The urban grass-roots library is an important part of the public cultural service system,and also a place to carry out national reading and lifelong learning,which is of great significance to the construction of a lea...The urban grass-roots library is an important part of the public cultural service system,and also a place to carry out national reading and lifelong learning,which is of great significance to the construction of a learning society.In this paper,the development and evolution of urban grassroots libraries in China are reviewed,and the current situation and usage issues of grassroots libraries in Beijing are analyzed.Moreover,the development strategy of idea stores in London,UK is studied,and characteristics are summarized,and possible references are sought.In the new era,urban grassroots libraries should integrate into communities with multiple functions and play a more sufficient role in public education,learning and training,and other aspects.展开更多
English grammar is at any time the important part of English learning,even if under the implementation of the New Course Standard.However,English grammar is considered to be difficult due to its complexity.My paper he...English grammar is at any time the important part of English learning,even if under the implementation of the New Course Standard.However,English grammar is considered to be difficult due to its complexity.My paper here is to explore and study the application of mathematic ideas and methods in English grammar teaching and learning,helping to facilitate the students to master the regularities,accuracy and systematization of English grammar,to improve learning efficiency,to enhance the learners' logic thinking,and at the same time,pointing out the specific strategies in practical use,which can be of great significance to the students' innovation and creativity and the students' development of the ability of cross-subject study advocated by both the Quality-Education and New Curriculum Standard.展开更多
Steeped in a civilization featuring inclusivity and peaceful nature,China seeks exchanges and mutual learning among civilizations rather than cultural hegemony.WHILE claiming its preeminent global economic status,Chin...Steeped in a civilization featuring inclusivity and peaceful nature,China seeks exchanges and mutual learning among civilizations rather than cultural hegemony.WHILE claiming its preeminent global economic status,China has also come to assert its equivalent position in world politics and diplomacy,typically representing the interests of the developing world.展开更多
Based on the implementation of the new college entrance examination reform policy and the demand of related policies,the choice of subjects for high school students has shifted from the traditional relatively single m...Based on the implementation of the new college entrance examination reform policy and the demand of related policies,the choice of subjects for high school students has shifted from the traditional relatively single model of arts and sciences division to the"3+3"model,and the topic of"how to infiltrate the concept of career education in the teaching process of senior high schools"has become increasingly important.However,at present,the implementation of career education in senior high schools is frequently limited,mainly in the form of class meetings,which instills the concept of career education to students.Therefore,the implementation effect is often not satisfactory.Therefore,experiential learning,a novel and efficient learning method,has entered public's view.Based on relevant research literature at home and abroad,we started with the importance and urgency of implementing career education in high schools,and generally reviewed the research status and future development trends of experiential career education both domestically and internationally.The practical and theoretical significance of the research were explained,and relevant concepts were summarized.Finally,strategic suggestions were proposed for integrating experiential career education concepts into biology teaching in ordinary high schools in China.展开更多
Air pollution has seriously endangered human health and the natural ecosystem during the last decades.Air quality monitoring stations(AQMS)have played a critical role in providing valuable data sets for recording regi...Air pollution has seriously endangered human health and the natural ecosystem during the last decades.Air quality monitoring stations(AQMS)have played a critical role in providing valuable data sets for recording regional air pollutants.The spatial representativeness of AQMS is a critical parameter when choosing the location of stations and assessing effects on the population to long-term exposure to air pollution.In this paper,we proposed a methodological framework for assessing the spatial representativeness of the regional air quality monitoring network and applied it to ground-based PM_(2.5)observation in the mainland of China.Weighted multidimensional Euclidean distance between each pixel and the stations was used to determine the representativeness of the existing monitoring network.In addition,the K-means clustering method was adopted to improve the spatial representativeness of the existing AQMS.The results showed that there were obvious differences among the representative area of 1820 stations in the mainland of China.The monitoring stations could well represent the PM_(2.5)spatial distribution of the entire region,and the effectively represented area(i.e.the area where the Euclidean distance between the pixels and the stations was lower than the average value)accounted for 67.32%of the total area and covered 93.12%of the population.Forty additional stations were identified in the Northwest,North China,and Northeast regions,which could improve the spatial representativeness by 14.31%.展开更多
