ABSTRACT
In course recording, the audio recorded in different pickups and environments can be clearly distinguished and cause style differences after splicing, which influences the quality of recorded courses. A common way to improve the above situation is to use voice style unification. In the present study, we propose a voice style unification model based on generated adversarial networks (VSUGAN) to transfer voice style from the spectrogram. The VSUGAN synthesizes the audio by combining the style information from the audio style template and the voice information from the processed audio. And it allows the audio style unification in different environments without retraining the network for new speakers. Meanwhile, the current VSUGAN is implemented and evaluated on THCHS-30 and VCTK-Corpus corpora. The source code of VSUGAN is available at https://github.com/oy-tj/VSUGAN . In one word, it is demonstrated that the VSUGAN can effectively improve the quality of the recorded audio and reduce the style differences in kinds of environments.
ABSTRACT
In order to improve the total sulfur removal rate in coal combustion, an acidic ionic liquid (IL) 1-carboxymethyl-3-methylimidazolium hydrogen sulfate ([HOOCCH2mim][HSO4]) as the extractant combined with the oxidant 30% hydrogen peroxide (H2O2) was applied to reduce the total sulfur content, and its microscopic mechanism of desulfurization was analyzed. The experimental results show that the desulfurization rate of the [HOOCCH2mim][HSO4]-H2O2 (1:10) solution was 45.12% and the organic sulfur removal rate was 16.26%, which were significantly higher than those of only H2O2 or pure [HOOCCH2mim][HSO4]. Fourier-transform infrared (FTIR) spectroscopy and X-ray photoelectron spectroscopy analyses showed that the mercaptan -SH and disulfide -S-S- in coal decreased after being treated with IL-H2O2. In particular, the results of FTIR spectroscopy indicated that the relative proportion of -S-S-and -SH treated with IL-H2O2 (1:10) decreased by 31.9 and 27.2%, respectively, compared with that of a pure IL. This is due to H2O2 oxidation; -SH and -S-S- were oxidized to sulfoxide and then the sulfoxide transferred from the coal phase to the IL phase, which improved organic sulfur removal from coal. Therefore, the combination of an ionic liquid and H2O2 could increase the total desulfurization rate. In addition, the thermogravimetric analysis of coal is divided into four different stages; the weight loss during the combustion stage and the residues show that the IL-H2O2 could improve the coal combustion because of good previous swelling and destruction of bridge bonds and hydrogen bonding of coal. Besides, the fewer residues in IL-H2O2-treated coals also indicate that a less amount of inorganic substance is left in coal after IL-H2O2 desulfurization, which is consistent with the desulfurization results.
ABSTRACT
The SO2 solubility in ionic liquids and absorption mechanisms with different functionalities, including ether, halide, carboxylate, dicarboxylate, thiocynate, phenol, amino, azole groups, etc., are presented in this review. Strategies of improving SO2 capture with low binding energy and the separation performance from CO2 are also concluded. Generally, moderate basicity is favourable for enhancing SO2 capacity and the water (below 6 wt%) effect on absorption is indefinite but generally slight. Introducing electron-withdrawing substituents such as nitrile, halogen, aldehyde and carboxylic groups are proposed to decrease the chemical absorption enthalpy between ionic liquid and SO2 in order to reduce regeneration power consumption. Although it is promising, the absorption enthalpy is still much higher than the physisorption performance especially of the ether-functionalized ones. The biocompatible choline-based, betaine-based, and amino acid ionic liquids have clear trends to be applied in SO2 capture due to their biodegradability, nontoxicity and easy accessibility. Generally, comparing to the traditional solvents, ionic liquids have made great improvement in SO2 capacity, however, the high viscosity and desorption energy are two main obstacles for SO2 absorption and separation. Molecular simulations have been applied to reveal the absorption regimes involving the roles of basic functionalities and physical interactions especially the hydrogen bonds, which could be referred for structure designing of the available ionic liquids with readily fluid characteristics and absorption ability.
