There exist differences between the usages of prepositions in English and Chinese, not only for the different cultural backgrounds, but for the different cognitive models. The use of English prepositions is a great ch...There exist differences between the usages of prepositions in English and Chinese, not only for the different cultural backgrounds, but for the different cognitive models. The use of English prepositions is a great challenge for Chinese English learners (CELs). This essay discusses the misuse of the English spatial preposition IN by CELs, using the data collected from Chinese Learner English Corpus (CLEC) against other corpora such as BNC, FLOB, FROWN as reference corpora. The statistical data, such as Frequency and Type/Token Ratio (TTR) of IN, shows that the overuse of IN is typical for Chinese English learners, and it also offers a reasonable explanation for the misuse of IN using the image schema in cognitive metaphor theory (CMT). The polysemy of the spatial preposition IN can be divided into different image schemas. Chinese English learners can avoid preposition misuse with the help of image-schemas.展开更多
盾构隧道的管片上浮作为施工过程中监测的重要部分,施工过程中的同步注浆过程,其压力影响和浆液的抗浮力影响着隧道上浮,直接关系到隧道施工与运营的安全性和稳定性。本文以基于固废的剪切型浆液为例,基于浆液性能实测数据、理论模型与...盾构隧道的管片上浮作为施工过程中监测的重要部分,施工过程中的同步注浆过程,其压力影响和浆液的抗浮力影响着隧道上浮,直接关系到隧道施工与运营的安全性和稳定性。本文以基于固废的剪切型浆液为例,基于浆液性能实测数据、理论模型与数值模拟方法,研究了在黏性土中同步注浆中注浆压力和浆液抗剪影响下,浆液对隧道结构以及自身的应力分布规律。研究通过非牛顿流体的流变特性理论,分析了隧道施工过程中同步注浆浆液性能对于结构内力分布和变形的影响,探讨了剪切型砂浆中浆液性能参数对于隧道施工的影响。结果表明:(1) 剪切型砂浆的强度参数在隧道抵抗上浮中起着关键作用,泥浆的动力粘度与浆液的强度都有利抗浮;(2) 适当控制施工参数可以有效降低注浆过程中对于结构的扰动与上浮;(3) 数值模拟揭示了盾构隧道施工过程中同步注浆的压力分布规律,为优化注浆过程提供了重要依据。本文研究成果不仅为类似的隧道工程注浆系统设计与施工提供技术参考,还为浆液性能的优化与结构的长期上浮预测提供了理论基础。The floating of tunnel segments in shield tunneling is an important part of construction monitoring. During synchronous grouting in shield tunnel construction, monitoring tunnel uplift, as grouting pressure and the anti-buoyancy properties of the slurry significantly influence this uplift, directly affecting the safety and stability of tunnel construction and operation. This paper takes shear-type grout based on solid waste as an example. Based on the measured data of grout properties, theoretical models, and numerical simulation methods, it investigates the stress distribution patterns of the grout on the tunnel structure and within itself under the influence of slurry pressure and grout shear resistance during synchronous grouting in cohesive soil. By analyzing the rheological characteristics of non-Newtonian fluids, the study examines the influence of synchronous grouting grout properties on the internal force distribution and deformation of the tunnel structure during construction and explores the impact of grout property parameters in shear-type mortar on tunnel construction. The results show that: (1) The strength parameters of shear-type mortar play a key role in the tunnel's resistance to floating, with both the dynamic viscosity of the slurry and the strength of the grout contributing to anti-floating;(2) Proper control of construction parameters can effectively reduce the disturbance and floating of the structure during grouting;(3) Numerical simulation reveals the pressure distribution patterns of synchronous grouting during shield tunneling construction, providing an important basis for optimizing the grouting process. The research findings of this paper not only offer technical references for the design and construction of grouting systems in similar tunnel projects but also provide a theoretical foundation for the optimization of grout properties and long-term prediction of tunnel floating.展开更多
To address the problems of low accuracy by the CONWEP model and poor efficiency by the Coupled Eulerian-Lagrangian(CEL)method in predicting close-range air blast loads of cylindrical charges,a neural network-based sim...To address the problems of low accuracy by the CONWEP model and poor efficiency by the Coupled Eulerian-Lagrangian(CEL)method in predicting close-range air blast loads of cylindrical charges,a neural network-based simulation(NNS)method with higher accuracy and better efficiency was proposed.The NNS method consisted of three main steps.First,the parameters of blast loads,including the peak pressures and impulses of cylindrical charges with different aspect ratios(L/D)at different stand-off distances and incident angles were obtained by two-dimensional numerical simulations.Subsequently,incident shape factors of cylindrical charges with arbitrary aspect ratios were predicted by a neural network.Finally,reflected shape factors were derived and implemented into the subroutine of the ABAQUS code to modify the CONWEP model,including modifications of impulse and overpressure.The reliability of the proposed NNS method was verified by related experimental results.Remarkable accuracy improvement was acquired by the proposed NNS method compared with the unmodified CONWEP model.Moreover,huge efficiency superiority was obtained by the proposed NNS method compared with the CEL method.The proposed NNS method showed good accuracy when the scaled distance was greater than 0.2 m/kg^(1/3).It should be noted that there is no need to generate a new dataset again since the blast loads satisfy the similarity law,and the proposed NNS method can be directly used to simulate the blast loads generated by different cylindrical charges.The proposed NNS method with high efficiency and accuracy can be used as an effective method to analyze the dynamic response of structures under blast loads,and it has significant application prospects in designing protective structures.展开更多