The equation for determining cross-fault representative value is calculated based on hanging wall and foot wall reference level surfaces. The cross-fault data reliability are analyzed base on the stability of referenc...The equation for determining cross-fault representative value is calculated based on hanging wall and foot wall reference level surfaces. The cross-fault data reliability are analyzed base on the stability of reference datum and observation points, thereby facili- tating plotting of the representative value curves after removing interference. The spatial and temporal characteristics of fault deformation abnormalities before the 2016 Menyuan Ms6.4 earthquake, as well as the fault-movement characteristics reflected by representa- tive value, are summarized. The results show that many site trends had changed 1-3 years before the Menyuan Ms6.4 earthquake in the Qilian Fault, reflecting certain background abnormalities. The short-term abnormalities centrally had appeared in the 6 months to 1 year period before the earthquake near and in the neighborhood of the source region, demonstrating a significantly increased number of short-term abnormalities. Many sites near and in the neighborhood of the source region had strengthened inverse activities or had changed from positive to inverse activities in the most recent 2-3 years, which reflect stress-field enhancements or adjustment features.展开更多
The three-dimensional(3 D) structures of pores directly affect the CH4 flow.Therefore,it is very important to analyze the3 D spatial structure of pores and to simulate the CH4 flow with the connected pores as the carr...The three-dimensional(3 D) structures of pores directly affect the CH4 flow.Therefore,it is very important to analyze the3 D spatial structure of pores and to simulate the CH4 flow with the connected pores as the carrier.The result shows that the equivalent radius of pores and throats are 1-16 μm and 1.03-8.9 μm,respectively,and the throat length is 3.28-231.25 μm.The coordination number of pores concentrates around three,and the intersection point between the connectivity function and the X-axis is 3-4 μm,which indicate the macro-pores have good connectivity.During the single-channel flow,the pressure decreases along the direction of CH4 flow,and the flow velocity of CH4 decreases from the pore center to the wall.Under the dual-channel and the multi-channel flows,the pressure also decreases along the CH4 flow direction,while the velocity increases.The mean flow pressure gradually decreases with the increase of the distance from the inlet slice.The change of mean flow pressure is relatively stable in the direction horizontal to the bedding plane,while it is relatively large in the direction perpendicular to the bedding plane.The mean flow velocity in the direction horizontal to the bedding plane(Y-axis) is the largest,followed by that in the direction horizontal to the bedding plane(X-axis),and the mean flow velocity in the direction perpendicular to the bedding plane is the smallest.展开更多
Evolution of computational modeling and simulation has given more emphasis on the research activities related to carbon nanotube(CNT)reinforced polymer composites recently.This paper presents the composite cylinder as...Evolution of computational modeling and simulation has given more emphasis on the research activities related to carbon nanotube(CNT)reinforced polymer composites recently.This paper presents the composite cylinder assemblage(CCA)approach based on continuum mechanics for investigating the elastic properties of a polymer resin reinforced by multi-walled carbon nanotubes(MWCNTs).A three-phase cylindrical representative volume element(RVE)model is employed based on CCA technique to elucidate the effects of inter layers,chirality,interspacing,volume fraction of MWCNT,interphase properties and temperature conditions on the elastic modulus of the composite.The interface region between CNT and polymer matrix is modeled as the third phase with varying material properties.The constitutive relations for each material system have been derived based on solid mechanics and proper interfacial traction continuity conditions are imposed.The predicted results from the CCA approach are in well agreement with RVE-based finite element model.The outcomes reveal that temperature softening effect becomes more pronounced at higher volume fractions of CNTs.展开更多
This paper proposes an original behavioural finance representative agent model,to explain how fake news’empirical price impacts can persist in finance despite contradicting the efficient-market hypothesis.The model r...This paper proposes an original behavioural finance representative agent model,to explain how fake news’empirical price impacts can persist in finance despite contradicting the efficient-market hypothesis.The model reconciles empirically-observed price overreactions to fake news with empirically-observed price underreactions to real news,and predicts a novel secondary impact of fake news:that fake news in a security amplifies underreactions to subsequent real news for the security.Evaluating the model against a large-sample event study of the 2019 Chinese ADR Delisting Threat fake news and debunking event,this paper finds strong qualitative validation for its model’s dynamics and predictions.展开更多
