Due to the rapid growth of the economy and society,the burden of social security has been increasingly escalating,resulting in a continuous rise in parenting stress among certain groups of parents.On one hand,these pa...Due to the rapid growth of the economy and society,the burden of social security has been increasingly escalating,resulting in a continuous rise in parenting stress among certain groups of parents.On one hand,these parents aspire for their young children to grow through play;on the other hand,they are acutely aware that early childhood education constitutes the foundational stage of basic education and serves as the commencement phase of lifelong learning.Thus,they recognize the importance of emphasizing early childhood education.Therefore,preschool education has been given important significance.Parents place particular emphasis on education during this stage.They actively leverage their educational,financial,and social advantages to create favorable educational resources and opportunities for their young children.However,to a certain extent,this exacerbates educational anxiety among a segment of parents.Despite the implementation of various governmental measures,it appears that these initiatives have not fundamentally addressed parental educational anxiety at its root.This study employs interview techniques and literature review methodologies to gain a profound understanding of parental educational anxiety during the transition from early childhood to primary education.By integrating Gesell's Maturation Theory,this research aims to scientifically explicate the developmental patterns of children.Consequently,it endeavors to enable non-professional parents to adopt a"professional"perspective in their approach towards early childhood education.展开更多
Marx’s theory of natural forces is an indispensable part of Marx’s economic theory.As a natural element that does not need to spend a penny,natural forces are added to the production process free of charge,and play ...Marx’s theory of natural forces is an indispensable part of Marx’s economic theory.As a natural element that does not need to spend a penny,natural forces are added to the production process free of charge,and play a special restrictive role in the production process.Mastering and applying the scientific connotation of Marx’s theory has very important theoretical value and practical significance for adhering to the sustainable development of nature,economy and society.展开更多
The cleavage force F(z) needed to separate parallel atomic planes by a distance z is first discussed for simple s-p metals using density functional theory.For the s-p nearly free-electron metals the linearized Thomas-...The cleavage force F(z) needed to separate parallel atomic planes by a distance z is first discussed for simple s-p metals using density functional theory.For the s-p nearly free-electron metals the linearized Thomas-Fermi equation is solved self-consistently in the cases of (a) semi-infinite planes of jellium (i.e. smeared uniform positive ions) and (b) a semi-infinite cylinder of finite radius, cleaved by a plane perpendicular to its axis. In (a), the elastic region has the form F(z)=Az ∝ Zrs-11/2, where rs is the mean interelectronic distance in the jellium model. Size effects are then considered, with possible relevance to atomic force microscopy.Defect energies are treated, using both electron theory and pair force laws.展开更多
As a basic principle in classical mechanics,the Galilean invariance states that the force is the same in all inertial frames of reference.But this principle has not been properly addressed by most unsteady aerodynamic...As a basic principle in classical mechanics,the Galilean invariance states that the force is the same in all inertial frames of reference.But this principle has not been properly addressed by most unsteady aerodynamic force theories,if the partial force contributed by a local flow structure is to be evaluated.In this note,we discuss the Galilean-invariance conditions of the partial force for several typical theories and numerically test what would happen if these conditions do not hold.展开更多
The effects of the interactions between bi-directional pedestrians on the crossing time and the crosswalk width are studied. Firstly,the crossing process of bi-directional pedestrians is analyzed.The total crosswalk t...The effects of the interactions between bi-directional pedestrians on the crossing time and the crosswalk width are studied. Firstly,the crossing process of bi-directional pedestrians is analyzed.The total crosswalk time is divided into a discharge time and a crossing time. The interactions between bi-directional pedestrians are quantified with the drag force theory. Then,a model is developed to study the crossing time based on the kinetic energy theory and momentum theory. Subsequently,the related parameters of the proposed model are calibrated with observed information. The relationships among crosswalk width,signal time,pedestrian volume and level of service are simulated with the proposed model. The results are verified and compared with other models. The proposed model has an absolute value of relative error of 9. 38%,which is smaller than that of the Alhajyaseen model( 15. 26%) and Highway Capacity Manual( HCM) model( 12. 42%). Finally,suggested crosswalk widths at different conditions are successfully estimated with the proposed crossing time model.展开更多
With the rapid development of globalization, the whole world interweaves unprecedentedly. The frequent global communication is in desperate need of qualified translators and interpreters which draws great attention an...With the rapid development of globalization, the whole world interweaves unprecedentedly. The frequent global communication is in desperate need of qualified translators and interpreters which draws great attention and invokes discussion about the standard of translation. Is the widely acknowledged criterion—neutral position a possible and necessary regulation to justify professional translators? This essay will illustrate that the interpreters influenced by environment, culture and other factors can’t perform with an absolute neutral position. Furthermore, the creativity of interpreters, who conduct heuristic work instead of algorithmic and reduplicated work, play a pivotal role in qualified work and their long-term development on the basis of Skopos Theory and classical examples, which testifies that it is improper to regard neutral position as a significant standard to evaluate the quality of interpreters.展开更多
