Rock residual strength,as an important input parameter,plays an indispensable role in proposing the reasonable and scientific scheme about stope design,underground tunnel excavation and stability evaluation of deep ch...Rock residual strength,as an important input parameter,plays an indispensable role in proposing the reasonable and scientific scheme about stope design,underground tunnel excavation and stability evaluation of deep chambers.Therefore,previous residual strength models of rocks established were reviewed.And corresponding related problems were stated.Subsequently,starting from the effects of bedding and whole life-cycle evolution process,series of triaxial mechanical tests of deep bedded sandstone with five bedding angles were conducted under different confining pressures.Then,six residual strength models considering the effects of bedding and whole life-cycle evolution process were established and evaluated.Finally,a cohesion loss model for determining residual strength of deep bedded sandstone was verified.The results showed that the effects of bedding and whole life-cycle evolution process had both significant influences on the evolution characteristic of residual strength of deep bedded sandstone.Additionally,residual strength parameters:residual cohesion and residual internal friction angle of deep bedded sandstone were not constant,which both significantly changed with increasing bedding angle.Besides,the cohesion loss model was the most suitable for determining and estimating the residual strength of bedded rocks,which could provide more accurate theoretical guidance for the stability control of deep chambers.展开更多
Dispersal is an important individual decision which may influence individual fitness as well as population viability.The social cohesion hypothesis posits more social individuals remain at home,which is supported by p...Dispersal is an important individual decision which may influence individual fitness as well as population viability.The social cohesion hypothesis posits more social individuals remain at home,which is supported by prior work across taxa.However,how the sociality and connectivity of the group an individual resides in—their group social structure—relates to dispersal decisions has not been explored.We extend the social cohesion hypothesis to predict individuals residing in more social groups would remain at home,and we quantified the affiliative and agonistic social network structure of female yellow-bellied marmots(Marmota flaviventer),a facultatively social ground-dwelling squirrel,where about half of all females disperse.Using mixed-effects models,we found no support for the hypothesis that affiliative group structure explained any variation in a marmot’s decision to disperse.We did find marmots in groups with less agonistic centralization(around one or few individuals)were less likely to disperse.The former finding may result from limited ability to perceive group structure whereas the latter may reflect individuals in less agonistically centralized groups are less likely to be reproductively suppressed.These results suggest individual dispersal decisions are more impacted by individual sociality and not that of their social group.Thus,the social cohesion hypothesis may not scale to the level of the group.Further work is required to determine whether dispersal decisions in obligately social species are influenced by group social structure.展开更多
As a major criterion for textuality and a prominent term in discourse analysis, discourse cohesion is used on the one hand, to identify the linguistic features that cause the sentences to ＂cohere＂, and on the other ...As a major criterion for textuality and a prominent term in discourse analysis, discourse cohesion is used on the one hand, to identify the linguistic features that cause the sentences to ＂cohere＂, and on the other hand, is to make the sentences in the discourse display some kind of mutual dependence. The paper has intensively analyzed the radio interview between Edward Heath and an interviewer from the perspective of discourse cohesion. After an in-depth analysis, the paper concludes that the interview is quite structurally cohesive by adopting several grammatical cohesive devices or ties, such as the verbal form, the time relator, the conjunction, the reference, the substitution, and the ellipsis, especially the reference and conjunction展开更多
This paper suggests that a single class rather than methods should be used as the slice scope to compute class cohesion. First, for a given attribute, the statements in all methods that last define the attribute are c...This paper suggests that a single class rather than methods should be used as the slice scope to compute class cohesion. First, for a given attribute, the statements in all methods that last define the attribute are computed. Then, the forward and backward data slices for this attribute are generated by using the class as the slice scope and are combined to compute the corresponding class data slice. Finally, the class cohesion is computed based on all class data slices for the attributes. Compared to traditional cohesion metrics that use methods as the slice scope, the proposed metrics that use a single class as slice scope take into account the possible interactions between the methods. The experimental results show that class cohesion can be more accurately measured when using the class as the slice scope.展开更多