According to Kirillov's idea, the irreducible unitary representations of a Lie group G roughly correspond to the coadjoint orbits (?).In the forward direction one applies the methods of geometric quantization to p...According to Kirillov's idea, the irreducible unitary representations of a Lie group G roughly correspond to the coadjoint orbits (?).In the forward direction one applies the methods of geometric quantization to produce a representation, and in the reverse direction one computes a transform of the character of a representation, to obtain a coadjoint orbit. The method of orbits in the representations of Lie groups suggests the detailed study of coadjoint orbits of a Lie group G in the space (?)~* dual to the Lie algebra (?) of G. In this paper, two primary goals are achieved: one is to completely classify the smooth coadjoint orbits of Virasoro group for nonzero central charge c; the other is to find representatives for coadjoint orbits. These questions have been considered previously by Segal, Kirillov, and Witten, but their results are not quite complete. To accomplish this, the authors start by describing the coadjoint action of D-the Lie group of all orientation preserving diffeomorphisms on the circle S^1, and its central extension (?), then the authors will give a complete classification of smooth coadjoint orbits. In fact, they can be parameterized by a subspace Of conjugacy classes of (?)(1,1). Finally, the authors will show how to find representatives f coadjoint orbits by analyzing the vector fields stabilizing the orbits, and describe the amazing connection between the characteristic (trace) of conjugacy classes of (?)(1, 1) and that of vector fields stabilizing orbits.展开更多
A novel diagrammtic method is proposed to show the angular distribution of bases of human protein sequences. Using this method, the distribution sphere[1-4] is divided into four regions with same volume. The picture i...A novel diagrammtic method is proposed to show the angular distribution of bases of human protein sequences. Using this method, the distribution sphere[1-4] is divided into four regions with same volume. The picture is clearer and more intuitive than that in [1] .A rule on the angular distribution of the representative points of bases of protein sequences is given. Besides, in 300 representative pointS of human protein sequence samples we find that there are three (not only one) points outside the sphere.展开更多
Purpose: The main goal of this study is to provide reliable comparison of performance in higher education. In this respect, we use scientometric measures associated with faculties of medicine in the six health studie...Purpose: The main goal of this study is to provide reliable comparison of performance in higher education. In this respect, we use scientometric measures associated with faculties of medicine in the six health studies universities in Romania.Design/methodology/approach: The method to estimate the minimum necessary size, proposed in in Shen et al.(2017), is applied in this article. We collected data from the Scopus data-base for the academics of the departments of medicine within the six health studies universities in Romania during the 2009 to 2014. And two kind of statistic treatments based on that method are implemented, pair-wise comparison and one-to-the-rest comparison. All the results of these comparisons are shown.Findings: According to the results: We deem that Cluj and Tg. Mure? have the superior and inferior performance respectively, since their reasonably small value of the minimum representative size, in either of the kinds of comparison, whichever indexes of citations, h-index, or g-index is used. we can not reliably distinguish differences among the rest of the faculties, since the quite large value of their minimum representative size.Research limitations: There is only six faculties of medicine in health studies universities in Romania are analyzed.Practical implications: Our methods of comparison play an important role in ranking data sets associated with different collective units, such as faculties, universities, institutions, based on some aggregate scores like mean and totality. Originality/value: We applied the minimum representative size to a new emprical context- that of the departments of medicine in the health studies universities in Romania.展开更多
The research examines the way in which members of the U.S. House of Representative represent themselves on the social network site Facebook. Each member’s activity is observed on seven different occasions and the fre...The research examines the way in which members of the U.S. House of Representative represent themselves on the social network site Facebook. Each member’s activity is observed on seven different occasions and the frequency and substantive character of posts made during the second half of 2013 are established. The focus is on position-taking posts versus posts which mention the district the member serves in. Our expectation is that members from electorally safe districts will be more likely to advertise their policy positions while members from marginal districts will be more inclined to advertise their district connections. We control for minority party status, gender, and ideological extremism among other concerns and learn electoral safety is a good predictor of both “position-taking” and “district mentions”. Consistent with an electoral motive, we also find members from the minority party less likely to take positions on the issues of the day and more likely to mention the district they serve in.展开更多
Ideas from engineering have helped the understanding of biological organisms for thousands of years. However, the mechanical aspects of biological materials and structures can, if properly interpreted and analysed, le...Ideas from engineering have helped the understanding of biological organisms for thousands of years. However, the mechanical aspects of biological materials and structures can, if properly interpreted and analysed, lead to a deeper understanding of the biology of organisms. Such an approach, although always current in some form, is nevertheless subject to the vagaries of fashion and the availability of analytical techniques. At present we are in a period of upturn. Areas of interest are deployable structures (applications in aerospace), palaeontology (how little do we need to know in order to create a credible biosphere) and food science (we need a rational approach to the mechanics of food).展开更多
