bearing two 2‐ethylhexyloxy solubilizing side chains on each phenylene (Ph) unit has been synthesized and characterized. The basic electrochemical characterization was done, showing the existence of two non‐reversible oxidation and one reversible reduction peaks. The optical properties, the real and imaginary part of the dielectric function, were probed using spectroscopic ellipsometry (SE). The vibrational structure of the undoped/doped polymer was investigated using Fourier transformed infrared spectroscopy. A strong change in the polaronic absorption was observed during the doping, which after modeling revealed the existence of two separated transitions. The optical changes upon doping were additionally recorded using the SE technique. Similar to the results from FT‐IR spectroscopy, two new in‐the‐gap absorptions were found. Moreover, the electrical conductivity as well as the mobility of positive carriers were measured. In the undoped state, the conductivity of the polymer was found to be below the detection limit (<μS cm^?1), after doping the conductivity increased to 0.69 S cm^?1. © 2013 Wiley Periodicals, Inc. J. Polym. Sci., Part B: Polym. Phys. 2014 , 52, 338–346     

Strong Stability of the Batch Arrival Queueing Systems

In this work, we use the strong stability method to study the batch arrival queue after a perturbation of the batch size distribution. We show that, under some hypotheses, the characteristics of the batch arrival queueing system M ^X /M/1 may be approximated by the correspondent characteristics of the system M ^Geo /M/1.

After clarifying the conditions of approximation, we obtain stability inequalities with an exact computation of constants.     

An Efficient Parameterized Logarithmic Kernel Function for Semidefinite Optimization

Acta Mathematicae Applicatae Sinica, English Series - In this paper, we present a primal-dual interior point algorithm for semidefinite optimization problems based on a new class of kernel...     

Performance analysis approximation in a queueing system of type M/G/1

In this work, we apply the strong stability method to obtain an estimate for the proximity of the performance measures in the M/G/1 queueing system to the same performance measures in the M/M/1 system under the assumption that the distributions of the service time are close and the arrival flows coincide. In addition to the proof of the stability fact for the perturbed M/M/1 queueing system, we obtain the inequalities of the stability. These results give with precision the error, on the queue size stationary distribution, due to the approximation. For this, we elaborate from the obtained theoretical results, the STR-STAB algorithm which we execute for a determined queueing system: M/Coxian − 2/1. The accuracy of the approach is evaluated by comparison with simulation results.