Urban cohesion is a new development phenomenon of urbanization, requires further study in both practices and theories. In this study, the connotation, development premise and existing problems of urbanization have bee...Urban cohesion is a new development phenomenon of urbanization, requires further study in both practices and theories. In this study, the connotation, development premise and existing problems of urbanization have been primarily explored, to obtain useful ideas.展开更多
This article discusses one of the important cohesion means—lexis cohesion, and applies it to English reading. This cohesion contributes to the improvement of reading ability for its immediateness and accessibility. I...This article discusses one of the important cohesion means—lexis cohesion, and applies it to English reading. This cohesion contributes to the improvement of reading ability for its immediateness and accessibility. It aims at specifying the potentials of the theory in English reading learning by analysis and exemplification.展开更多
Discourse analysis is gaining its prominence in teaching reading. The paper presents an example of analyzing the system of reference and lexical cohesion of a news report. It demonstrates how to involve discourse anal...Discourse analysis is gaining its prominence in teaching reading. The paper presents an example of analyzing the system of reference and lexical cohesion of a news report. It demonstrates how to involve discourse analysis into the teaching of newspaper reading in order to make students get a clear framework of reference and lexical cohesion in a functional-grammar-conscious manner.展开更多
In the study of textlinguistics,cohesion is one important subject. According Halliday and Hasan,cohesion can be achieved through two ways. One is lexical cohesion and the other is grammatical cohesion. Reference is on...In the study of textlinguistics,cohesion is one important subject. According Halliday and Hasan,cohesion can be achieved through two ways. One is lexical cohesion and the other is grammatical cohesion. Reference is one of the most important devices in grammatical cohesion. It can be divided into personal reference,demonstrative reference,and comparative reference. Some of these references can be used as cataphora,some can be used as anaphora and some can be used as both. Analysis and explanation as well as examples are provided in this paper to facilitate the reader's understanding and use of reference.展开更多
This thesis aims to analyze the means of cohesion in"of Studies"by Francis Bacon.According to the systemic-functional linguistics,the paper is intended to explore cohesion means applied in Of Studies by Fran...This thesis aims to analyze the means of cohesion in"of Studies"by Francis Bacon.According to the systemic-functional linguistics,the paper is intended to explore cohesion means applied in Of Studies by Francis Bacon.It gives an account of the functions in grammatical cohesion in the several fields,they are reference,substitution,ellipsis,and conjunction respectively.Finally,it is expected that these analyses can help readers gain a better and deeper comprehension of the structure and content of the text.展开更多
Cohesion tends to be denser and more noticeable in written discourse than in spoken discourse. A text will become problematic or is not easy to make sense to readers if any cohesion is troubled. The present paper is g...Cohesion tends to be denser and more noticeable in written discourse than in spoken discourse. A text will become problematic or is not easy to make sense to readers if any cohesion is troubled. The present paper is going to investigate cohesion in Chinese advanced learners' expository writing by comparing and analyzing the cohesive ties in two student writers' essays.展开更多
Black locust（Robinia pseudoacacia L.） and Chinese pine（Pinus tabulaeformis Carr.） are two woody plants that are widely planted on the Loess Plateau for controlling soil erosion and land desertification. In this st...Black locust（Robinia pseudoacacia L.） and Chinese pine（Pinus tabulaeformis Carr.） are two woody plants that are widely planted on the Loess Plateau for controlling soil erosion and land desertification. In this study, we conducted an excavation experiment in 2008 to investigate the overall vertical root distribution characteristics of black locust and Chinese pine. We also performed triaxial compression tests to evaluate the root cohesion（additional soil cohesion increased by roots） of black locust. Two types of root distribution, namely, vertical root（VR） and horizontal root（HR）, were used as samples and tested under four soil water content（SWC） conditions（12.7%, 15.0%, 18.0% and 20.0%, respectively）. Results showed that the root lengths of the two species were mainly concentrated in the root diameter of 5–20 mm. A comparison of root distribution between the two species indicated that the root length of black locust was significantly greater than that of Chinese pine in nearly all root diameters, although the black locust used in the comparison was 10 years younger than the Chinese pine. Root biomass was also significantly greater in black locust than in Chinese pine, particularly in the root diameters of 3–5 and 5–10 mm. These two species were both found to be deep-rooted. The triaxial compression tests showed that root cohesion was greater in the VR samples than in the HR samples. SWC was negatively related to both soil shear strength and root cohesion. These results could provide useful information on the architectural characteristics of woody root system and expand the knowledge on shallow slope stabilization and soil erosion control by plant roots on the Loess Plateau.展开更多