In the world literature,there are many valuable ecological ideas.Nowadays,a growing number of writers in the world literature have begun to pay attention to ecological problems.They use their writings to reflect the s...In the world literature,there are many valuable ecological ideas.Nowadays,a growing number of writers in the world literature have begun to pay attention to ecological problems.They use their writings to reflect the severe ecological problems,to express their ecological thoughts,and also to alert readers.In the world literature,we can dig out many philosophical ideas,including the interdependence of man and nature,the reconstruction of the harmonious relationship between man and animal as well as the phenomenon of"spiritual imbalance"in social life.Analyzing these ideas will not only help us understand the creative connotations of the writers,but also provide helpful suggestions to solve real ecological problems.展开更多
Diamond, cubic boron nitride(c-BN), silicon(Si), and germanium(Ge), as examples of typical strong covalent materials, have been extensively investigated in recent decades, owing to their fundamental importance in mate...Diamond, cubic boron nitride(c-BN), silicon(Si), and germanium(Ge), as examples of typical strong covalent materials, have been extensively investigated in recent decades, owing to their fundamental importance in material science and industry. However, an in-depth analysis of the character of these materials' mechanical behaviors under harsh service environments, such as high pressure, has yet to be conducted. Based on several mechanical criteria, the effect of pressure on the mechanical properties of these materials is comprehensively investigated.It is demonstrated that, with respect to their intrinsic brittleness/ductile nature, all these materials exhibit ubiquitous pressure-enhanced ductility. By analyzing the strength variation under uniform deformation, together with the corresponding electronic structures, we reveal for the first time that the pressure-induced mechanical softening/weakening exhibits distinct characteristics between diamond and c-BN, owing to the differences in their abnormal charge-depletion evolution under applied strain, whereas a monotonous weakening phenomenon is observed in Si and Ge. Further investigation into dislocation-mediated plastic resistance indicates that the pressure-induced shuffle-set plane softening in diamond(c-BN), and weakening in Si(Ge), can be attributed to the reduction of antibonding states below the Fermi level, and an enhanced metallization, corresponding to the weakening of the bonds around the slipped plane with increasing pressure, respectively. These findings not only reveal the physical mechanism of pressure-induced softening/weakening in covalent materials, but also highlights the necessity of exploring strain-tunable electronic structures to emphasize the mechanical response in such covalent materials.展开更多
Ernest Hemingway is hailed by many critics as a great craftsman,and “the most important,outstanding author since the death of Shakespeare”. On the other hand,he is severely criticized by critics who doggedly insist ...Ernest Hemingway is hailed by many critics as a great craftsman,and “the most important,outstanding author since the death of Shakespeare”. On the other hand,he is severely criticized by critics who doggedly insist that Hemingway is too limited,his theme is too narrow,and,his characters are mute,insensitive and uncomplicated man.However,a very important aspect in the evaluation of Hemingway seems to have been overlooked both by those who devoutly adore him and those who strongly disparage him. This thesis therefore proposes to take a new perspective in exploring Hemingways writing in the hope of exposing his existentialist ideas-consisting of “the absurd world”,“nada of life”,and “choice and code.”-as expressed in both his major and his minor work.展开更多
This paper suggests a hydrodynamic stability theory of distorted laminar flow, and presents a kind of distortion profile of mean velocity in parallel shear flow. With such distortion profiles, the new theory can be us...This paper suggests a hydrodynamic stability theory of distorted laminar flow, and presents a kind of distortion profile of mean velocity in parallel shear flow. With such distortion profiles, the new theory can be used to investigate the stability behaviour of parallel shear flow, and thus suggests a new possible approach to instability.展开更多
On the basis of survey of current situations of eco-agricultural construction in Gongcheng County, major "Cultivation + Methane + Planting" triple model of ecological agriculture in Gongcheng County is prese...On the basis of survey of current situations of eco-agricultural construction in Gongcheng County, major "Cultivation + Methane + Planting" triple model of ecological agriculture in Gongcheng County is presented. Then, the eco-agricultural benefits of Gongcheng County are analyzed from three aspects, namely economic, social and ecological benefits. Through summing up, the eco-agricultural construction of Gongcheng County has following problems: imperfect ecological technological system; follow-up service level and ability to be improved; slow in unified planning and design and industrialization step. Finally, ideas of further development of ecological agriculture in Gongcheng County are put forward. These include proper planning and overall management, extending ideas and deepening eco-agricultural construction system; strengthening development of ecological tourism; and perfecting social service system for ecological agriculture.展开更多
基金the National Natural Science Foundation of China(51708001).
