The reaction path of CO and Fe2O3 in a chemical-looping combustion system

The reaction mechanism of CO and Fe₂O₃ in a chemical-looping combustion (CLC) was studied based on density functional theory (DFT) at B3LYP level in this paper. The structures of all reactants, intermediate, transition structures and products of this reaction had been optimized and characterized. The reaction path was validated by means of the intrinsic reaction coordinate (IRC) approach. The result showed that the reaction was divided into two steps, the adsorbed CO molecule on Fe ₂O₃ surface formed a medium state with one broken Fe-O bond in step1, and in step2, O atom broken here oxidized a subsequent CO molecule in the fuel reactor. Thus, Fe₂O₃ molecule transport O from air to oxide CO continually in the CLC process. The activation energy and rate coefficients of the two steps were also obtained.

An iterative longest matching segment approach to speech enhancement with additive noise and channel distortion

This paper presents a new approach to speech enhancement from single-channel measurements involving both noise and channel distortion (i.e., convolutional noise), and demonstrates its applications for robust speech recognition and for improving noisy speech quality. The approach is based on finding longest matching segments (LMS) from a corpus of clean, wideband speech. The approach adds three novel developments to our previous LMS research. First, we address the problem of channel distortion as well as additive noise. Second, we present an improved method for modeling noise for speech estimation. Third, we present an iterative algorithm which updates the noise and channel estimates of the corpus data model. In experiments using speech recognition as a test with the Aurora 4 database, the use of our enhancement approach as a preprocessor for feature extraction significantly improved the performance of a baseline recognition system. In another comparison against conventional enhancement algorithms, both the PESQ and the segmental SNR ratings of the LMS algorithm were superior to the other methods for noisy speech enhancement.

A small supramolecular system which emulates the unidirectional, path-selective photoinduced electron transfer (PET) of the bacterial photosynthetic reaction centre (PRC)

The singlet excited state of the 4-aminonaphthalimide fluorophore in 1a and 1b directs electron transfer from intramolecular but external amine groups along only one of two available paths.

National institutions and employers’ age management practices in Britain and Germany:‘Path dependence’and option exploration

We pursue a comparative analysis of employers’ age management practices in Britain and Germany, asking how valid ‘convergence’ and ‘Varieties of Capitalism’ theories are. After rejecting the convergence verdict, we proceed to ask how far ‘path dependence’ helps explain inter-country differences. Through 19 interviews with British and German experts, we find that firms have reacted in different ways to promptings from the EU and the two states. Change has been modest and a rhetoric-reality gap exists in firms as they seek to hedge. We point to continuities in German institutional methods of developing new initiatives, and the emerging role of British NGOs in helping firms and the state develop new options. We argue that ‘path dependence’ offers insight into the national comparison, but also advance the idea of national modes of firm optionexploration as an important way of conceptualizing the processes involved.