Since its birth in Britain in the late 1970s, critical discourse analysis （CDA, for short） has attracted great attention of western linguists. At present, some scholars in our country have devoted themselves to the ...Since its birth in Britain in the late 1970s, critical discourse analysis （CDA, for short） has attracted great attention of western linguists. At present, some scholars in our country have devoted themselves to the study of CDA and the study results are rewarding. However, some insufficiencies do exist in the research, such as the over-simplification of theories, excessive attention paid to theories rather than practice and neglect of nurturing critical thinking etc. Therefore, the author proposes to associate CDA with cognitive linguistics and interpret the research methods and the practical values of CDA in a wholly new perspective in terms of the analysis of the cohesion of the cognitive schema, ideology and notions from the information receivers and senders.展开更多
The char combustion mechanisms were analyzed and a comprehensive fractal char combustion model was developed to give a better understanding and better predictions of the char combustion characteristics. Most of the co...The char combustion mechanisms were analyzed and a comprehensive fractal char combustion model was developed to give a better understanding and better predictions of the char combustion characteristics. Most of the complex factors affecting the char combustion were included, such as the coupling effects between the pore diffusion and the chemical reactions, the evolution of the char pore structures and the variation of the apparent reaction order during combustion, the CO/CO_2 ratio in the combustion products and the correction for oxy-char combustion. Eleven different chars were then combusted in two drop tube furnaces with the conversions of the partly burned char samples measured by thermogravimetric analysis. The combustion processes of these chars were simulated with the predicted char conversions matching very well with the measured data which shows that this char combustion model has good accuracy. The apparent reaction order of the char combustion decreases, stabilizes and then increases during the combustion process. The combustion rates in the oxy-mode are generally slower than in the air-mode and the effect of the char-CO_2 gasification reaction becomes obvious only when the temperature is relatively high and the O_2 concentration is relatively low.展开更多
文摘Since its birth in Britain in the late 1970s, critical discourse analysis （CDA, for short） has attracted great attention of western linguists. At present, some scholars in our country have devoted themselves to the study of CDA and the study results are rewarding. However, some insufficiencies do exist in the research, such as the over-simplification of theories, excessive attention paid to theories rather than practice and neglect of nurturing critical thinking etc. Therefore, the author proposes to associate CDA with cognitive linguistics and interpret the research methods and the practical values of CDA in a wholly new perspective in terms of the analysis of the cohesion of the cognitive schema, ideology and notions from the information receivers and senders.
基金Supported by the National Natural Science Foundation of China(No.51176096)
文摘The char combustion mechanisms were analyzed and a comprehensive fractal char combustion model was developed to give a better understanding and better predictions of the char combustion characteristics. Most of the complex factors affecting the char combustion were included, such as the coupling effects between the pore diffusion and the chemical reactions, the evolution of the char pore structures and the variation of the apparent reaction order during combustion, the CO/CO_2 ratio in the combustion products and the correction for oxy-char combustion. Eleven different chars were then combusted in two drop tube furnaces with the conversions of the partly burned char samples measured by thermogravimetric analysis. The combustion processes of these chars were simulated with the predicted char conversions matching very well with the measured data which shows that this char combustion model has good accuracy. The apparent reaction order of the char combustion decreases, stabilizes and then increases during the combustion process. The combustion rates in the oxy-mode are generally slower than in the air-mode and the effect of the char-CO_2 gasification reaction becomes obvious only when the temperature is relatively high and the O_2 concentration is relatively low.
