A double perturbation strategy is presented to solve the asymptotic solutions of a Johnson-Segalman （J-S） fluid through a slowly varying pipe. First, a small parameter of the slowly varying angle is taken as the sma...A double perturbation strategy is presented to solve the asymptotic solutions of a Johnson-Segalman （J-S） fluid through a slowly varying pipe. First, a small parameter of the slowly varying angle is taken as the small perturbation parameter, and then the second-order asymptotic solution of the flow of a Newtonian fluid through a slowly varying pipe is obtained in the first perturbation strategy. Second, the viscoelastic parameter is selected as the small perturbation parameter in the second perturbation strategy to solve the asymptotic solution of the flow of a J-S fluid through a slowly varying pipe. Finally, the parameter effects, including the axial distance, the slowly varying angle, and the Reynolds number, on the velocity distributions are analyzed. The results show that the increases in both the axial distance and the slowly varying angle make the axial velocity slow down. However, the radial velocity increases with the slowly varying angle, and decreases with the axial distance. There are two special positions in the distribution curves of the axial velocity and the radial velocity with different Reynolds numbers, and there are different trends on both sides of the special positions. The double perturbation strategy is applicable to such problems with the flow of a non-Newtonian fluid through a slowly varying pipe.展开更多
As one of the most popular English learning tools, the 7th edition of Oxford Advanced Learner's English-Chinese Dictionary aims to provide adequate information to satisfy learners' needs. In this article, this...As one of the most popular English learning tools, the 7th edition of Oxford Advanced Learner's English-Chinese Dictionary aims to provide adequate information to satisfy learners' needs. In this article, this latest edition is examined with re spect to two primary aspects: syntactic and semantic information based on Chan, A.C. and Y. Loong's evaluating criteria of learn er's dictionary. The focus falls on grammatical properties of nouns, verbs and adjectives, valency requirement, definitions, syn onyms and antonyms, collocations, etc. Conclusion suggests that the overall standard of this new dictionary is admirably high in terms of applicability and user-friendliness.展开更多
自Oxford Advanced Learner's Dictionary of Current English(以下简称《牛津》)和Zongman Dictionary of Contem porary English(以下简称《朗曼》)问世以来，它们在上世纪下半叶中一直风行全世界。这两本英语学习者词典的目的在...自Oxford Advanced Learner's Dictionary of Current English(以下简称《牛津》)和Zongman Dictionary of Contem porary English(以下简称《朗曼》)问世以来，它们在上世纪下半叶中一直风行全世界。这两本英语学习者词典的目的在于解决外国研习英语者所面临的特殊困难。展开更多
As a major resource and tool of language learning, learner’s dictionaries have provided sufficient information forL2 writing, which serves as a good guide of peer feedback. Hence, learner’s dictionaries are an indis...As a major resource and tool of language learning, learner’s dictionaries have provided sufficient information forL2 writing, which serves as a good guide of peer feedback. Hence, learner’s dictionaries are an indispensable partof scaffolding in the L2 writing feedback system. However, the effects of dictionary use in L2 writing have longbeen ignored either in L2 writing pedagogy or in learner lexicography. By applying the concept of “scaffolding” topeer feedback as the theoretical framework, this study first clarifies three distinct types of scaffolding informationpresented in current English learner’s dictionaries, and then makes an investigation into EFL learners’ perceptionand practical use of scaffolding information in their English writing. Results show that most EFL learners havepositive attitudes towards scaffolding information and its role in motivating effective feedback in English writing.But their practical use of such information is not satisfactory owing to their inadequate skills and knowledge ofdictionary use. This reflects a high demand of a dictionary use course in universities, which will help to raise EFLlearners’ dictionary use efficiency as well as improve English teachers’ lexicographical expertise in English writingpedagogy.展开更多
The metaphysical poetry,as a rather influential literary school,plays a momentous andpredominant part in eariy seventeenth century English literature.The marked quality ofmetaphysical poetry,as practiced by Donne and ...The metaphysical poetry,as a rather influential literary school,plays a momentous andpredominant part in eariy seventeenth century English literature.The marked quality ofmetaphysical poetry,as practiced by Donne and his successors,is their philosophical subtlety orintellectual rigor,while the quintessence of which consists in its peculiar blend of thought andpassion of realistic violence and meditative refinements.Doctor Johnson accused the展开更多
