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
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
BACKGROUND Colorectal signet-ring cell carcinoma(CSRCC)is a rare clinical entity which accounts for approximately 1%of all colorectal cancers.Although multiple studies concerning this specific topic have been publishe...BACKGROUND Colorectal signet-ring cell carcinoma(CSRCC)is a rare clinical entity which accounts for approximately 1%of all colorectal cancers.Although multiple studies concerning this specific topic have been published in the past decades,the pathogenesis,associated risk factors,and potential implications on treatment are still poorly understood.Besides the low incidence,historically confusing histological criteria have resulted in confusing data.Nevertheless,the rising incidence of CSRCC along with relatively young age at presentation and associated dismal prognosis,highlight the actual interest to synthesize the known literature regarding CSRCC.AIM To provide an updated overview of risk factors,prognosis,and management of CSRCC.METHODS A literature search in the MEDLINE/PubMed database was conducted with the following search terms used:‘Signet ring cell carcinoma’and‘colorectal’.Studies in English language,published after January 1980,were included.Studies included in the qualitative synthesis were evaluated for content concerning epidemiology,risk factors,and clinical,diagnostic,histological,and molecular features,as well as metastatic pattern and therapeutic management.If possible,presented data was extracted in order to present a more detailed overview of the literature.RESULTS In total,67 articles were included for qualitative analysis,of which 54 were eligible for detailed data extraction.CSRCC has a reported incidence between 0.1%-2.4%and frequently presents with advanced disease stage at the time of diagnosis.CSRCC is associated with an impaired overall survival(5-year OS:0%-46%)and a worse stagecorrected outcome compared to mucinous and not otherwise specified adenocarcinoma.The systematic use of exploratory laparoscopy to determine the presence of peritoneal metastases has been advised.Surgery is the mainstay of treatment,although the rates of curative resection in CSRCC(21%-82%)are lower compared to those in other histological types.In case of peritoneal metastasis,cytoreductive surgery with hyperthermic intraperitoneal chemotherapy should only be proposed in selected patients.CONCLUSION CSRCC is a rare clinical entity most often characterized by young age and advanced disease at presentation.As such,diagnostic modalities and therapeutic approach should be tailored accordingly.展开更多
Under the guidance of Systemic-Functional Grammar(SFG),cohesion is applied to analyze the selected context.Cohesion plays a great role in organizing a whole context and it can be further divided into grammatical cohes...Under the guidance of Systemic-Functional Grammar(SFG),cohesion is applied to analyze the selected context.Cohesion plays a great role in organizing a whole context and it can be further divided into grammatical cohesion and lexical cohesion.Main ideas of cohesion are illustrated and made it for application,which employs British children's literature-The Water Babies as the object.The research method adopted here is mainly quantitative.Through analyzing selected sections,it is obvious that cohesion helps readers understand the contexts better.Besides,the use of cohesion makes the context more precise and compact.For context,the role of cohesion is irreplaceable.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
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
Grain boundary engineering plays a significant role in the improvement of strength and plasticity of alloys. However, in refractory high-entropy alloys, the susceptibility of grain boundaries to oxygen presents a bott...Grain boundary engineering plays a significant role in the improvement of strength and plasticity of alloys. However, in refractory high-entropy alloys, the susceptibility of grain boundaries to oxygen presents a bottleneck in achieving high mechanical performance. Creating a large number of clean grain boundaries in refractory high-entropy alloys is a challenge. In this study, an ultrafine-grained (UFG) NbMoTaW alloy with high grain-boundary cohesion was prepared by powder metallurgy, taking advantages of rapid hot-pressing sintering and full-process inert atmosphere protection from powder synthesis to sintering. By oxygen control and an increase in the proportion of grain boundaries, the segregation of oxygen and formation of oxides at grain boundaries were strongly mitigated, thus the intrinsic high cohesion of the interfaces was preserved. Compared to the coarse-grained alloys prepared by arc-melting and those sintered by traditional powder metallurgy methods, the UFG NbMoTaW alloy demonstrated simultaneously increased strength and plasticity at ambient temperature. The highly cohesive grain boundaries not only reduce brittle fractures effectively but also promote intragranular deformation. Consequently, the UFG NbMoTaW alloy achieved a high yield strength even at elevated temperatures, with a remarkable performance of 1117 MPa at 1200 ℃. This work provides a feasible solution for producing refractory high-entropy alloys with low impurity content, refined microstructure, and excellent mechanical performance.展开更多