The study contains the justification of J.M. Herndon’s thesis about the existence of a thermonuclear reactor in the Earth’s core. A scenario of the formation of a spontaneous nuclear reactor is presented, referring ...The study contains the justification of J.M. Herndon’s thesis about the existence of a thermonuclear reactor in the Earth’s core. A scenario of the formation of a spontaneous nuclear reactor is presented, referring to the universal law of gravity, to the relationship between matter and energy, and to the properties of plasma. The theoretical attitudes of the discussed phenomena and the relations between them can be called the Theory of the Primordial Forces of Nature. It includes the interactions of the gravitational field, the forces of the electromagnetic field, which determine the properties of matter, and the strong interactions resulting from the release of nuclear energy. Arguments for the thesis about the commonness of the phenomenon of thermonuclear reactors in space are presented. The second part of the article presents examples of geological phenomena that confirm the activity of a thermonuclear reactor in the center of the Earth.展开更多
A new analytical expression for calculating the wave force on a composite bucket foundation is obtained. Based on the diffraction theory, the analytical solution of the wave pressure and the wave force on the composit...A new analytical expression for calculating the wave force on a composite bucket foundation is obtained. Based on the diffraction theory, the analytical solution of the wave pressure and the wave force on the composite bucket foundation is accurately derived by assigning reasonable boundary conditions. Experiments for the wave pressure on the bucket foundation with a scale of 1:60 under different wave conditions in the wave flume are designed and conducted. The analytical results agree well with the experimental data, and the theoretical approach can accurately predict the wave force on the large-scale structures. The wave pressure distribution on the composite bucket foundation is presented and the influence of the wave height, the water depth and the wave period on the wave force on the composite bucket foundation is investigated. This study provides a quite accurate method to calculate the wave force on a composite bucket foundation, which gives a good framework for future studies of the wave force on other large-scale structures with complex boundaries.展开更多
Magnetotactic Bacteria (MTB) propel themselves by rotating their flagella and swim along the magnetic field lines. To analyze the motion of MTB, MTB magneto-ovoid strain MO-1 cells, each with two bundles of flagella...Magnetotactic Bacteria (MTB) propel themselves by rotating their flagella and swim along the magnetic field lines. To analyze the motion of MTB, MTB magneto-ovoid strain MO-1 cells, each with two bundles of flagella, were taken as research object. The six-degrees-of-freedom (6-DoF) dynamic model of MO-1 was established based on the Newton-Euler dynamic equations. In particular, the interaction between the flagellum and fluid was considered by the resistive force theory. The simulated motion trajectory of MTB was found to consist of two kinds of helices: small helices restilting from the imbalance of force due to flagellar rotation, and large helices arising from the different directions of the rotation axis of the cell body and the propulsion axis of the flagellum. The motion behaviours of MTB in various magnetic fields were studied, and the simulation results agree well with the experiment results. In addition, the rotation frequency of the flagella was estimated at 1100 Hz, which is consistent with the average rotation rate for Na^+-driven flagellar motors. The included angle of the magnetosome chain was predicted at 40° that is located within 20° to 60° range of the observed results. The results indicate the correctness of the dynamic model, which may aid research on the operation and control of MTB-propelled micro-actuators. Meanwhile, the motion behaviours of MTB may inspire the development of micro-robots with new driving mechanisms.展开更多
The Hayabusa2 asteroid explorer mission focuses principally on the touchdown and sampling on near-Earth asteroid 162173 Ryugu.Hayabusa2 successfully landed on its surface and ejected a projectile for sample collection...The Hayabusa2 asteroid explorer mission focuses principally on the touchdown and sampling on near-Earth asteroid 162173 Ryugu.Hayabusa2 successfully landed on its surface and ejected a projectile for sample collection on February 22,2019.Hayabusa2 later landed near a crater formed by an impactor and executed the sampling sequence again on July 11,2019.For a successful mission,a thorough understanding and evaluation of spacecraft dynamics during touchdown were crucial.The most challenging aspect of this study was the modeling of such spacecraft phenomena as the dynamics of landing on a surface with unknown properties.In particular,a Monte Carlo analysis was used to determine the parameters of the operational design for the final descent and touchdown sequence.This paper discusses the dynamical modeling of the simulation during the touchdown of Hayabusa2.展开更多