The limit equilibrium method （LEM） is widely used for sliding stability evaluation of concrete gravitydams. Failure is then commonly assumed to occur along the entire sliding surface simultaneously.However, the brit...The limit equilibrium method （LEM） is widely used for sliding stability evaluation of concrete gravitydams. Failure is then commonly assumed to occur along the entire sliding surface simultaneously.However, the brittle behaviour of bonded concrete-rock contacts, in combination with the varying stressover the interface, implies that the failure of bonded dam-foundation interfaces occurs progressively. Inaddition, the spatial variation in cohesion may introduce weak spots where failure can be initiated.Nonetheless, the combined effect of brittle failure and spatial variation in cohesion on the overall shearstrength of the interface has not been studied previously. In this paper, numerical analyses are used toinvestigate the effect of brittle failure in combination with spatial variation in cohesion that is taken intoaccount by random fields with different correlation lengths. The study concludes that a possible existenceof weak spots along the interface has to be considered since it significantly reduces the overallshear strength of the interface, and implications for doing so are discussed.展开更多
This paper presents two different algorithms that derive the cohesion structure in the form of lexical chains from two kinds of language resources HowNet and TongYiCiCiLin. The re-search that connects the cohesion str...This paper presents two different algorithms that derive the cohesion structure in the form of lexical chains from two kinds of language resources HowNet and TongYiCiCiLin. The re-search that connects the cohesion structure of a text to the derivation of its summary is displayed. A novel model of automatic text summarization is devised,based on the data provided by lexical chains from original texts. Moreover,the construction rules of lexical chains are modified accord-ing to characteristics of the knowledge database in order to be more suitable for Chinese summa-rization. Evaluation results show that high quality indicative summaries are produced from Chi-nese texts.展开更多
Effects of Cr, Mo, and Nb on the ferritic stainless steel ]2（210） grain boundary and intragranularity are investigated using the first-principles principle. Different positions of solute atoms are considered. Struct...Effects of Cr, Mo, and Nb on the ferritic stainless steel ]2（210） grain boundary and intragranularity are investigated using the first-principles principle. Different positions of solute atoms are considered. Structural stability is lowered by Cr doping and enhanced by Mo and Nb doping. A ranking on the effect of solute atoms enhancing the cohesive strength of the grain boundary, from the strongest to the weakest is Cr, Mo, and Nb. Cr clearly prefers to locate in the intragranular region of Fe rather than in the grain boundary, while Mo and Nb tend to segregate to the grain boundary. Solute Mo and Nb atoms possess a strong driving force for segregation to the grain boundary from the intragranular region, which increases the grain boundary embrittlement. For Mo- and Nb-doped systems, a remarkable quantity of electrons accumulate in the region close to Mo （Nb）. Therefore, the bond strength may increase. With Cr, Mo, and Nb additions, an anti-parallel island is formed around the center of the grain boundary.展开更多
It is know from literature that small additions(<1 wt%)of Ca,Al and Zn significantly improve the intrinsic ductility of Mg.The exact role of each element,both qualitatively and quantitatively,and their combined eff...It is know from literature that small additions(<1 wt%)of Ca,Al and Zn significantly improve the intrinsic ductility of Mg.The exact role of each element,both qualitatively and quantitatively,and their combined effects,however,are poorly understood.Here we achieved a much clearer view on the quantitative role of each element with respect to ductility improvement and on the collaborative effect,particularly of Ca and Zn in Mg.Some of our findings and conclusions are in disagreement with data and interpretation found in literature.Four different alloys,namely,Mg-0.1 Ca,Mg-0.1 Ca-1 Al,Mg-0.05 Ca-1 Al,Mg-0.1 Ca-2 Al-1 Zn(all are in wt%)were selected for this investigation.All alloys were treated such that approx.similar grain sizes and textures were obtained.This largely excludes the effect of extrinsic factors on ductility.EBSD-guided slip trace analyses reveal that the addition of Ca eases activation of prismatic and pyramidal II slip systems.Using in-situ deformation experiments in SEM and atom probe tomography observations of grain boundaries direct evidence is given for the individual and synergetic effects of Ca and Zn on grain boundary cohesion as an important contribution to improve the ductility of these alloys.We conclude that Ca reduces the slip anisotropy and ameliorates ductility,however,the weak grain boundary cohesion in the Mg-0.1 wt%Ca alloy limits the material’s tensile ductility.The addition of Zn alters the Ca segregation at the grain boundaries and helps to retain their cohesive strength,an effect which thus enables higher ductility and strength.The further addition of Al primarily improves the strength.The results show that the balanced influence of reduced slip anisotropy on the one hand and increased grain boundary cohesion on the other hand allow to design a high strength high ductility rare-earth free Mg alloy.展开更多