A coupled thermal-hydro-mechanical cohesive phase-field model for hydraulic fracturing in deep coal seams is presented.Heat exchange between the cold fluid and the hot rock is considered,and the thermal contribution t...A coupled thermal-hydro-mechanical cohesive phase-field model for hydraulic fracturing in deep coal seams is presented.Heat exchange between the cold fluid and the hot rock is considered,and the thermal contribution terms between the cold fluid and the hot rock are derived.Heat transfer obeys Fourier's law,and porosity is used to relate the thermodynamic parameters of the fracture and matrix domains.The net pressure difference between the fracture and the matrix is neglected,and thus the fluid flow is modeled by the unified fluid-governing equations.The evolution equations of porosity and Biot's coefficient during hydraulic fracturing are derived from their definitions.The effect of coal cleats is considered and modeled by Voronoi polygons,and this approach is shown to have high accuracy.The accuracy of the proposed model is verified by two sets of fracturing experiments in multilayer coal seams.Subsequently,the differences in fracture morphology,fluid pressure response,and fluid pressure distribution between direct fracturing of coal seams and indirect fracturing of shale interlayers are explored,and the effects of the cluster number and cluster spacing on fracture morphology for multi-cluster fracturing are also examined.The numerical results show that the proposed model is expected to be a powerful tool for the fracturing design and optimization of deep coalbed methane.展开更多
This study investigates the bond performance at the interfacial region shared by Ultra-High Performance Concrete(UHPC)and steel tubes through push-out tests.This study examines how changes in steel fiber volumetric ra...This study investigates the bond performance at the interfacial region shared by Ultra-High Performance Concrete(UHPC)and steel tubes through push-out tests.This study examines how changes in steel fiber volumetric ratio and thickness of steel tube influence the bond strength characteristics.The results show that as the enhancement of the steel tube wall thickness,the ultimate bond strength at the interface improves significantly,whereas the initial bond strength exhibits only slight variations.The influence of steel fiber volumetric ratio presents a nonlinear trend,with initial bond strength decreasing at low fiber content and increasing significantly as fiber content rises.Additionally,finite element(FE)simulations were applied to replicate the experimental conditions,and the outcomes showed strong correlation with the experimental data,confirming the exactitude of the FE model in predicting the bond behavior at the UHPC-Steel interface.These findings provide valuable insights for optimizing the design of UHPC-Filled steel tubes in high-performance structure.展开更多
1.A.Mertha,“‘Stressing Out’:Cadre Calibration and Affective Proximity to the CCP in Reform-Era China”,The China Quarterly,Vol.229,2017,pp.64-85.2.B.L.McCormick,“Book Review of‘The Chinese Communist Party's C...1.A.Mertha,“‘Stressing Out’:Cadre Calibration and Affective Proximity to the CCP in Reform-Era China”,The China Quarterly,Vol.229,2017,pp.64-85.2.B.L.McCormick,“Book Review of‘The Chinese Communist Party's Capacity to Rule:Ideology,Legitimacy and Party Cohesion’”,The China Journal,Vol.77,2017,pp.161-163.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
This paper investigates the mechanisms of rock failure related to axial splitting and shear failure due to hoop stresses in cylindrical specimens.The hoop stresses are caused by normal viscous stress.The rheological d...This paper investigates the mechanisms of rock failure related to axial splitting and shear failure due to hoop stresses in cylindrical specimens.The hoop stresses are caused by normal viscous stress.The rheological dynamics theory(RDT)is used,with the mechanical parameters being determined by P-and S-wave velocities.The angle of internal friction is determined by the ratio of Young's modulus and the dynamic modulus,while dynamic viscosity defines cohesion and normal viscous stress.The effect of frequency on cohesion is considered.The initial stress state is defined by the minimum cohesion at the elastic limit when axial splitting can occur.However,as radial cracks grow,the stress state becomes oblique and moves towards the shear plane.The maximum and nonlinear cohesions are defined by the rock parameters under compressive strength when the radial crack depth reaches a critical value.The efficacy and precision of RDT are validated through the presentation of ultrasonic measurements on sandstone and rock specimens sourced from the literature.The results presented in dimensionless diagrams can be utilized in microcrack zones in the absence of lateral pressure in rock masses that have undergone disintegration due to excavation.展开更多