Si dangling bonds at the interface of quasi-free-standing monolayer graphene (QFMLG) are known to act as scattering centers that can severely affect carrier mobility Herein, we investigate the atomic and electronic ...Si dangling bonds at the interface of quasi-free-standing monolayer graphene (QFMLG) are known to act as scattering centers that can severely affect carrier mobility Herein, we investigate the atomic and electronic structure of Si dangling bonds in QFMLG using low-temperature scanning tunneling microscopy/ spectroscopy (STM/STS), atomic force microscopy (AFM), and density functional theory (DFT) calculations. Two types of defects with different contrast were observed on a flat graphene terrace by STM and AFM; in particular, their STM contrast varied with the bias voltage. Moreover, these defects showed characteristic STS peaks at different energies, 1.1 and 1.4 eV. The comparison of the experimental data with the DFT calculations indicates that the defects with STS peak energies of 1.1 and 1.4 eV consist of clusters of three and four Si dangling bonds, respectively. The relevance of the present results for the optimization of graphene synthesis is discussed.展开更多
文摘Due to the rapid growth of the economy and society,the burden of social security has been increasingly escalating,resulting in a continuous rise in parenting stress among certain groups of parents.On one hand,these parents aspire for their young children to grow through play;on the other hand,they are acutely aware that early childhood education constitutes the foundational stage of basic education and serves as the commencement phase of lifelong learning.Thus,they recognize the importance of emphasizing early childhood education.Therefore,preschool education has been given important significance.Parents place particular emphasis on education during this stage.They actively leverage their educational,financial,and social advantages to create favorable educational resources and opportunities for their young children.However,to a certain extent,this exacerbates educational anxiety among a segment of parents.Despite the implementation of various governmental measures,it appears that these initiatives have not fundamentally addressed parental educational anxiety at its root.This study employs interview techniques and literature review methodologies to gain a profound understanding of parental educational anxiety during the transition from early childhood to primary education.By integrating Gesell's Maturation Theory,this research aims to scientifically explicate the developmental patterns of children.Consequently,it endeavors to enable non-professional parents to adopt a"professional"perspective in their approach towards early childhood education.
文摘Marx’s theory of natural forces is an indispensable part of Marx’s economic theory.As a natural element that does not need to spend a penny,natural forces are added to the production process free of charge,and play a special restrictive role in the production process.Mastering and applying the scientific connotation of Marx’s theory has very important theoretical value and practical significance for adhering to the sustainable development of nature,economy and society.
文摘The cleavage force F(z) needed to separate parallel atomic planes by a distance z is first discussed for simple s-p metals using density functional theory.For the s-p nearly free-electron metals the linearized Thomas-Fermi equation is solved self-consistently in the cases of (a) semi-infinite planes of jellium (i.e. smeared uniform positive ions) and (b) a semi-infinite cylinder of finite radius, cleaved by a plane perpendicular to its axis. In (a), the elastic region has the form F(z)=Az ∝ Zrs-11/2, where rs is the mean interelectronic distance in the jellium model. Size effects are then considered, with possible relevance to atomic force microscopy.Defect energies are treated, using both electron theory and pair force laws.
基金This work was supported by the National Natural Science Foundation of China(Grant 11472016).
文摘As a basic principle in classical mechanics,the Galilean invariance states that the force is the same in all inertial frames of reference.But this principle has not been properly addressed by most unsteady aerodynamic force theories,if the partial force contributed by a local flow structure is to be evaluated.In this note,we discuss the Galilean-invariance conditions of the partial force for several typical theories and numerically test what would happen if these conditions do not hold.
基金Supported by the National Natural Science Foundation of China(51278220)
文摘The effects of the interactions between bi-directional pedestrians on the crossing time and the crosswalk width are studied. Firstly,the crossing process of bi-directional pedestrians is analyzed.The total crosswalk time is divided into a discharge time and a crossing time. The interactions between bi-directional pedestrians are quantified with the drag force theory. Then,a model is developed to study the crossing time based on the kinetic energy theory and momentum theory. Subsequently,the related parameters of the proposed model are calibrated with observed information. The relationships among crosswalk width,signal time,pedestrian volume and level of service are simulated with the proposed model. The results are verified and compared with other models. The proposed model has an absolute value of relative error of 9. 38%,which is smaller than that of the Alhajyaseen model( 15. 26%) and Highway Capacity Manual( HCM) model( 12. 42%). Finally,suggested crosswalk widths at different conditions are successfully estimated with the proposed crossing time model.
文摘With the rapid development of globalization, the whole world interweaves unprecedentedly. The frequent global communication is in desperate need of qualified translators and interpreters which draws great attention and invokes discussion about the standard of translation. Is the widely acknowledged criterion—neutral position a possible and necessary regulation to justify professional translators? This essay will illustrate that the interpreters influenced by environment, culture and other factors can’t perform with an absolute neutral position. Furthermore, the creativity of interpreters, who conduct heuristic work instead of algorithmic and reduplicated work, play a pivotal role in qualified work and their long-term development on the basis of Skopos Theory and classical examples, which testifies that it is improper to regard neutral position as a significant standard to evaluate the quality of interpreters.
