In comparison to discrete descriptions of fracture process,the recently proposed phase field methodology averts the numerical tracking strategy of discontinuities in solids,which enables the numerical implement simpli...In comparison to discrete descriptions of fracture process,the recently proposed phase field methodology averts the numerical tracking strategy of discontinuities in solids,which enables the numerical implement simplification.An implicit finite element formulation based on the diffuse phase field is extended for stable and efficient analysis of complex dynamic fracture process in ductile solids.This exhibited formulation is shown to capture entire range of the characteristics of ductile material presenting J2-plasticity,embracing plasticization,cracks initiation,propagation,branching and merging while fulfilling the basic principle of thermodynamics.Herein,we implement a staggered time integration scheme of the dynamic elasto-plastic phase field method into the commercial finite element code.The numerical performance of the present advanced phase field model has been examined through several classic dynamic fracture benchmarks,and in all cases simulation results are in good agreement with the associated experimental data and other numerical results in previous literature.展开更多
Erik Verlinde recently proposed an idea about the thermodynamic origin of gravity.Though this is abeautiful idea, which may resolve many long standing problems in the theories of gravity, it also raises many otherprob...Erik Verlinde recently proposed an idea about the thermodynamic origin of gravity.Though this is abeautiful idea, which may resolve many long standing problems in the theories of gravity, it also raises many otherproblems.In this article I will comment on some of the problems of Verlinde’s proposal with special emphasis on thethermodynamical origin of the principle of relativity.It is found that there is a large group of hidden symmetries ofthermodynamics, which contains the Poincare group of the spacetime for which space is emergent.This explains thethermodynamic origin of the principle of relativity.展开更多
Experience includes explicit and tacit knowledge. Explicit knowledge is from a person＇s ＂espoused theory＂ which is what a person believes and claims to follow. Tacit knowledge is from a person＇s ＂theory-in-use＂ ...Experience includes explicit and tacit knowledge. Explicit knowledge is from a person＇s ＂espoused theory＂ which is what a person believes and claims to follow. Tacit knowledge is from a person＇s ＂theory-in-use＂ which lies behind a person＇s action or behavior. The knowledge of teaching demonstrated in the classroom can be referred to as tacit knowledge or theory-in-use which is often the theory behind the practice of experienced teachers. Freema Elbaz （1983） points out that the ＂experience＂ is referred to as ＂practical knowledge＂, which ＂provides the basis for a conceptualization which sees the teacher as possessing valuable resources＂ （6） and allows teachers to explicitly indicate and tacitly demonstrate their experience in teaching. The purpose of the study is to investigate how experienced college instructors apply their good teaching qualities to teaching social studies. The participants are three experienced college instructors teaching social studies. A concept map and a final reflection are used to elicit experienced instructors＇ personal epistemology in teaching social studies and their perception of technology use in the classroom. Each participant was asked to generate nine good teaching qualities and draw their concept map based on the nine qualities. Their concept maps reflected their theory-in-use and showed the relationship among their teaching qualities by displaying them together in a graphic form and how each teaching quality is connected to another. Participants＇ technology use was also explored to get their perception of the role of technology and their actual use of it in teaching. Then they were asked to validate their concept map data and reflect on their classroom teaching and use of technology. The findings show the three instructors taught under different schema and decided what their means and ends should be and how technology can help facilitate teaching and learning. However, most of them seemed to treat the content （e.g., democracy education） as their ends and thus used pedagogy （e.g., technology） as the means to reach the ends. Their technology use also reflected their perception of technology in teaching and revealed their limited understanding of technology integration, which leads to potential problems.展开更多
Cancer cell dormancy is the main cause of cancer recurrence and failure of therapy as dormant cells evade not only the anticancer drugs but also the host immune system. These dormant cells veil themselves from detecti...Cancer cell dormancy is the main cause of cancer recurrence and failure of therapy as dormant cells evade not only the anticancer drugs but also the host immune system. These dormant cells veil themselves from detection by imaging and/or using biomarkers, which imposes an additional problem in targeting such cells. A similar form of hibernation process known as encystation is studied in detail for pathogenic unicellular eukaryotic microorganisms. By examination using microarray gene expression profiles, immunocytochemistry tools, and siRNAs during the process of encystation, understanding the covert features of cancer cell dormancy as proposed could be possible. This knowledge can be extended to dormant cancer cells to uncover the mechanisms that underlie this ghost, yet dangerous state of human cancers. We propose a strategy to induce dormancy and exit this state by application of knowledge gained from the encystation induction and retrieval processes in pathogenic eukaryotic microorganisms. Given that early detection and characterization of dormant malignant tumor cells is important as a general strategy to monitor and prevent the development of overt metastatic disease, this homology may enable the design of therapies that could either awake the dormant cell from dormancy to make it available for therapies or prolong such a phase to make cancer appear as a chronic disease展开更多