文摘The urban grass-roots library is an important part of the public cultural service system,and also a place to carry out national reading and lifelong learning,which is of great significance to the construction of a learning society.In this paper,the development and evolution of urban grassroots libraries in China are reviewed,and the current situation and usage issues of grassroots libraries in Beijing are analyzed.Moreover,the development strategy of idea stores in London,UK is studied,and characteristics are summarized,and possible references are sought.In the new era,urban grassroots libraries should integrate into communities with multiple functions and play a more sufficient role in public education,learning and training,and other aspects.
文摘English grammar is at any time the important part of English learning,even if under the implementation of the New Course Standard.However,English grammar is considered to be difficult due to its complexity.My paper here is to explore and study the application of mathematic ideas and methods in English grammar teaching and learning,helping to facilitate the students to master the regularities,accuracy and systematization of English grammar,to improve learning efficiency,to enhance the learners' logic thinking,and at the same time,pointing out the specific strategies in practical use,which can be of great significance to the students' innovation and creativity and the students' development of the ability of cross-subject study advocated by both the Quality-Education and New Curriculum Standard.
文摘Steeped in a civilization featuring inclusivity and peaceful nature,China seeks exchanges and mutual learning among civilizations rather than cultural hegemony.WHILE claiming its preeminent global economic status,China has also come to assert its equivalent position in world politics and diplomacy,typically representing the interests of the developing world.
文摘Based on the implementation of the new college entrance examination reform policy and the demand of related policies,the choice of subjects for high school students has shifted from the traditional relatively single model of arts and sciences division to the"3+3"model,and the topic of"how to infiltrate the concept of career education in the teaching process of senior high schools"has become increasingly important.However,at present,the implementation of career education in senior high schools is frequently limited,mainly in the form of class meetings,which instills the concept of career education to students.Therefore,the implementation effect is often not satisfactory.Therefore,experiential learning,a novel and efficient learning method,has entered public's view.Based on relevant research literature at home and abroad,we started with the importance and urgency of implementing career education in high schools,and generally reviewed the research status and future development trends of experiential career education both domestically and internationally.The practical and theoretical significance of the research were explained,and relevant concepts were summarized.Finally,strategic suggestions were proposed for integrating experiential career education concepts into biology teaching in ordinary high schools in China.
基金funded by the National Natural Science Foundation of China (41977399)the National Key Research and Development Program (2017YFC0505800)
文摘Air pollution has seriously endangered human health and the natural ecosystem during the last decades.Air quality monitoring stations(AQMS)have played a critical role in providing valuable data sets for recording regional air pollutants.The spatial representativeness of AQMS is a critical parameter when choosing the location of stations and assessing effects on the population to long-term exposure to air pollution.In this paper,we proposed a methodological framework for assessing the spatial representativeness of the regional air quality monitoring network and applied it to ground-based PM_(2.5)observation in the mainland of China.Weighted multidimensional Euclidean distance between each pixel and the stations was used to determine the representativeness of the existing monitoring network.In addition,the K-means clustering method was adopted to improve the spatial representativeness of the existing AQMS.The results showed that there were obvious differences among the representative area of 1820 stations in the mainland of China.The monitoring stations could well represent the PM_(2.5)spatial distribution of the entire region,and the effectively represented area(i.e.the area where the Euclidean distance between the pixels and the stations was lower than the average value)accounted for 67.32%of the total area and covered 93.12%of the population.Forty additional stations were identified in the Northwest,North China,and Northeast regions,which could improve the spatial representativeness by 14.31%.