A series of acoustic emission(AE)-integrated conventional triaxial compression tests(CTTs)were conducted to evaluate the mechanical properties of hard red sandstone.Under conventional triaxial stress states,the crack ...A series of acoustic emission(AE)-integrated conventional triaxial compression tests(CTTs)were conducted to evaluate the mechanical properties of hard red sandstone.Under conventional triaxial stress states,the crack closure stress,crack initiation stress,and damage stress ranged in 13.75%-22.34%,31.84%-42.19%,and 63.85%-75.93%of the peak strength of sandstone,respectively.The AE parameters reflected the confining pressure(σ3)effect on microcrack propagation,withσ3=5 MPa identified as the threshold affecting both the timing of numerous AE hits and the distribution range of peak frequencies of AE signals before the final failure of each specimen.The AE property analysis showed that shear cracks played a dominant role in rock failure in CCTs,which ranged in 60%-85%of the total number of cracks.A smallerσ3 value promoted shear failure,whereas a largerσ3 value inhibited it.Furthermore,the appropriate dataset selection range to accurately calculate the cohesion force and internal friction angle in CTTs and variable-angle shear tests was determined.展开更多
The discourse marker ni hai bie shuo(你还别说)often appears at the beginning of a sentence,connecting to a rich variety of clause types.Its co-occurring words are mostly those expressing subjective evaluation.The subs...The discourse marker ni hai bie shuo(你还别说)often appears at the beginning of a sentence,connecting to a rich variety of clause types.Its co-occurring words are mostly those expressing subjective evaluation.The subsequent discourse it connects to mainly consists of three clause types:explanatory,resultative,and adversative.The basic semantic structure of the segment in which it appears is:(S1)+ni hai bie shuo+S2.It serves seven textual functions,such as the agreement function,negation function,reminding function,and topic-shifting function.展开更多
This study aims to investigate the failure modes at the interface of semi-flexible pavement(SFP)materials.The cohesive and wetting properties of asphalt materials,as well as two types of grout(early strength cement gr...This study aims to investigate the failure modes at the interface of semi-flexible pavement(SFP)materials.The cohesive and wetting properties of asphalt materials,as well as two types of grout(early strength cement grout-ELS and high strength cement grout-CHS),were evaluated through pull-out tests and contact angle experiments.The rheological properties of the grout/asphalt mortar were assessed using dynamic shear rheometer(DSR)testing.The interaction coefficient,complex shear modulus,and complex viscosity coefficients of the grout/asphalt mortar were calculated to analyze the interaction between the grout and asphalt.Failure modes were identified through image analysis of semi-circular bending test(SCB)specimens.Results indicate that ELS specimens exhibit a lower grout/asphalt interface failure ratio compared to CHS specimens,due to the superior wettability and interaction of ELS grout.As the temperature increases,the proportions of cement fracture and aggregate failure decrease,while the proportion of asphalt cohesive failure surfaces increases.Furthermore,the bonding strength of SBS-modified asphalt with the grout exceeds that of pure asphalt.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.
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BACKGROUND Colorectal signet-ring cell carcinoma(CSRCC)is a rare clinical entity which accounts for approximately 1%of all colorectal cancers.Although multiple studies concerning this specific topic have been published in the past decades,the pathogenesis,associated risk factors,and potential implications on treatment are still poorly understood.Besides the low incidence,historically confusing histological criteria have resulted in confusing data.Nevertheless,the rising incidence of CSRCC along with relatively young age at presentation and associated dismal prognosis,highlight the actual interest to synthesize the known literature regarding CSRCC.AIM To provide an updated overview of risk factors,prognosis,and management of CSRCC.METHODS A literature search in the MEDLINE/PubMed database was conducted with the following search terms used:‘Signet ring cell carcinoma’and‘colorectal’.Studies in English language,published after January 1980,were included.Studies included in the qualitative synthesis were evaluated for content concerning epidemiology,risk factors,and clinical,diagnostic,histological,and molecular features,as well as metastatic pattern and therapeutic management.If possible,presented data was extracted in order to present a more detailed overview of the literature.RESULTS In total,67 articles were included for qualitative analysis,of which 54 were eligible for detailed data extraction.CSRCC has a reported incidence between 0.1%-2.4%and frequently presents with advanced disease stage at the time of diagnosis.CSRCC is associated with an impaired overall survival(5-year OS:0%-46%)and a worse stagecorrected outcome compared to mucinous and not otherwise specified adenocarcinoma.The systematic use of exploratory laparoscopy to determine the presence of peritoneal metastases has been advised.Surgery is the mainstay of treatment,although the rates of curative resection in CSRCC(21%-82%)are lower compared to those in other histological types.In case of peritoneal metastasis,cytoreductive surgery with hyperthermic intraperitoneal chemotherapy should only be proposed in selected patients.CONCLUSION CSRCC is a rare clinical entity most often characterized by young age and advanced disease at presentation.As such,diagnostic modalities and therapeutic approach should be tailored accordingly.