This paper discusses the issue of the hidden curriculum in the setting of a language classroom. The author first talks about the definition of the hidden curriculum from a theoretical perspective and proposes her own ...This paper discusses the issue of the hidden curriculum in the setting of a language classroom. The author first talks about the definition of the hidden curriculum from a theoretical perspective and proposes her own working definition. She then elaborates on the reasons and main manifestations of the hidden curriculum from the teachers＇ and learners＇ angles respectively with examples taken from language classrooms. Based on some profound reflections, some feasible suggestions on how to minimize the negative impacts of the hidden curriculum are suggested. On the basis of the previous discussion, the author reaches a conclusion： Language teachers should not avoid or ignore the hidden curriculum existing in the language teaching processes; rather, they are expected to face it positively and try their very best to solve the problems it brings. A sound attitude towards the hidden curriculum can help language teachers better understand and implement the formal or official curriculum made by the school or the state.展开更多
Conceptual metaphor has always been the study focus of cognitive linguistics. Conceptual metaphor is ubiquitous, cognitive and systematic. Nathaniel Hawthorne in his representative work The Scarlet Letter makes full u...Conceptual metaphor has always been the study focus of cognitive linguistics. Conceptual metaphor is ubiquitous, cognitive and systematic. Nathaniel Hawthorne in his representative work The Scarlet Letter makes full use of the conceptual metaphor. A detailed description of the heroine Hester Prynne through the conceptual metaphor fully expresses Nathaniel Hawthorne＇ s feminist thoughts. Through the metaphorical analyses of the name Pearl, the scarlet letter ＂A＂, the forest and the scaffold this paper analyzes Hester Prynne＇ s resistant consciousness. On the basis of this, the positive social significance of the novel is explored.展开更多
Objective It has long been reported that prolactinomas treated with bromocriptine increase fibrosis and may affect surgical outcomes.We retrospectively studied 238 consecutive patients with histopathologically confirm...Objective It has long been reported that prolactinomas treated with bromocriptine increase fibrosis and may affect surgical outcomes.We retrospectively studied 238 consecutive patients with histopathologically confirmed prolactinomas undergoing microsurgery in a single neurosurgery department of Tongji Hospital(Wuhan,China) from 2012 to 2015 in order to evaluate tumor consistency changes after bromocriptine pretreatment and surgical outcomes.Methods We divided the patients into four groups;males in the dopamine agonist(DA) group,females in the DA group,males in the no DA group,and females in the no DA group,and we compared the surgery process,specimen Masson staining,and clinical outcomes of the four groups.According to a previously published classification,the operative notes from an experienced neurosurgeon were reviewed to classify the consistency of tumors as "fibrous" or "nonfibrous".Results No differences in tumor consistency were found in male patients with or without DA treatment.However,in female patients with DA treatment,tumors were likely to be harder in texture than the tumors of female patients without DA treatment.Despite tumor consistency differences between sexes,the tumor biological remission rate was similar between groups,as was the rate of tumor resection.Discussion Our study indicates that preoperative DA therapy impacts tumor consistency in female patients but not male patients.Although the surgical and histopathological outcomes are not influenced,these findings may provide useful information for the choice of operative approach and surgery process for pituitary adenoma.展开更多
The grammar is an important part of English learning, but grammar learning has been a controversial topic in English learning profession, gone the process from worship to abandonment and then to a rational understandi...The grammar is an important part of English learning, but grammar learning has been a controversial topic in English learning profession, gone the process from worship to abandonment and then to a rational understanding. Firstly, this paper makes a brief introduction of the process, then introduces and discusses the significance, including sentence production, function of adjustment, fossilization solution, focusing on grammar phenomenon and grasping the components of language. Then, this paper presents two types of grammar, namely, tacit knowledge and explicit knowledge. Last, four approaches to obtain grammar ability are proposed.展开更多
We consider the approximate acoustic cloaking in an inhomogeneous isotropic background space.By employing transformation media,together with the use of a sound-soft layer lining right outside the cloaked region,we sho...We consider the approximate acoustic cloaking in an inhomogeneous isotropic background space.By employing transformation media,together with the use of a sound-soft layer lining right outside the cloaked region,we show that one can achieve the near-invisibility by the"blow-up-a-small-region"construction.This is based on novel scattering estimates corresponding to multiple multi-scale obstacles located in an isotropic space.We develop a novel system of integral equations to decouple the nonlinear scattering interaction among the small obstacle components,the regular obstacle components and the inhomogeneous background medium.展开更多
Neural networks have been applied in various fields from signal processing, pattern recognition, associative memory to artifi- cial intelligence. Recently, nanoscale memristor has renewed interest in experimental real...Neural networks have been applied in various fields from signal processing, pattern recognition, associative memory to artifi- cial intelligence. Recently, nanoscale memristor has renewed interest in experimental realization of neural network. A neural network with a memristive synaptic weight is studied in this work. Dynamical properties of the proposed neural network are investigated through phase portraits, Poincar6 map, and Lyapunov exponents. Interestingly, the memristive neural network can generate hyperchaotic attractors without the presence of equilibrium points. Moreover, circuital implementation of such memristive neural network is presented to show its feasibility.展开更多
基金supported by the Na⁃tional Natural Science Foundation of China(No.12302176).