基金supported by the Seismic Regime Tracking Project in the Year of 2016,China Earthquake Administration(2016010205 and 2016020204)
文摘The equation for determining cross-fault representative value is calculated based on hanging wall and foot wall reference level surfaces. The cross-fault data reliability are analyzed base on the stability of reference datum and observation points, thereby facili- tating plotting of the representative value curves after removing interference. The spatial and temporal characteristics of fault deformation abnormalities before the 2016 Menyuan Ms6.4 earthquake, as well as the fault-movement characteristics reflected by representa- tive value, are summarized. The results show that many site trends had changed 1-3 years before the Menyuan Ms6.4 earthquake in the Qilian Fault, reflecting certain background abnormalities. The short-term abnormalities centrally had appeared in the 6 months to 1 year period before the earthquake near and in the neighborhood of the source region, demonstrating a significantly increased number of short-term abnormalities. Many sites near and in the neighborhood of the source region had strengthened inverse activities or had changed from positive to inverse activities in the most recent 2-3 years, which reflect stress-field enhancements or adjustment features.
基金financially supported by the National Key Research and Development Plan(No.2018YFB0605601)the National Natural Science Foundation of China(No.41972168)。
文摘The three-dimensional(3 D) structures of pores directly affect the CH4 flow.Therefore,it is very important to analyze the3 D spatial structure of pores and to simulate the CH4 flow with the connected pores as the carrier.The result shows that the equivalent radius of pores and throats are 1-16 μm and 1.03-8.9 μm,respectively,and the throat length is 3.28-231.25 μm.The coordination number of pores concentrates around three,and the intersection point between the connectivity function and the X-axis is 3-4 μm,which indicate the macro-pores have good connectivity.During the single-channel flow,the pressure decreases along the direction of CH4 flow,and the flow velocity of CH4 decreases from the pore center to the wall.Under the dual-channel and the multi-channel flows,the pressure also decreases along the CH4 flow direction,while the velocity increases.The mean flow pressure gradually decreases with the increase of the distance from the inlet slice.The change of mean flow pressure is relatively stable in the direction horizontal to the bedding plane,while it is relatively large in the direction perpendicular to the bedding plane.The mean flow velocity in the direction horizontal to the bedding plane(Y-axis) is the largest,followed by that in the direction horizontal to the bedding plane(X-axis),and the mean flow velocity in the direction perpendicular to the bedding plane is the smallest.
文摘Evolution of computational modeling and simulation has given more emphasis on the research activities related to carbon nanotube(CNT)reinforced polymer composites recently.This paper presents the composite cylinder assemblage(CCA)approach based on continuum mechanics for investigating the elastic properties of a polymer resin reinforced by multi-walled carbon nanotubes(MWCNTs).A three-phase cylindrical representative volume element(RVE)model is employed based on CCA technique to elucidate the effects of inter layers,chirality,interspacing,volume fraction of MWCNT,interphase properties and temperature conditions on the elastic modulus of the composite.The interface region between CNT and polymer matrix is modeled as the third phase with varying material properties.The constitutive relations for each material system have been derived based on solid mechanics and proper interfacial traction continuity conditions are imposed.The predicted results from the CCA approach are in well agreement with RVE-based finite element model.The outcomes reveal that temperature softening effect becomes more pronounced at higher volume fractions of CNTs.
文摘This paper proposes an original behavioural finance representative agent model,to explain how fake news’empirical price impacts can persist in finance despite contradicting the efficient-market hypothesis.The model reconciles empirically-observed price overreactions to fake news with empirically-observed price underreactions to real news,and predicts a novel secondary impact of fake news:that fake news in a security amplifies underreactions to subsequent real news for the security.Evaluating the model against a large-sample event study of the 2019 Chinese ADR Delisting Threat fake news and debunking event,this paper finds strong qualitative validation for its model’s dynamics and predictions.