Severe faults have caused many earthquakes around the world throughout history.More recently,earthquakes have occurred in Taiwan,China(Chi-Chi fault),and elsewhere,causing loss of lives and destroying many buildings a...Severe faults have caused many earthquakes around the world throughout history.More recently,earthquakes have occurred in Taiwan,China(Chi-Chi fault),and elsewhere,causing loss of lives and destroying many buildings and structures.These tectonic movements have gained attention from engineers,and in the past 15 years,the focus has been on faulting mechanisms.In this study,a physical model(1 g)was fabricated and used to evaluate the impact of a reverse fault in a field with a tunnel.In the 1 g model,researchers installed additional gauges on the tunnel,so that all the displacements could be adjusted,and all the responses could be monitored during faulting.An experimental study of various soil properties(cohesion and friction angles)in reverse faults on the tunnel lining were carried out and are described herein.A comparison of results for different levels of soil cohesion revealed that it can dramatically reduce the displacement by as much as 40%,and that friction angles of 27ºcan record approximately 60%more displacements than at 37º.Furthermore,a comparison of fault angles of 30ºand 60ºindicates that the displacements can be different by more than 43%in cohesionless soil and about 64%for a friction angle of 27º.展开更多
BACKGROUND Depression is the most common mental illness in postpartum mothers,and the etiology of postpartum depression remains poorly understood.Over the past several decades,studies have reported that postpartum dep...BACKGROUND Depression is the most common mental illness in postpartum mothers,and the etiology of postpartum depression remains poorly understood.Over the past several decades,studies have reported that postpartum depression is caused by multiple factors,such as genetic,psychological,pregnancy,and environmental factors,with the family environment being an important environmental factor.The theory of family cohesion and adaptability put forward by Olson is a classic model that describes the level of family function.However,to date,this model has not been examined regarding its applicability to patients with postpartum depression.AIM To investigate the relationship between family cohesion and adaptability and the risk of postpartum depressive symptoms.METHODS We retrospectively analyzed 1446 patients admitted to the postpartum healthcare clinic of the Affiliated Foshan Maternity and Child Healthcare Hospital from April 2021 to December 2021.Patients were grouped according to whether postpartum depression symptoms were reported(symptoms,n=454;no symptoms,n=992).All patients completed the Edinburgh Postpartum Depression Scale and the Chinese version of the Family Cohesion and Adaptability Assessment Scale II.Baseline and clinical data were compared between groups.Univariate regression analysis was used to investigate the association between different types of family cohesion and postpartum depressive symptoms and the association between different family adaptability types and postpartum depressive symptoms.RESULTS After adjusting for age,education,occupation,gravidity,parity,and mode of delivery,disengaged[adjusted odds ratio(AOR)=3.36,95%CI:1.91-5.91],and separated(AOR=1.97,95%CI:1.34-2.90)family cohesion types showed a higher risk of postpartum depression than the connection type,whereas the enmeshed type(AOR=0.38,95%CI:0.28-0.51)protected against postpartum depressive symptoms.Rigid(AOR=4.41,95%CI:3.02-6.43)and structured families(AOR=1.88,95%CI:1.34-2.63)had a higher risk of postpartum depressive symptoms than flexible families,whereas chaotic families(AOR=0.35,95%CI:0.24-0.51)protected against postpartum depressive symptoms.CONCLUSION Family cohesion and adaptability are influencing factors for postpartum depressive symptoms,with higher family cohesion and adaptability being associated with a lower risk of postpartum depressive symptoms.展开更多
The interaction between the classes or within the classes shows the complexity of the design. For one smaller problem, there may be more than one software design but who will be the best;depends on the complexity leve...The interaction between the classes or within the classes shows the complexity of the design. For one smaller problem, there may be more than one software design but who will be the best;depends on the complexity level of software design. Therefore, coupling and cohesion which shows the interlinking of classes and strength of classes;control the complexity of the design. The best software object oriented design is based upon the low coupling and high cohesion level. In the present work, a real case study of Life Insurance policy for handicapped person is demonstrated through the UML Class Diagram;coupling and cohesion levels are measured and results are demonstrated in the form of tables.展开更多
Cohesion and coherence are two of the most important components in discourse analysis. This thesis investigales some cohesive devices and coherent means. At zhe same time, it gives an account of how a text is identifi...Cohesion and coherence are two of the most important components in discourse analysis. This thesis investigales some cohesive devices and coherent means. At zhe same time, it gives an account of how a text is identified as a text. It also discusses the relationship between cohesion and coherence.展开更多