文摘In comparison to discrete descriptions of fracture process,the recently proposed phase field methodology averts the numerical tracking strategy of discontinuities in solids,which enables the numerical implement simplification.An implicit finite element formulation based on the diffuse phase field is extended for stable and efficient analysis of complex dynamic fracture process in ductile solids.This exhibited formulation is shown to capture entire range of the characteristics of ductile material presenting J2-plasticity,embracing plasticization,cracks initiation,propagation,branching and merging while fulfilling the basic principle of thermodynamics.Herein,we implement a staggered time integration scheme of the dynamic elasto-plastic phase field method into the commercial finite element code.The numerical performance of the present advanced phase field model has been examined through several classic dynamic fracture benchmarks,and in all cases simulation results are in good agreement with the associated experimental data and other numerical results in previous literature.
基金Supported by the National Natural Science Foundation of China under Grant No.10875059
文摘Erik Verlinde recently proposed an idea about the thermodynamic origin of gravity.Though this is abeautiful idea, which may resolve many long standing problems in the theories of gravity, it also raises many otherproblems.In this article I will comment on some of the problems of Verlinde’s proposal with special emphasis on thethermodynamical origin of the principle of relativity.It is found that there is a large group of hidden symmetries ofthermodynamics, which contains the Poincare group of the spacetime for which space is emergent.This explains thethermodynamic origin of the principle of relativity.
文摘Experience includes explicit and tacit knowledge. Explicit knowledge is from a person＇s ＂espoused theory＂ which is what a person believes and claims to follow. Tacit knowledge is from a person＇s ＂theory-in-use＂ which lies behind a person＇s action or behavior. The knowledge of teaching demonstrated in the classroom can be referred to as tacit knowledge or theory-in-use which is often the theory behind the practice of experienced teachers. Freema Elbaz （1983） points out that the ＂experience＂ is referred to as ＂practical knowledge＂, which ＂provides the basis for a conceptualization which sees the teacher as possessing valuable resources＂ （6） and allows teachers to explicitly indicate and tacitly demonstrate their experience in teaching. The purpose of the study is to investigate how experienced college instructors apply their good teaching qualities to teaching social studies. The participants are three experienced college instructors teaching social studies. A concept map and a final reflection are used to elicit experienced instructors＇ personal epistemology in teaching social studies and their perception of technology use in the classroom. Each participant was asked to generate nine good teaching qualities and draw their concept map based on the nine qualities. Their concept maps reflected their theory-in-use and showed the relationship among their teaching qualities by displaying them together in a graphic form and how each teaching quality is connected to another. Participants＇ technology use was also explored to get their perception of the role of technology and their actual use of it in teaching. Then they were asked to validate their concept map data and reflect on their classroom teaching and use of technology. The findings show the three instructors taught under different schema and decided what their means and ends should be and how technology can help facilitate teaching and learning. However, most of them seemed to treat the content （e.g., democracy education） as their ends and thus used pedagogy （e.g., technology） as the means to reach the ends. Their technology use also reflected their perception of technology in teaching and revealed their limited understanding of technology integration, which leads to potential problems.