文摘According to Kirillov's idea, the irreducible unitary representations of a Lie group G roughly correspond to the coadjoint orbits (?).In the forward direction one applies the methods of geometric quantization to produce a representation, and in the reverse direction one computes a transform of the character of a representation, to obtain a coadjoint orbit. The method of orbits in the representations of Lie groups suggests the detailed study of coadjoint orbits of a Lie group G in the space (?)~* dual to the Lie algebra (?) of G. In this paper, two primary goals are achieved: one is to completely classify the smooth coadjoint orbits of Virasoro group for nonzero central charge c; the other is to find representatives for coadjoint orbits. These questions have been considered previously by Segal, Kirillov, and Witten, but their results are not quite complete. To accomplish this, the authors start by describing the coadjoint action of D-the Lie group of all orientation preserving diffeomorphisms on the circle S^1, and its central extension (?), then the authors will give a complete classification of smooth coadjoint orbits. In fact, they can be parameterized by a subspace Of conjugacy classes of (?)(1,1). Finally, the authors will show how to find representatives f coadjoint orbits by analyzing the vector fields stabilizing the orbits, and describe the amazing connection between the characteristic (trace) of conjugacy classes of (?)(1, 1) and that of vector fields stabilizing orbits.
文摘A novel diagrammtic method is proposed to show the angular distribution of bases of human protein sequences. Using this method, the distribution sphere[1-4] is divided into four regions with same volume. The picture is clearer and more intuitive than that in [1] .A rule on the angular distribution of the representative points of bases of protein sequences is given. Besides, in 300 representative pointS of human protein sequence samples we find that there are three (not only one) points outside the sphere.
文摘Purpose: The main goal of this study is to provide reliable comparison of performance in higher education. In this respect, we use scientometric measures associated with faculties of medicine in the six health studies universities in Romania.Design/methodology/approach: The method to estimate the minimum necessary size, proposed in in Shen et al.(2017), is applied in this article. We collected data from the Scopus data-base for the academics of the departments of medicine within the six health studies universities in Romania during the 2009 to 2014. And two kind of statistic treatments based on that method are implemented, pair-wise comparison and one-to-the-rest comparison. All the results of these comparisons are shown.Findings: According to the results: We deem that Cluj and Tg. Mure? have the superior and inferior performance respectively, since their reasonably small value of the minimum representative size, in either of the kinds of comparison, whichever indexes of citations, h-index, or g-index is used. we can not reliably distinguish differences among the rest of the faculties, since the quite large value of their minimum representative size.Research limitations: There is only six faculties of medicine in health studies universities in Romania are analyzed.Practical implications: Our methods of comparison play an important role in ranking data sets associated with different collective units, such as faculties, universities, institutions, based on some aggregate scores like mean and totality. Originality/value: We applied the minimum representative size to a new emprical context- that of the departments of medicine in the health studies universities in Romania.
文摘The research examines the way in which members of the U.S. House of Representative represent themselves on the social network site Facebook. Each member’s activity is observed on seven different occasions and the frequency and substantive character of posts made during the second half of 2013 are established. The focus is on position-taking posts versus posts which mention the district the member serves in. Our expectation is that members from electorally safe districts will be more likely to advertise their policy positions while members from marginal districts will be more inclined to advertise their district connections. We control for minority party status, gender, and ideological extremism among other concerns and learn electoral safety is a good predictor of both “position-taking” and “district mentions”. Consistent with an electoral motive, we also find members from the minority party less likely to take positions on the issues of the day and more likely to mention the district they serve in.
文摘Ideas from engineering have helped the understanding of biological organisms for thousands of years. However, the mechanical aspects of biological materials and structures can, if properly interpreted and analysed, lead to a deeper understanding of the biology of organisms. Such an approach, although always current in some form, is nevertheless subject to the vagaries of fashion and the availability of analytical techniques. At present we are in a period of upturn. Areas of interest are deployable structures (applications in aerospace), palaeontology (how little do we need to know in order to create a credible biosphere) and food science (we need a rational approach to the mechanics of food).
基金supported by Anhui Province Excellent Young Talents Support Program(Grant No.gxyq2019180).
文摘In the world literature,there are many valuable ecological ideas.Nowadays,a growing number of writers in the world literature have begun to pay attention to ecological problems.They use their writings to reflect the severe ecological problems,to express their ecological thoughts,and also to alert readers.In the world literature,we can dig out many philosophical ideas,including the interdependence of man and nature,the reconstruction of the harmonious relationship between man and animal as well as the phenomenon of"spiritual imbalance"in social life.Analyzing these ideas will not only help us understand the creative connotations of the writers,but also provide helpful suggestions to solve real ecological problems.