基金Projects(2024YFC3013801,2022YFC3004602)supported by the National Key R&D Program of ChinaProjects(U23B2093,52034009)supported by the National Natural Science Foundation of China。
文摘Rock residual strength,as an important input parameter,plays an indispensable role in proposing the reasonable and scientific scheme about stope design,underground tunnel excavation and stability evaluation of deep chambers.Therefore,previous residual strength models of rocks established were reviewed.And corresponding related problems were stated.Subsequently,starting from the effects of bedding and whole life-cycle evolution process,series of triaxial mechanical tests of deep bedded sandstone with five bedding angles were conducted under different confining pressures.Then,six residual strength models considering the effects of bedding and whole life-cycle evolution process were established and evaluated.Finally,a cohesion loss model for determining residual strength of deep bedded sandstone was verified.The results showed that the effects of bedding and whole life-cycle evolution process had both significant influences on the evolution characteristic of residual strength of deep bedded sandstone.Additionally,residual strength parameters:residual cohesion and residual internal friction angle of deep bedded sandstone were not constant,which both significantly changed with increasing bedding angle.Besides,the cohesion loss model was the most suitable for determining and estimating the residual strength of bedded rocks,which could provide more accurate theoretical guidance for the stability control of deep chambers.
基金supported by the Hamilton College Jeffery Fund Science Internship and the Rocky Mountain Biological Laboratorysupported by the University of California Los Angeles,American Society of Mammalogists,the Animal Behavior Society,and Rocky Mountain Biological Laboratory+1 种基金supported by the National Geographic Society,the University of California Los Angeles(Faculty Senate and Division of Life Sciences),an RMBL research fellowshipU.S.National Science Foundation(NSF IDBR-0754247 and DEB-1119660 and 1557130 to D.T.B.,as well as DBI 0242960,07211346,1226713,and 1755522 to RMBL).
文摘Dispersal is an important individual decision which may influence individual fitness as well as population viability.The social cohesion hypothesis posits more social individuals remain at home,which is supported by prior work across taxa.However,how the sociality and connectivity of the group an individual resides in—their group social structure—relates to dispersal decisions has not been explored.We extend the social cohesion hypothesis to predict individuals residing in more social groups would remain at home,and we quantified the affiliative and agonistic social network structure of female yellow-bellied marmots(Marmota flaviventer),a facultatively social ground-dwelling squirrel,where about half of all females disperse.Using mixed-effects models,we found no support for the hypothesis that affiliative group structure explained any variation in a marmot’s decision to disperse.We did find marmots in groups with less agonistic centralization(around one or few individuals)were less likely to disperse.The former finding may result from limited ability to perceive group structure whereas the latter may reflect individuals in less agonistically centralized groups are less likely to be reproductively suppressed.These results suggest individual dispersal decisions are more impacted by individual sociality and not that of their social group.Thus,the social cohesion hypothesis may not scale to the level of the group.Further work is required to determine whether dispersal decisions in obligately social species are influenced by group social structure.
文摘As a major criterion for textuality and a prominent term in discourse analysis, discourse cohesion is used on the one hand, to identify the linguistic features that cause the sentences to ＂cohere＂, and on the other hand, is to make the sentences in the discourse display some kind of mutual dependence. The paper has intensively analyzed the radio interview between Edward Heath and an interviewer from the perspective of discourse cohesion. After an in-depth analysis, the paper concludes that the interview is quite structurally cohesive by adopting several grammatical cohesive devices or ties, such as the verbal form, the time relator, the conjunction, the reference, the substitution, and the ellipsis, especially the reference and conjunction
基金The National Natural Science Foundation of China(No.60425206,60633010)the High Technology Research and Development Program of Jiangsu Province(No.BG2005032)
文摘This paper suggests that a single class rather than methods should be used as the slice scope to compute class cohesion. First, for a given attribute, the statements in all methods that last define the attribute are computed. Then, the forward and backward data slices for this attribute are generated by using the class as the slice scope and are combined to compute the corresponding class data slice. Finally, the class cohesion is computed based on all class data slices for the attributes. Compared to traditional cohesion metrics that use methods as the slice scope, the proposed metrics that use a single class as slice scope take into account the possible interactions between the methods. The experimental results show that class cohesion can be more accurately measured when using the class as the slice scope.