Numerous former military sites worldwide require environmental cleanup from buried unexploded ordnance(UxO)that pose hazards such as leaching toxic chemicals and explosion risks.However,selecting the appropriate mitig...Numerous former military sites worldwide require environmental cleanup from buried unexploded ordnance(UxO)that pose hazards such as leaching toxic chemicals and explosion risks.However,selecting the appropriate mitigation technology relies on prior knowledge of UxO depth of burial(DoB)at specific sites.This study utilizes numerical simulations,employing large deformation explicit finite element(LDEFE)analysis and the Coupled Eulerian-Lagrangian(CEL)approach,to model the penetration of ordnances into clay targets.A modified Tresca constitutive model is implemented in ABAQUS software to capture key features of clay behavior under high strain rate(HSR)loading.The role of various parameters on DoB is investigated,including undrained shear strength,stiffness,and density of the soil.The findings highlight the paramount importance of undrained shear strength in clayey soil penetrability,in addition to the role of soil stiffness,and density.The simulations were employed to calibrate model parameters for Young's empirical penetration model,as well as the Poncelet phenomenological penetration model,demonstrating the efficacy of the numerical simulations in extrapolating its findings within the relevant parameter space.In particular,the calibrated parameters of Young's and Poncelet's models can be identified as a direct function of the various discussed soil properties,which was previously unavailable.展开更多
P2-type layered oxide Na_(2/3)Ni_(1/3)Mn_(2/3)O_(2)(NM)is a promising cathode material for sodium-ion batteries(SIBs).However,the severe irreversible phase transition,sluggish Na+diffusion kinetics,and interfacial sid...P2-type layered oxide Na_(2/3)Ni_(1/3)Mn_(2/3)O_(2)(NM)is a promising cathode material for sodium-ion batteries(SIBs).However,the severe irreversible phase transition,sluggish Na+diffusion kinetics,and interfacial side reactions at high-voltage result in grievous capacity degradation and inferior electrochemical performance.Herein,a dual-function strategy of entropy tuning and artificial cathode electrolyte interface(CEI)layer construction is reported to generate a novel P2-type medium-entropy Na_(0.75)Li_(0.1)Mg_(0.05)Ni_(0.18)Mn_(0.66)Ta_(0.01)O_(2)with NaTaO_(3)surface modification(LMNMT)to address the aforementioned issues.In situ X-ray diffraction reveals that LMNMT exhibits a near zero-strain phase transition with a volume change of only 1.4%,which is significantly lower than that of NM(20.9%),indicating that entropy tuning effectively suppresses irreversible phase transitions and enhances ion diffusion.Kinetic analysis and post-cycling interfacial characterization further confirm that the artificial CEI layer promotes the formation of a stable,thin NaF-rich CEI and reduces interfacial side reactions,thereby further enhancing ion transport kinetics and surface/interface stability.Consequently,the LMNMT electrode exhibits outstanding rate capability(46 mA h g^(−1)at 20 C)and cycling stability(89.5%capacity retention after 200 cycles at 2 C)within the voltage range of 2–4.35 V.The LMNMT also exhibits superior all-climate performance and air stability.This study provides a novel path for the design of high-voltage cathode materials for SIBs.展开更多
文摘There exist differences between the usages of prepositions in English and Chinese, not only for the different cultural backgrounds, but for the different cognitive models. The use of English prepositions is a great challenge for Chinese English learners (CELs). This essay discusses the misuse of the English spatial preposition IN by CELs, using the data collected from Chinese Learner English Corpus (CLEC) against other corpora such as BNC, FLOB, FROWN as reference corpora. The statistical data, such as Frequency and Type/Token Ratio (TTR) of IN, shows that the overuse of IN is typical for Chinese English learners, and it also offers a reasonable explanation for the misuse of IN using the image schema in cognitive metaphor theory (CMT). The polysemy of the spatial preposition IN can be divided into different image schemas. Chinese English learners can avoid preposition misuse with the help of image-schemas.