According to Cowie(2002), choosing which type of dictionary depends on"several factors, including the year of study, the level of linguistic proficiency of the users, and the nature of the study activity"(p....According to Cowie(2002), choosing which type of dictionary depends on"several factors, including the year of study, the level of linguistic proficiency of the users, and the nature of the study activity"(p. 195). After comparing the features of monolingual and bilingual learner's dictionaries, and examining the definitions and examples of three entry words(‘owe',‘deadlock'and‘pertinent') in six popular learner's dictionaries in China, we make a tentative conclusion that bilingualised dictionary is the better choice in vocabulary learning of Chinese college students as non-English majors. Some further investigations have to be conducted about the status quo of dictionary use among Chinese college students as non-English majors and their vocabulary learning strategies.展开更多
The diameter distribution of trees in a stand provides the basis for determining the stand’s ecological and economic value,its structure and stability and appropriate management practices.Scots pine(Pinus sylvestris ...The diameter distribution of trees in a stand provides the basis for determining the stand’s ecological and economic value,its structure and stability and appropriate management practices.Scots pine(Pinus sylvestris L.)is one of the most common and important conifers in Turkey,so a well-planned management schedule is critical.Diameter distribution models to accurately describe the stand structure help improve management strategies,but developing reliable models requires a deep understanding of the growth,output and constraints of the forests.The most important information derived by diameter distribution models is primary data on horizontal stand structure for each diameter class of trees:basal area and volume per unit area.These predictions are required to estimate the range of products and predicted volume and yield from a forest stand.Here,to construct an accurate,reliable diameter distribution model for natural Scots pine stands in the Türkmen Mountain region,we used Johnson’s SBdistribution to represent the empirical diameter distributions of the stands using ground-based measurements from 55 sample plots that included1219 trees in natural distribution zones of the forests.As an alternative,nonparametric approach,which does not require any predefined function,an artificial intelligence model was constructed based on support vector machine methodology.An error index was calculated to evaluate the results.Overall,both Johnson’s SB probability density function with a three-parameter recovery approach and the support vector regression methodology provided reliable estimates of the diameter distribution of these stands.展开更多
基金supported by the National Natural Science Foundation of China(Nos.11572203 and11332006)
文摘A double perturbation strategy is presented to solve the asymptotic solutions of a Johnson-Segalman （J-S） fluid through a slowly varying pipe. First, a small parameter of the slowly varying angle is taken as the small perturbation parameter, and then the second-order asymptotic solution of the flow of a Newtonian fluid through a slowly varying pipe is obtained in the first perturbation strategy. Second, the viscoelastic parameter is selected as the small perturbation parameter in the second perturbation strategy to solve the asymptotic solution of the flow of a J-S fluid through a slowly varying pipe. Finally, the parameter effects, including the axial distance, the slowly varying angle, and the Reynolds number, on the velocity distributions are analyzed. The results show that the increases in both the axial distance and the slowly varying angle make the axial velocity slow down. However, the radial velocity increases with the slowly varying angle, and decreases with the axial distance. There are two special positions in the distribution curves of the axial velocity and the radial velocity with different Reynolds numbers, and there are different trends on both sides of the special positions. The double perturbation strategy is applicable to such problems with the flow of a non-Newtonian fluid through a slowly varying pipe.