基金Supported by Key Knowledge Innovation Project of Chinese Academy of Sciences (KZCX2-YW-342,KZCX2-YW-321)Key Project of National Natural Science Foundation (40635030)~~
文摘Urban cohesion is a new development phenomenon of urbanization, requires further study in both practices and theories. In this study, the connotation, development premise and existing problems of urbanization have been primarily explored, to obtain useful ideas.
文摘This article discusses one of the important cohesion means—lexis cohesion, and applies it to English reading. This cohesion contributes to the improvement of reading ability for its immediateness and accessibility. It aims at specifying the potentials of the theory in English reading learning by analysis and exemplification.
文摘Discourse analysis is gaining its prominence in teaching reading. The paper presents an example of analyzing the system of reference and lexical cohesion of a news report. It demonstrates how to involve discourse analysis into the teaching of newspaper reading in order to make students get a clear framework of reference and lexical cohesion in a functional-grammar-conscious manner.
文摘In the study of textlinguistics,cohesion is one important subject. According Halliday and Hasan,cohesion can be achieved through two ways. One is lexical cohesion and the other is grammatical cohesion. Reference is one of the most important devices in grammatical cohesion. It can be divided into personal reference,demonstrative reference,and comparative reference. Some of these references can be used as cataphora,some can be used as anaphora and some can be used as both. Analysis and explanation as well as examples are provided in this paper to facilitate the reader's understanding and use of reference.
文摘This thesis aims to analyze the means of cohesion in"of Studies"by Francis Bacon.According to the systemic-functional linguistics,the paper is intended to explore cohesion means applied in Of Studies by Francis Bacon.It gives an account of the functions in grammatical cohesion in the several fields,they are reference,substitution,ellipsis,and conjunction respectively.Finally,it is expected that these analyses can help readers gain a better and deeper comprehension of the structure and content of the text.
文摘Cohesion tends to be denser and more noticeable in written discourse than in spoken discourse. A text will become problematic or is not easy to make sense to readers if any cohesion is troubled. The present paper is going to investigate cohesion in Chinese advanced learners' expository writing by comparing and analyzing the cohesive ties in two student writers' essays.
基金funded by the National Natural Science Foundation of China (30872067)the Youth Foundation of Taiyuan University of Technology (2012L017, 2013T037)
文摘Black locust（Robinia pseudoacacia L.） and Chinese pine（Pinus tabulaeformis Carr.） are two woody plants that are widely planted on the Loess Plateau for controlling soil erosion and land desertification. In this study, we conducted an excavation experiment in 2008 to investigate the overall vertical root distribution characteristics of black locust and Chinese pine. We also performed triaxial compression tests to evaluate the root cohesion（additional soil cohesion increased by roots） of black locust. Two types of root distribution, namely, vertical root（VR） and horizontal root（HR）, were used as samples and tested under four soil water content（SWC） conditions（12.7%, 15.0%, 18.0% and 20.0%, respectively）. Results showed that the root lengths of the two species were mainly concentrated in the root diameter of 5–20 mm. A comparison of root distribution between the two species indicated that the root length of black locust was significantly greater than that of Chinese pine in nearly all root diameters, although the black locust used in the comparison was 10 years younger than the Chinese pine. Root biomass was also significantly greater in black locust than in Chinese pine, particularly in the root diameters of 3–5 and 5–10 mm. These two species were both found to be deep-rooted. The triaxial compression tests showed that root cohesion was greater in the VR samples than in the HR samples. SWC was negatively related to both soil shear strength and root cohesion. These results could provide useful information on the architectural characteristics of woody root system and expand the knowledge on shallow slope stabilization and soil erosion control by plant roots on the Loess Plateau.