文摘盾构隧道的管片上浮作为施工过程中监测的重要部分,施工过程中的同步注浆过程,其压力影响和浆液的抗浮力影响着隧道上浮,直接关系到隧道施工与运营的安全性和稳定性。本文以基于固废的剪切型浆液为例,基于浆液性能实测数据、理论模型与数值模拟方法,研究了在黏性土中同步注浆中注浆压力和浆液抗剪影响下,浆液对隧道结构以及自身的应力分布规律。研究通过非牛顿流体的流变特性理论,分析了隧道施工过程中同步注浆浆液性能对于结构内力分布和变形的影响,探讨了剪切型砂浆中浆液性能参数对于隧道施工的影响。结果表明:(1) 剪切型砂浆的强度参数在隧道抵抗上浮中起着关键作用,泥浆的动力粘度与浆液的强度都有利抗浮;(2) 适当控制施工参数可以有效降低注浆过程中对于结构的扰动与上浮;(3) 数值模拟揭示了盾构隧道施工过程中同步注浆的压力分布规律,为优化注浆过程提供了重要依据。本文研究成果不仅为类似的隧道工程注浆系统设计与施工提供技术参考,还为浆液性能的优化与结构的长期上浮预测提供了理论基础。The floating of tunnel segments in shield tunneling is an important part of construction monitoring. During synchronous grouting in shield tunnel construction, monitoring tunnel uplift, as grouting pressure and the anti-buoyancy properties of the slurry significantly influence this uplift, directly affecting the safety and stability of tunnel construction and operation. This paper takes shear-type grout based on solid waste as an example. Based on the measured data of grout properties, theoretical models, and numerical simulation methods, it investigates the stress distribution patterns of the grout on the tunnel structure and within itself under the influence of slurry pressure and grout shear resistance during synchronous grouting in cohesive soil. By analyzing the rheological characteristics of non-Newtonian fluids, the study examines the influence of synchronous grouting grout properties on the internal force distribution and deformation of the tunnel structure during construction and explores the impact of grout property parameters in shear-type mortar on tunnel construction. The results show that: (1) The strength parameters of shear-type mortar play a key role in the tunnel's resistance to floating, with both the dynamic viscosity of the slurry and the strength of the grout contributing to anti-floating;(2) Proper control of construction parameters can effectively reduce the disturbance and floating of the structure during grouting;(3) Numerical simulation reveals the pressure distribution patterns of synchronous grouting during shield tunneling construction, providing an important basis for optimizing the grouting process. The research findings of this paper not only offer technical references for the design and construction of grouting systems in similar tunnel projects but also provide a theoretical foundation for the optimization of grout properties and long-term prediction of tunnel floating.