文摘Under the guidance of Systemic-Functional Grammar(SFG),cohesion is applied to analyze the selected context.Cohesion plays a great role in organizing a whole context and it can be further divided into grammatical cohesion and lexical cohesion.Main ideas of cohesion are illustrated and made it for application,which employs British children's literature-The Water Babies as the object.The research method adopted here is mainly quantitative.Through analyzing selected sections,it is obvious that cohesion helps readers understand the contexts better.Besides,the use of cohesion makes the context more precise and compact.For context,the role of cohesion is irreplaceable.
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.
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.
基金supported by the National Natural Science Foundation of China(Nos.52371128,52304378,52101031 and 92163107).
文摘Grain boundary engineering plays a significant role in the improvement of strength and plasticity of alloys. However, in refractory high-entropy alloys, the susceptibility of grain boundaries to oxygen presents a bottleneck in achieving high mechanical performance. Creating a large number of clean grain boundaries in refractory high-entropy alloys is a challenge. In this study, an ultrafine-grained (UFG) NbMoTaW alloy with high grain-boundary cohesion was prepared by powder metallurgy, taking advantages of rapid hot-pressing sintering and full-process inert atmosphere protection from powder synthesis to sintering. By oxygen control and an increase in the proportion of grain boundaries, the segregation of oxygen and formation of oxides at grain boundaries were strongly mitigated, thus the intrinsic high cohesion of the interfaces was preserved. Compared to the coarse-grained alloys prepared by arc-melting and those sintered by traditional powder metallurgy methods, the UFG NbMoTaW alloy demonstrated simultaneously increased strength and plasticity at ambient temperature. The highly cohesive grain boundaries not only reduce brittle fractures effectively but also promote intragranular deformation. Consequently, the UFG NbMoTaW alloy achieved a high yield strength even at elevated temperatures, with a remarkable performance of 1117 MPa at 1200 ℃. This work provides a feasible solution for producing refractory high-entropy alloys with low impurity content, refined microstructure, and excellent mechanical performance.
基金Project supported by the National Natural Science Foundation of China(No.42202314)。
文摘A coupled thermal-hydro-mechanical cohesive phase-field model for hydraulic fracturing in deep coal seams is presented.Heat exchange between the cold fluid and the hot rock is considered,and the thermal contribution terms between the cold fluid and the hot rock are derived.Heat transfer obeys Fourier's law,and porosity is used to relate the thermodynamic parameters of the fracture and matrix domains.The net pressure difference between the fracture and the matrix is neglected,and thus the fluid flow is modeled by the unified fluid-governing equations.The evolution equations of porosity and Biot's coefficient during hydraulic fracturing are derived from their definitions.The effect of coal cleats is considered and modeled by Voronoi polygons,and this approach is shown to have high accuracy.The accuracy of the proposed model is verified by two sets of fracturing experiments in multilayer coal seams.Subsequently,the differences in fracture morphology,fluid pressure response,and fluid pressure distribution between direct fracturing of coal seams and indirect fracturing of shale interlayers are explored,and the effects of the cluster number and cluster spacing on fracture morphology for multi-cluster fracturing are also examined.The numerical results show that the proposed model is expected to be a powerful tool for the fracturing design and optimization of deep coalbed methane.
基金supported by grants from the Natural Science Foundation of Fujian Province(2021J011062)Minjiang Scholars Funding(GY-633Z21067).
文摘This study investigates the bond performance at the interfacial region shared by Ultra-High Performance Concrete(UHPC)and steel tubes through push-out tests.This study examines how changes in steel fiber volumetric ratio and thickness of steel tube influence the bond strength characteristics.The results show that as the enhancement of the steel tube wall thickness,the ultimate bond strength at the interface improves significantly,whereas the initial bond strength exhibits only slight variations.The influence of steel fiber volumetric ratio presents a nonlinear trend,with initial bond strength decreasing at low fiber content and increasing significantly as fiber content rises.Additionally,finite element(FE)simulations were applied to replicate the experimental conditions,and the outcomes showed strong correlation with the experimental data,confirming the exactitude of the FE model in predicting the bond behavior at the UHPC-Steel interface.These findings provide valuable insights for optimizing the design of UHPC-Filled steel tubes in high-performance structure.
