Two new push-pull type second-order nonlinear optical (NLO) active isophorone-based alkoxysilane dyes with the same acceptor were synthesized and characterized. One silane (ICTES-HEMA) bears a chromophore with a hydroxyethyl methylamino donor and the other silane (ICTES-HMPP) is a bulkier analogue with a hydroxymethyl diphenylamino donor. Transparent, homogeneous films were prepared via the copolymerization of tetraalkoxysilane (TEOS) and different NLO silanes with the ratio of 5:1. The d(33) values obtained for the HEMA and HMPP films are 46.3 and 20.6 pm/V, respectively. Normalized UV-vis spectra reveal that the introduction of a diaryl group would help to prevent unfavorable organization of the chromophores. The reorientation dynamic stabilities of the samples were studied by second-harmonic generation (SHG) measurements, demonstrating that bulkier chromophores incorporated in sol-gel materials would not necessarily lead to higher stabilities over time.
Research
on characterizing and optimizing heat-transfer capacity
(UA), an important design parameter determining separation
efficiency and energy consumption in heat-integrated air separation
columns (HIASC), is presented. The mathematical mechanism model of
HIASC is built first, then characteristics of UA are
explored. It is discovered that on one hand increasing of UA will lead to higher compressor load and thus brings higher
energy consumption; however on the other hand increasing of UA will benefit mass transfer and conversely reduces energy
consumption. For this reason, the optimal design on UA makes available the maximum energy efficiency together with considerable
savings of the equipment investment, which provides guidelines for
further designing of HIASC. Furthermore, an optimal partially coupled
structure of HIASC is developed to exploit energy saving potential
by lowering minimum temperature difference. The obtained optimization
results show that the optimal design of UA for a
fully coupled HIASC has achieved a 41.5% reduction in energy consumption
compared to conventional air separation columns (CASCs) and up to
46.9% energy reduction is achieved by applying the optimal partially
coupled design.
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