A mixing-precipitation model based on the modified coalescence-redispersion model was presented to describe the flow,mixing,nucleation and growth in a rotating packed bed(RPB) .The model was coupled with population ba...A mixing-precipitation model based on the modified coalescence-redispersion model was presented to describe the flow,mixing,nucleation and growth in a rotating packed bed(RPB) .The model was coupled with population balance,mass balance and crystallization kinetics.It predicted well the influence of coalescence prob-ability,which represents the mixing intensity among droplets,on the particle number density,supersaturation and mean particle size of the produced precipitates.The effects of the radial thickness of packing,liquid flow rate and rotating speed on the product particle size were also investigated.The results indicate that the needed radial length of packing is short for sparingly soluble substance precipitation(about 40-50 mm in this work) ,and the mean parti-cle size of precipitates decreases with the increase of rotating speed and liquid flow rate,respectively.The validity of this model was verified by experiment on BaSO4 precipitation in RPB.展开更多
This essay first reviews the history of English writing research in China, focusing on the way that though Chinese students negotiated multiple languages and cultures, nationalism and positivism oriented most teachers...This essay first reviews the history of English writing research in China, focusing on the way that though Chinese students negotiated multiple languages and cultures, nationalism and positivism oriented most teachers and researchers to treating native English speakers as the target audience of student writing. The essay then reviews the research reported in this special issue. These studies have advanced English writing research in China by examining writing at secondary, college, and graduate levels, the multi-dimensional feedback that student writers receive, and identity construction in student texts. The essay concludes by pointing out avenues for future research in this area.展开更多
The aim of this paper is to present the design and experimental validation process for a thermoacoustic looped-tube engine. The design procedure consists of numerical modelling of the system using DELTA EC tool, Desig...The aim of this paper is to present the design and experimental validation process for a thermoacoustic looped-tube engine. The design procedure consists of numerical modelling of the system using DELTA EC tool, Design Environment for Low-amplitude ThermoAcousfic Energy Conversion, in particular the effects of mean pressure and regenerator configuration on the pressure amplitude and acoustic power generated. This is followed by the construction of a practical engine system equipped with a ceramic regenerator - a substrate used in auto- motive catalytic converters with fine square channels. The preliminary testing results are obtained and compared with the simulations in detail.The measurement results agree very well on the qualitative level and are reasonably close in the quantitative sense.展开更多
Metacognition has been divided into information monitoring and control processes. Monitoring involves knowing that you know or do not know some information without taking corrective action. Control involves taking cor...Metacognition has been divided into information monitoring and control processes. Monitoring involves knowing that you know or do not know some information without taking corrective action. Control involves taking corrective action based on the knowledge that you know or do not know some information. In comparative metacognition, considerable attention has been paid toward critically assessing putative evidence for information monitoring in non-human animals. However, less attention has been paid toward critically evaluating evidence for control processes in animals. We briefly review a critique of information-monitoring in animals. Next, we apply these concepts to a number of studies that focus on information seeking in animals. The main type of evidence for control processes in animals come from tube tipping experiments. Before having the opportunity to search for the bait in these experiments, the subject sometimes observes opaque tubes being baited but is sometimes prevented from seeing the baiting. The observations that the subjects look more if baiting was not seen and are more accurate if baiting was seen have been taken as evidence for metacognition in information-seeking experiments. We propose simple alternative hypotheses that are sufficient to explain putative evidence for information seeking in animals without positing metacognition. The alternative explanation focuses on two relatively simple principles： First, an animal has a default ＂look before you go＂ response which supersedes random searches in space. Second, spatially guided behavior follows a default rule of ＂go where something good is.＂ These principles can explain the results of tube tipping experiments without proposing metacognition [Current Zoology 57 （4）： 531-542, 2011].展开更多
基金Supported by the National Natural Science Foundation of China（20821004 20325621） Beijing Municipal Commission of Education（JD100100403）
文摘A mixing-precipitation model based on the modified coalescence-redispersion model was presented to describe the flow,mixing,nucleation and growth in a rotating packed bed(RPB) .The model was coupled with population balance,mass balance and crystallization kinetics.It predicted well the influence of coalescence prob-ability,which represents the mixing intensity among droplets,on the particle number density,supersaturation and mean particle size of the produced precipitates.The effects of the radial thickness of packing,liquid flow rate and rotating speed on the product particle size were also investigated.The results indicate that the needed radial length of packing is short for sparingly soluble substance precipitation(about 40-50 mm in this work) ,and the mean parti-cle size of precipitates decreases with the increase of rotating speed and liquid flow rate,respectively.The validity of this model was verified by experiment on BaSO4 precipitation in RPB.
文摘This essay first reviews the history of English writing research in China, focusing on the way that though Chinese students negotiated multiple languages and cultures, nationalism and positivism oriented most teachers and researchers to treating native English speakers as the target audience of student writing. The essay then reviews the research reported in this special issue. These studies have advanced English writing research in China by examining writing at secondary, college, and graduate levels, the multi-dimensional feedback that student writers receive, and identity construction in student texts. The essay concludes by pointing out avenues for future research in this area.
基金the University of Bahrain for sponsoring the PhD programme of the first authorEPSRC UK for supporting this research under grants GR/T04502/01 and GR/T04519/01
文摘The aim of this paper is to present the design and experimental validation process for a thermoacoustic looped-tube engine. The design procedure consists of numerical modelling of the system using DELTA EC tool, Design Environment for Low-amplitude ThermoAcousfic Energy Conversion, in particular the effects of mean pressure and regenerator configuration on the pressure amplitude and acoustic power generated. This is followed by the construction of a practical engine system equipped with a ceramic regenerator - a substrate used in auto- motive catalytic converters with fine square channels. The preliminary testing results are obtained and compared with the simulations in detail.The measurement results agree very well on the qualitative level and are reasonably close in the quantitative sense.
文摘Metacognition has been divided into information monitoring and control processes. Monitoring involves knowing that you know or do not know some information without taking corrective action. Control involves taking corrective action based on the knowledge that you know or do not know some information. In comparative metacognition, considerable attention has been paid toward critically assessing putative evidence for information monitoring in non-human animals. However, less attention has been paid toward critically evaluating evidence for control processes in animals. We briefly review a critique of information-monitoring in animals. Next, we apply these concepts to a number of studies that focus on information seeking in animals. The main type of evidence for control processes in animals come from tube tipping experiments. Before having the opportunity to search for the bait in these experiments, the subject sometimes observes opaque tubes being baited but is sometimes prevented from seeing the baiting. The observations that the subjects look more if baiting was not seen and are more accurate if baiting was seen have been taken as evidence for metacognition in information-seeking experiments. We propose simple alternative hypotheses that are sufficient to explain putative evidence for information seeking in animals without positing metacognition. The alternative explanation focuses on two relatively simple principles： First, an animal has a default ＂look before you go＂ response which supersedes random searches in space. Second, spatially guided behavior follows a default rule of ＂go where something good is.＂ These principles can explain the results of tube tipping experiments without proposing metacognition [Current Zoology 57 （4）： 531-542, 2011].