文摘1.A.Mertha,“‘Stressing Out’:Cadre Calibration and Affective Proximity to the CCP in Reform-Era China”,The China Quarterly,Vol.229,2017,pp.64-85.2.B.L.McCormick,“Book Review of‘The Chinese Communist Party's Capacity to Rule:Ideology,Legitimacy and Party Cohesion’”,The China Journal,Vol.77,2017,pp.161-163.
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This paper investigates the mechanisms of rock failure related to axial splitting and shear failure due to hoop stresses in cylindrical specimens.The hoop stresses are caused by normal viscous stress.The rheological dynamics theory(RDT)is used,with the mechanical parameters being determined by P-and S-wave velocities.The angle of internal friction is determined by the ratio of Young's modulus and the dynamic modulus,while dynamic viscosity defines cohesion and normal viscous stress.The effect of frequency on cohesion is considered.The initial stress state is defined by the minimum cohesion at the elastic limit when axial splitting can occur.However,as radial cracks grow,the stress state becomes oblique and moves towards the shear plane.The maximum and nonlinear cohesions are defined by the rock parameters under compressive strength when the radial crack depth reaches a critical value.The efficacy and precision of RDT are validated through the presentation of ultrasonic measurements on sandstone and rock specimens sourced from the literature.The results presented in dimensionless diagrams can be utilized in microcrack zones in the absence of lateral pressure in rock masses that have undergone disintegration due to excavation.
基金partially supported by the National Natural Science Foundation of China(No.52104112)the Science and Technology Innovation Program of Hunan Province,China(Nos.2021RC3007,2020RC3090)by the Fundamental Research Funds for the Central Universities of Central South University,China(No.2024ZZTS0060)。
文摘A series of acoustic emission(AE)-integrated conventional triaxial compression tests(CTTs)were conducted to evaluate the mechanical properties of hard red sandstone.Under conventional triaxial stress states,the crack closure stress,crack initiation stress,and damage stress ranged in 13.75%-22.34%,31.84%-42.19%,and 63.85%-75.93%of the peak strength of sandstone,respectively.The AE parameters reflected the confining pressure(σ3)effect on microcrack propagation,withσ3=5 MPa identified as the threshold affecting both the timing of numerous AE hits and the distribution range of peak frequencies of AE signals before the final failure of each specimen.The AE property analysis showed that shear cracks played a dominant role in rock failure in CCTs,which ranged in 60%-85%of the total number of cracks.A smallerσ3 value promoted shear failure,whereas a largerσ3 value inhibited it.Furthermore,the appropriate dataset selection range to accurately calculate the cohesion force and internal friction angle in CTTs and variable-angle shear tests was determined.
文摘The discourse marker ni hai bie shuo(你还别说)often appears at the beginning of a sentence,connecting to a rich variety of clause types.Its co-occurring words are mostly those expressing subjective evaluation.The subsequent discourse it connects to mainly consists of three clause types:explanatory,resultative,and adversative.The basic semantic structure of the segment in which it appears is:(S1)+ni hai bie shuo+S2.It serves seven textual functions,such as the agreement function,negation function,reminding function,and topic-shifting function.
基金Funded by the Science and Technology Program Special Fund of Jiangsu Province(Frontier Leading Technology Basic Research)Major Projects(No.BK20222004)the National Natural Science Foundation of China(No.52078241)the New Cornerstone Science Foundation through the XPLORER PRIZE。
文摘This study aims to investigate the failure modes at the interface of semi-flexible pavement(SFP)materials.The cohesive and wetting properties of asphalt materials,as well as two types of grout(early strength cement grout-ELS and high strength cement grout-CHS),were evaluated through pull-out tests and contact angle experiments.The rheological properties of the grout/asphalt mortar were assessed using dynamic shear rheometer(DSR)testing.The interaction coefficient,complex shear modulus,and complex viscosity coefficients of the grout/asphalt mortar were calculated to analyze the interaction between the grout and asphalt.Failure modes were identified through image analysis of semi-circular bending test(SCB)specimens.Results indicate that ELS specimens exhibit a lower grout/asphalt interface failure ratio compared to CHS specimens,due to the superior wettability and interaction of ELS grout.As the temperature increases,the proportions of cement fracture and aggregate failure decrease,while the proportion of asphalt cohesive failure surfaces increases.Furthermore,the bonding strength of SBS-modified asphalt with the grout exceeds that of pure asphalt.