文摘The study contains the justification of J.M. Herndon’s thesis about the existence of a thermonuclear reactor in the Earth’s core. A scenario of the formation of a spontaneous nuclear reactor is presented, referring to the universal law of gravity, to the relationship between matter and energy, and to the properties of plasma. The theoretical attitudes of the discussed phenomena and the relations between them can be called the Theory of the Primordial Forces of Nature. It includes the interactions of the gravitational field, the forces of the electromagnetic field, which determine the properties of matter, and the strong interactions resulting from the release of nuclear energy. Arguments for the thesis about the commonness of the phenomenon of thermonuclear reactors in space are presented. The second part of the article presents examples of geological phenomena that confirm the activity of a thermonuclear reactor in the center of the Earth.
基金supported by the Funds for Creative Research Groups of China(Grant No.51021004)the National Natural Science Foundation of China(Grant No.51509230)
文摘A new analytical expression for calculating the wave force on a composite bucket foundation is obtained. Based on the diffraction theory, the analytical solution of the wave pressure and the wave force on the composite bucket foundation is accurately derived by assigning reasonable boundary conditions. Experiments for the wave pressure on the bucket foundation with a scale of 1:60 under different wave conditions in the wave flume are designed and conducted. The analytical results agree well with the experimental data, and the theoretical approach can accurately predict the wave force on the large-scale structures. The wave pressure distribution on the composite bucket foundation is presented and the influence of the wave height, the water depth and the wave period on the wave force on the composite bucket foundation is investigated. This study provides a quite accurate method to calculate the wave force on a composite bucket foundation, which gives a good framework for future studies of the wave force on other large-scale structures with complex boundaries.
文摘Magnetotactic Bacteria (MTB) propel themselves by rotating their flagella and swim along the magnetic field lines. To analyze the motion of MTB, MTB magneto-ovoid strain MO-1 cells, each with two bundles of flagella, were taken as research object. The six-degrees-of-freedom (6-DoF) dynamic model of MO-1 was established based on the Newton-Euler dynamic equations. In particular, the interaction between the flagellum and fluid was considered by the resistive force theory. The simulated motion trajectory of MTB was found to consist of two kinds of helices: small helices restilting from the imbalance of force due to flagellar rotation, and large helices arising from the different directions of the rotation axis of the cell body and the propulsion axis of the flagellum. The motion behaviours of MTB in various magnetic fields were studied, and the simulation results agree well with the experiment results. In addition, the rotation frequency of the flagella was estimated at 1100 Hz, which is consistent with the average rotation rate for Na^+-driven flagellar motors. The included angle of the magnetosome chain was predicted at 40° that is located within 20° to 60° range of the observed results. The results indicate the correctness of the dynamic model, which may aid research on the operation and control of MTB-propelled micro-actuators. Meanwhile, the motion behaviours of MTB may inspire the development of micro-robots with new driving mechanisms.
文摘The Hayabusa2 asteroid explorer mission focuses principally on the touchdown and sampling on near-Earth asteroid 162173 Ryugu.Hayabusa2 successfully landed on its surface and ejected a projectile for sample collection on February 22,2019.Hayabusa2 later landed near a crater formed by an impactor and executed the sampling sequence again on July 11,2019.For a successful mission,a thorough understanding and evaluation of spacecraft dynamics during touchdown were crucial.The most challenging aspect of this study was the modeling of such spacecraft phenomena as the dynamics of landing on a surface with unknown properties.In particular,a Monte Carlo analysis was used to determine the parameters of the operational design for the final descent and touchdown sequence.This paper discusses the dynamical modeling of the simulation during the touchdown of Hayabusa2.
文摘Si dangling bonds at the interface of quasi-free-standing monolayer graphene (QFMLG) are known to act as scattering centers that can severely affect carrier mobility Herein, we investigate the atomic and electronic structure of Si dangling bonds in QFMLG using low-temperature scanning tunneling microscopy/ spectroscopy (STM/STS), atomic force microscopy (AFM), and density functional theory (DFT) calculations. Two types of defects with different contrast were observed on a flat graphene terrace by STM and AFM; in particular, their STM contrast varied with the bias voltage. Moreover, these defects showed characteristic STS peaks at different energies, 1.1 and 1.4 eV. The comparison of the experimental data with the DFT calculations indicates that the defects with STS peak energies of 1.1 and 1.4 eV consist of clusters of three and four Si dangling bonds, respectively. The relevance of the present results for the optimization of graphene synthesis is discussed.