基金Supported by the National Natural Science Foundation of China (Grant No.51672015)the National Key Research and Development Program of China (Grant Nos.2016YFC1102500 and 2017YFB0702100)+3 种基金the 111 Project (Grant No.B17002)and the Fundamental Research Funds for the Central Universitiessupported by the European Regional Development Fund in the IT4Innovations National Supercomputing Center—Path to Exascale Project (Grant No.CZ.02.1.01/0.0/0.0/16 013/0001791)within the Operational Programme for Research,Development and Education,and by the Large Infrastructures for Research,Experimental Development,and Innovation Project (Grant No.e-INFRA CZ-LM2018140) by the Ministry of Education,Youth,Sport of the Czech Republic。
文摘Diamond, cubic boron nitride(c-BN), silicon(Si), and germanium(Ge), as examples of typical strong covalent materials, have been extensively investigated in recent decades, owing to their fundamental importance in material science and industry. However, an in-depth analysis of the character of these materials' mechanical behaviors under harsh service environments, such as high pressure, has yet to be conducted. Based on several mechanical criteria, the effect of pressure on the mechanical properties of these materials is comprehensively investigated.It is demonstrated that, with respect to their intrinsic brittleness/ductile nature, all these materials exhibit ubiquitous pressure-enhanced ductility. By analyzing the strength variation under uniform deformation, together with the corresponding electronic structures, we reveal for the first time that the pressure-induced mechanical softening/weakening exhibits distinct characteristics between diamond and c-BN, owing to the differences in their abnormal charge-depletion evolution under applied strain, whereas a monotonous weakening phenomenon is observed in Si and Ge. Further investigation into dislocation-mediated plastic resistance indicates that the pressure-induced shuffle-set plane softening in diamond(c-BN), and weakening in Si(Ge), can be attributed to the reduction of antibonding states below the Fermi level, and an enhanced metallization, corresponding to the weakening of the bonds around the slipped plane with increasing pressure, respectively. These findings not only reveal the physical mechanism of pressure-induced softening/weakening in covalent materials, but also highlights the necessity of exploring strain-tunable electronic structures to emphasize the mechanical response in such covalent materials.
文摘Ernest Hemingway is hailed by many critics as a great craftsman,and “the most important,outstanding author since the death of Shakespeare”. On the other hand,he is severely criticized by critics who doggedly insist that Hemingway is too limited,his theme is too narrow,and,his characters are mute,insensitive and uncomplicated man.However,a very important aspect in the evaluation of Hemingway seems to have been overlooked both by those who devoutly adore him and those who strongly disparage him. This thesis therefore proposes to take a new perspective in exploring Hemingways writing in the hope of exposing his existentialist ideas-consisting of “the absurd world”,“nada of life”,and “choice and code.”-as expressed in both his major and his minor work.
基金Project Supported by National Natural Science Foundation of China
文摘This paper suggests a hydrodynamic stability theory of distorted laminar flow, and presents a kind of distortion profile of mean velocity in parallel shear flow. With such distortion profiles, the new theory can be used to investigate the stability behaviour of parallel shear flow, and thus suggests a new possible approach to instability.
基金Supported by Scientific Research Foundation for Leaders of Disciplines in Guangxi Vocational and Technical College of Agriculture(Grant No: [2011]13)
文摘On the basis of survey of current situations of eco-agricultural construction in Gongcheng County, major "Cultivation + Methane + Planting" triple model of ecological agriculture in Gongcheng County is presented. Then, the eco-agricultural benefits of Gongcheng County are analyzed from three aspects, namely economic, social and ecological benefits. Through summing up, the eco-agricultural construction of Gongcheng County has following problems: imperfect ecological technological system; follow-up service level and ability to be improved; slow in unified planning and design and industrialization step. Finally, ideas of further development of ecological agriculture in Gongcheng County are put forward. These include proper planning and overall management, extending ideas and deepening eco-agricultural construction system; strengthening development of ecological tourism; and perfecting social service system for ecological agriculture.