文摘The limit equilibrium method （LEM） is widely used for sliding stability evaluation of concrete gravitydams. Failure is then commonly assumed to occur along the entire sliding surface simultaneously.However, the brittle behaviour of bonded concrete-rock contacts, in combination with the varying stressover the interface, implies that the failure of bonded dam-foundation interfaces occurs progressively. Inaddition, the spatial variation in cohesion may introduce weak spots where failure can be initiated.Nonetheless, the combined effect of brittle failure and spatial variation in cohesion on the overall shearstrength of the interface has not been studied previously. In this paper, numerical analyses are used toinvestigate the effect of brittle failure in combination with spatial variation in cohesion that is taken intoaccount by random fields with different correlation lengths. The study concludes that a possible existenceof weak spots along the interface has to be considered since it significantly reduces the overallshear strength of the interface, and implications for doing so are discussed.
基金the Key Project of National Natural Sci-ence Foundation of China (No.60435020)the High Technology Research and Development Programme of China (No.2002AA117010-09).
文摘This paper presents two different algorithms that derive the cohesion structure in the form of lexical chains from two kinds of language resources HowNet and TongYiCiCiLin. The re-search that connects the cohesion structure of a text to the derivation of its summary is displayed. A novel model of automatic text summarization is devised,based on the data provided by lexical chains from original texts. Moreover,the construction rules of lexical chains are modified accord-ing to characteristics of the knowledge database in order to be more suitable for Chinese summa-rization. Evaluation results show that high quality indicative summaries are produced from Chi-nese texts.
基金Project supported by the National Natural Science Foundation of China(Grant No.51371123)the Specialized Research Foundation of the Doctoral Program for Institution of Higher Education of China(Grant No.2013140211003)+1 种基金the Science and Technology Research Project of Municipal Education Commission of Chongqin,China(Grant Nos.KJ131308 and KJ131315)the Natural Science Foundation of Science and Technology Commission of Chongqin,China(Grant No.cstc2012jjA90017)
文摘Effects of Cr, Mo, and Nb on the ferritic stainless steel ]2（210） grain boundary and intragranularity are investigated using the first-principles principle. Different positions of solute atoms are considered. Structural stability is lowered by Cr doping and enhanced by Mo and Nb doping. A ranking on the effect of solute atoms enhancing the cohesive strength of the grain boundary, from the strongest to the weakest is Cr, Mo, and Nb. Cr clearly prefers to locate in the intragranular region of Fe rather than in the grain boundary, while Mo and Nb tend to segregate to the grain boundary. Solute Mo and Nb atoms possess a strong driving force for segregation to the grain boundary from the intragranular region, which increases the grain boundary embrittlement. For Mo- and Nb-doped systems, a remarkable quantity of electrons accumulate in the region close to Mo （Nb）. Therefore, the bond strength may increase. With Cr, Mo, and Nb additions, an anti-parallel island is formed around the center of the grain boundary.
基金the financial support by the international doctoral school IMPRS,Surmat。
文摘It is know from literature that small additions(<1 wt%)of Ca,Al and Zn significantly improve the intrinsic ductility of Mg.The exact role of each element,both qualitatively and quantitatively,and their combined effects,however,are poorly understood.Here we achieved a much clearer view on the quantitative role of each element with respect to ductility improvement and on the collaborative effect,particularly of Ca and Zn in Mg.Some of our findings and conclusions are in disagreement with data and interpretation found in literature.Four different alloys,namely,Mg-0.1 Ca,Mg-0.1 Ca-1 Al,Mg-0.05 Ca-1 Al,Mg-0.1 Ca-2 Al-1 Zn(all are in wt%)were selected for this investigation.All alloys were treated such that approx.similar grain sizes and textures were obtained.This largely excludes the effect of extrinsic factors on ductility.EBSD-guided slip trace analyses reveal that the addition of Ca eases activation of prismatic and pyramidal II slip systems.Using in-situ deformation experiments in SEM and atom probe tomography observations of grain boundaries direct evidence is given for the individual and synergetic effects of Ca and Zn on grain boundary cohesion as an important contribution to improve the ductility of these alloys.We conclude that Ca reduces the slip anisotropy and ameliorates ductility,however,the weak grain boundary cohesion in the Mg-0.1 wt%Ca alloy limits the material’s tensile ductility.The addition of Zn alters the Ca segregation at the grain boundaries and helps to retain their cohesive strength,an effect which thus enables higher ductility and strength.The further addition of Al primarily improves the strength.The results show that the balanced influence of reduced slip anisotropy on the one hand and increased grain boundary cohesion on the other hand allow to design a high strength high ductility rare-earth free Mg alloy.