基金financially supported by the National Natural Science Foundation of China(Grant Nos.52271317 and 52071149)the Fundamental Research Funds for the Central Universities(HUST:2019kfy XJJS007)。
文摘To address the problems of low accuracy by the CONWEP model and poor efficiency by the Coupled Eulerian-Lagrangian(CEL)method in predicting close-range air blast loads of cylindrical charges,a neural network-based simulation(NNS)method with higher accuracy and better efficiency was proposed.The NNS method consisted of three main steps.First,the parameters of blast loads,including the peak pressures and impulses of cylindrical charges with different aspect ratios(L/D)at different stand-off distances and incident angles were obtained by two-dimensional numerical simulations.Subsequently,incident shape factors of cylindrical charges with arbitrary aspect ratios were predicted by a neural network.Finally,reflected shape factors were derived and implemented into the subroutine of the ABAQUS code to modify the CONWEP model,including modifications of impulse and overpressure.The reliability of the proposed NNS method was verified by related experimental results.Remarkable accuracy improvement was acquired by the proposed NNS method compared with the unmodified CONWEP model.Moreover,huge efficiency superiority was obtained by the proposed NNS method compared with the CEL method.The proposed NNS method showed good accuracy when the scaled distance was greater than 0.2 m/kg^(1/3).It should be noted that there is no need to generate a new dataset again since the blast loads satisfy the similarity law,and the proposed NNS method can be directly used to simulate the blast loads generated by different cylindrical charges.The proposed NNS method with high efficiency and accuracy can be used as an effective method to analyze the dynamic response of structures under blast loads,and it has significant application prospects in designing protective structures.
基金the support of the Strategic Environmental Research and Development Program(SERDP)of the United States of America(Grant No.MR23-3855).
文摘Numerous former military sites worldwide require environmental cleanup from buried unexploded ordnance(UxO)that pose hazards such as leaching toxic chemicals and explosion risks.However,selecting the appropriate mitigation technology relies on prior knowledge of UxO depth of burial(DoB)at specific sites.This study utilizes numerical simulations,employing large deformation explicit finite element(LDEFE)analysis and the Coupled Eulerian-Lagrangian(CEL)approach,to model the penetration of ordnances into clay targets.A modified Tresca constitutive model is implemented in ABAQUS software to capture key features of clay behavior under high strain rate(HSR)loading.The role of various parameters on DoB is investigated,including undrained shear strength,stiffness,and density of the soil.The findings highlight the paramount importance of undrained shear strength in clayey soil penetrability,in addition to the role of soil stiffness,and density.The simulations were employed to calibrate model parameters for Young's empirical penetration model,as well as the Poncelet phenomenological penetration model,demonstrating the efficacy of the numerical simulations in extrapolating its findings within the relevant parameter space.In particular,the calibrated parameters of Young's and Poncelet's models can be identified as a direct function of the various discussed soil properties,which was previously unavailable.
基金supported by the National Natural Science Foundation of China(52272295,52071137,51977071,51802040,and 21802020)the Science and Technology Innovation Program of Hunan Province(2021RC3066 and 2021RC3067)+2 种基金the Natural Science Foundation of Hunan Province(2020JJ3004 and 2020JJ4192)Graduate Research Innovation Project of Hunan Province(CX20240456 and CX20240405)N.Zhang and X.Xie also acknowledge the financial support of the Fundamental Research Funds for the Central。
文摘P2-type layered oxide Na_(2/3)Ni_(1/3)Mn_(2/3)O_(2)(NM)is a promising cathode material for sodium-ion batteries(SIBs).However,the severe irreversible phase transition,sluggish Na+diffusion kinetics,and interfacial side reactions at high-voltage result in grievous capacity degradation and inferior electrochemical performance.Herein,a dual-function strategy of entropy tuning and artificial cathode electrolyte interface(CEI)layer construction is reported to generate a novel P2-type medium-entropy Na_(0.75)Li_(0.1)Mg_(0.05)Ni_(0.18)Mn_(0.66)Ta_(0.01)O_(2)with NaTaO_(3)surface modification(LMNMT)to address the aforementioned issues.In situ X-ray diffraction reveals that LMNMT exhibits a near zero-strain phase transition with a volume change of only 1.4%,which is significantly lower than that of NM(20.9%),indicating that entropy tuning effectively suppresses irreversible phase transitions and enhances ion diffusion.Kinetic analysis and post-cycling interfacial characterization further confirm that the artificial CEI layer promotes the formation of a stable,thin NaF-rich CEI and reduces interfacial side reactions,thereby further enhancing ion transport kinetics and surface/interface stability.Consequently,the LMNMT electrode exhibits outstanding rate capability(46 mA h g^(−1)at 20 C)and cycling stability(89.5%capacity retention after 200 cycles at 2 C)within the voltage range of 2–4.35 V.The LMNMT also exhibits superior all-climate performance and air stability.This study provides a novel path for the design of high-voltage cathode materials for SIBs.