文摘Cancer cell dormancy is the main cause of cancer recurrence and failure of therapy as dormant cells evade not only the anticancer drugs but also the host immune system. These dormant cells veil themselves from detection by imaging and/or using biomarkers, which imposes an additional problem in targeting such cells. A similar form of hibernation process known as encystation is studied in detail for pathogenic unicellular eukaryotic microorganisms. By examination using microarray gene expression profiles, immunocytochemistry tools, and siRNAs during the process of encystation, understanding the covert features of cancer cell dormancy as proposed could be possible. This knowledge can be extended to dormant cancer cells to uncover the mechanisms that underlie this ghost, yet dangerous state of human cancers. We propose a strategy to induce dormancy and exit this state by application of knowledge gained from the encystation induction and retrieval processes in pathogenic eukaryotic microorganisms. Given that early detection and characterization of dormant malignant tumor cells is important as a general strategy to monitor and prevent the development of overt metastatic disease, this homology may enable the design of therapies that could either awake the dormant cell from dormancy to make it available for therapies or prolong such a phase to make cancer appear as a chronic disease
文摘This paper discusses the issue of the hidden curriculum in the setting of a language classroom. The author first talks about the definition of the hidden curriculum from a theoretical perspective and proposes her own working definition. She then elaborates on the reasons and main manifestations of the hidden curriculum from the teachers＇ and learners＇ angles respectively with examples taken from language classrooms. Based on some profound reflections, some feasible suggestions on how to minimize the negative impacts of the hidden curriculum are suggested. On the basis of the previous discussion, the author reaches a conclusion： Language teachers should not avoid or ignore the hidden curriculum existing in the language teaching processes; rather, they are expected to face it positively and try their very best to solve the problems it brings. A sound attitude towards the hidden curriculum can help language teachers better understand and implement the formal or official curriculum made by the school or the state.
文摘Conceptual metaphor has always been the study focus of cognitive linguistics. Conceptual metaphor is ubiquitous, cognitive and systematic. Nathaniel Hawthorne in his representative work The Scarlet Letter makes full use of the conceptual metaphor. A detailed description of the heroine Hester Prynne through the conceptual metaphor fully expresses Nathaniel Hawthorne＇ s feminist thoughts. Through the metaphorical analyses of the name Pearl, the scarlet letter ＂A＂, the forest and the scaffold this paper analyzes Hester Prynne＇ s resistant consciousness. On the basis of this, the positive social significance of the novel is explored.
基金Supported by a grant from the National Natural Sciences Foundation of China(No.81270865)
文摘Objective It has long been reported that prolactinomas treated with bromocriptine increase fibrosis and may affect surgical outcomes.We retrospectively studied 238 consecutive patients with histopathologically confirmed prolactinomas undergoing microsurgery in a single neurosurgery department of Tongji Hospital(Wuhan,China) from 2012 to 2015 in order to evaluate tumor consistency changes after bromocriptine pretreatment and surgical outcomes.Methods We divided the patients into four groups;males in the dopamine agonist(DA) group,females in the DA group,males in the no DA group,and females in the no DA group,and we compared the surgery process,specimen Masson staining,and clinical outcomes of the four groups.According to a previously published classification,the operative notes from an experienced neurosurgeon were reviewed to classify the consistency of tumors as "fibrous" or "nonfibrous".Results No differences in tumor consistency were found in male patients with or without DA treatment.However,in female patients with DA treatment,tumors were likely to be harder in texture than the tumors of female patients without DA treatment.Despite tumor consistency differences between sexes,the tumor biological remission rate was similar between groups,as was the rate of tumor resection.Discussion Our study indicates that preoperative DA therapy impacts tumor consistency in female patients but not male patients.Although the surgical and histopathological outcomes are not influenced,these findings may provide useful information for the choice of operative approach and surgery process for pituitary adenoma.
文摘The grammar is an important part of English learning, but grammar learning has been a controversial topic in English learning profession, gone the process from worship to abandonment and then to a rational understanding. Firstly, this paper makes a brief introduction of the process, then introduces and discusses the significance, including sentence production, function of adjustment, fossilization solution, focusing on grammar phenomenon and grasping the components of language. Then, this paper presents two types of grammar, namely, tacit knowledge and explicit knowledge. Last, four approaches to obtain grammar ability are proposed.
基金supported by National Natural Science Foundation of China(Grant Nos.1110141411201453+1 种基金91130022 and 91130026)National Science Foundation of USA(Grant No.DMS 1207784)
文摘We consider the approximate acoustic cloaking in an inhomogeneous isotropic background space.By employing transformation media,together with the use of a sound-soft layer lining right outside the cloaked region,we show that one can achieve the near-invisibility by the"blow-up-a-small-region"construction.This is based on novel scattering estimates corresponding to multiple multi-scale obstacles located in an isotropic space.We develop a novel system of integral equations to decouple the nonlinear scattering interaction among the small obstacle components,the regular obstacle components and the inhomogeneous background medium.
基金supported by Vietnam National Foundation for Science and Technology Development(NAFOSTED)(Grant No.102.99-2013.06)
文摘Neural networks have been applied in various fields from signal processing, pattern recognition, associative memory to artifi- cial intelligence. Recently, nanoscale memristor has renewed interest in experimental realization of neural network. A neural network with a memristive synaptic weight is studied in this work. Dynamical properties of the proposed neural network are investigated through phase portraits, Poincar6 map, and Lyapunov exponents. Interestingly, the memristive neural network can generate hyperchaotic attractors without the presence of equilibrium points. Moreover, circuital implementation of such memristive neural network is presented to show its feasibility.