文摘Severe faults have caused many earthquakes around the world throughout history.More recently,earthquakes have occurred in Taiwan,China(Chi-Chi fault),and elsewhere,causing loss of lives and destroying many buildings and structures.These tectonic movements have gained attention from engineers,and in the past 15 years,the focus has been on faulting mechanisms.In this study,a physical model(1 g)was fabricated and used to evaluate the impact of a reverse fault in a field with a tunnel.In the 1 g model,researchers installed additional gauges on the tunnel,so that all the displacements could be adjusted,and all the responses could be monitored during faulting.An experimental study of various soil properties(cohesion and friction angles)in reverse faults on the tunnel lining were carried out and are described herein.A comparison of results for different levels of soil cohesion revealed that it can dramatically reduce the displacement by as much as 40%,and that friction angles of 27ºcan record approximately 60%more displacements than at 37º.Furthermore,a comparison of fault angles of 30ºand 60ºindicates that the displacements can be different by more than 43%in cohesionless soil and about 64%for a friction angle of 27º.
基金Supported by Foundation of Bureau of Science and Technology of Foshan City,No.2020001005566。
文摘BACKGROUND Depression is the most common mental illness in postpartum mothers,and the etiology of postpartum depression remains poorly understood.Over the past several decades,studies have reported that postpartum depression is caused by multiple factors,such as genetic,psychological,pregnancy,and environmental factors,with the family environment being an important environmental factor.The theory of family cohesion and adaptability put forward by Olson is a classic model that describes the level of family function.However,to date,this model has not been examined regarding its applicability to patients with postpartum depression.AIM To investigate the relationship between family cohesion and adaptability and the risk of postpartum depressive symptoms.METHODS We retrospectively analyzed 1446 patients admitted to the postpartum healthcare clinic of the Affiliated Foshan Maternity and Child Healthcare Hospital from April 2021 to December 2021.Patients were grouped according to whether postpartum depression symptoms were reported(symptoms,n=454;no symptoms,n=992).All patients completed the Edinburgh Postpartum Depression Scale and the Chinese version of the Family Cohesion and Adaptability Assessment Scale II.Baseline and clinical data were compared between groups.Univariate regression analysis was used to investigate the association between different types of family cohesion and postpartum depressive symptoms and the association between different family adaptability types and postpartum depressive symptoms.RESULTS After adjusting for age,education,occupation,gravidity,parity,and mode of delivery,disengaged[adjusted odds ratio(AOR)=3.36,95%CI:1.91-5.91],and separated(AOR=1.97,95%CI:1.34-2.90)family cohesion types showed a higher risk of postpartum depression than the connection type,whereas the enmeshed type(AOR=0.38,95%CI:0.28-0.51)protected against postpartum depressive symptoms.Rigid(AOR=4.41,95%CI:3.02-6.43)and structured families(AOR=1.88,95%CI:1.34-2.63)had a higher risk of postpartum depressive symptoms than flexible families,whereas chaotic families(AOR=0.35,95%CI:0.24-0.51)protected against postpartum depressive symptoms.CONCLUSION Family cohesion and adaptability are influencing factors for postpartum depressive symptoms,with higher family cohesion and adaptability being associated with a lower risk of postpartum depressive symptoms.
文摘The interaction between the classes or within the classes shows the complexity of the design. For one smaller problem, there may be more than one software design but who will be the best;depends on the complexity level of software design. Therefore, coupling and cohesion which shows the interlinking of classes and strength of classes;control the complexity of the design. The best software object oriented design is based upon the low coupling and high cohesion level. In the present work, a real case study of Life Insurance policy for handicapped person is demonstrated through the UML Class Diagram;coupling and cohesion levels are measured and results are demonstrated in the form of tables.
文摘Cohesion and coherence are two of the most important components in discourse analysis. This thesis investigales some cohesive devices and coherent means. At zhe same time, it gives an account of how a text is identified as a text. It also discusses the relationship between cohesion and coherence.