文摘As one of the most popular English learning tools, the 7th edition of Oxford Advanced Learner's English-Chinese Dictionary aims to provide adequate information to satisfy learners' needs. In this article, this latest edition is examined with re spect to two primary aspects: syntactic and semantic information based on Chan, A.C. and Y. Loong's evaluating criteria of learn er's dictionary. The focus falls on grammatical properties of nouns, verbs and adjectives, valency requirement, definitions, syn onyms and antonyms, collocations, etc. Conclusion suggests that the overall standard of this new dictionary is admirably high in terms of applicability and user-friendliness.
文摘自Oxford Advanced Learner's Dictionary of Current English(以下简称《牛津》)和Zongman Dictionary of Contem porary English(以下简称《朗曼》)问世以来，它们在上世纪下半叶中一直风行全世界。这两本英语学习者词典的目的在于解决外国研习英语者所面临的特殊困难。
文摘As a major resource and tool of language learning, learner’s dictionaries have provided sufficient information forL2 writing, which serves as a good guide of peer feedback. Hence, learner’s dictionaries are an indispensable partof scaffolding in the L2 writing feedback system. However, the effects of dictionary use in L2 writing have longbeen ignored either in L2 writing pedagogy or in learner lexicography. By applying the concept of “scaffolding” topeer feedback as the theoretical framework, this study first clarifies three distinct types of scaffolding informationpresented in current English learner’s dictionaries, and then makes an investigation into EFL learners’ perceptionand practical use of scaffolding information in their English writing. Results show that most EFL learners havepositive attitudes towards scaffolding information and its role in motivating effective feedback in English writing.But their practical use of such information is not satisfactory owing to their inadequate skills and knowledge ofdictionary use. This reflects a high demand of a dictionary use course in universities, which will help to raise EFLlearners’ dictionary use efficiency as well as improve English teachers’ lexicographical expertise in English writingpedagogy.
文摘The metaphysical poetry,as a rather influential literary school,plays a momentous andpredominant part in eariy seventeenth century English literature.The marked quality ofmetaphysical poetry,as practiced by Donne and his successors,is their philosophical subtlety orintellectual rigor,while the quintessence of which consists in its peculiar blend of thought andpassion of realistic violence and meditative refinements.Doctor Johnson accused the
文摘According to Cowie(2002), choosing which type of dictionary depends on"several factors, including the year of study, the level of linguistic proficiency of the users, and the nature of the study activity"(p. 195). After comparing the features of monolingual and bilingual learner's dictionaries, and examining the definitions and examples of three entry words(‘owe',‘deadlock'and‘pertinent') in six popular learner's dictionaries in China, we make a tentative conclusion that bilingualised dictionary is the better choice in vocabulary learning of Chinese college students as non-English majors. Some further investigations have to be conducted about the status quo of dictionary use among Chinese college students as non-English majors and their vocabulary learning strategies.
基金supported by Turkish General Directorate of Forestry。
文摘The diameter distribution of trees in a stand provides the basis for determining the stand’s ecological and economic value,its structure and stability and appropriate management practices.Scots pine(Pinus sylvestris L.)is one of the most common and important conifers in Turkey,so a well-planned management schedule is critical.Diameter distribution models to accurately describe the stand structure help improve management strategies,but developing reliable models requires a deep understanding of the growth,output and constraints of the forests.The most important information derived by diameter distribution models is primary data on horizontal stand structure for each diameter class of trees:basal area and volume per unit area.These predictions are required to estimate the range of products and predicted volume and yield from a forest stand.Here,to construct an accurate,reliable diameter distribution model for natural Scots pine stands in the Türkmen Mountain region,we used Johnson’s SBdistribution to represent the empirical diameter distributions of the stands using ground-based measurements from 55 sample plots that included1219 trees in natural distribution zones of the forests.As an alternative,nonparametric approach,which does not require any predefined function,an artificial intelligence model was constructed based on support vector machine methodology.An error index was calculated to evaluate the results.Overall,both Johnson’s SB probability density function with a three-parameter recovery approach and the support vector regression methodology provided reliable estimates of the diameter distribution of these stands.
