Device physics research for submicron and deep submicron space microelectronics devices and integrated circuits will be described in three topics.1.Thin film submicron and deep submicron SOS / CMOS devices and integra...Device physics research for submicron and deep submicron space microelectronics devices and integrated circuits will be described in three topics.1.Thin film submicron and deep submicron SOS / CMOS devices and integrated circuits.2.Deep submicron LDD CMOS devices and integrated circuits.3.C band and Ku band microwave GaAs MESFET and III-V compound hetrojunction HEM T and HBT devices and integrated circuits.展开更多
Metrological analysis shows that any clock in inertial motion in infinite space shall not have time dilation, due to relativity of such motion in such space. On the other hand, atomic clock in inertial motion in finit...Metrological analysis shows that any clock in inertial motion in infinite space shall not have time dilation, due to relativity of such motion in such space. On the other hand, atomic clock in inertial motion in finite space shall exhibit time dilation, due to alteration of momentum of clock-defining particle caused by nonzero curvature of trajectory of such motion in such space. Therefore, time dilation experiment of atomic clock in inertial motion in physical space provides a direct and decisive way of determining geometry of physical space in real-time. Phenomenon of time dilation of atomic clock in inertial motion in physical space has long been observed and confirmed experimentally. Therefore, extent of physical space has to be finite, consistent with result of high precision experiment of free particle in high-speed motion conducted a decade ago.Keywords Geometry of Physical Space, Time Dilation, Atomic Clock, Special Relativity Theory.展开更多
Plurality of characteristic peaks observed in number density distribution of galaxy redshift reveals that extent of physical space has been finite. Significant portion of observed celestial objects is found pair-wise ...Plurality of characteristic peaks observed in number density distribution of galaxy redshift reveals that extent of physical space has been finite. Significant portion of observed celestial objects is found pair-wise associated, i.e., the observed lights were emitted from one and same luminescent source but seen at different sky directions of observer, which is a unique phenomenon that can occur but only in finite space. Cosmic microwave radiation has always been interpreted as afterglow of Big Bang event. However, such radiation is shown unobservable to current observer if Hubble-Lemaître Correlation is interpreted as caused by receding motion of celestial objects. On the other hand, cosmic radiation can be understood as a common and ordinary phenomenon due to space lens, a unique property only of finite space. From Sloan Digital Sky Survey data, internal diameter of physical space is measured as 2.0 billion light years. If celestial objects were receding, hence physical space was expanding, then characteristic peaks of finite physical space should not appear evenly in number density distribution of redshift of the objects but more sparsely with respect to redshift increase. However, as revealed by the data, locations of the characteristic peaks in the distributions are rather even that do not match the locations as required by receding motion of object. Therefore, as evidenced by the data, physical space was not expanding, at least during the recent 18 billion years. In addition, considerable portion of observed quasars is found sharing a common factor of ~1/2 for their respective gravitation redshifts.展开更多
The Chinese Antarctic Great Wall, Zhongshan, Kunlun and Arctic Yellow River stations have unique geographical locations, well suited to carry out polar upper atmospheric observations. This paper reviews the tremendous...The Chinese Antarctic Great Wall, Zhongshan, Kunlun and Arctic Yellow River stations have unique geographical locations, well suited to carry out polar upper atmospheric observations. This paper reviews the tremendous history of nearly 30 years of Chinese polar expeditions and major progress in polar upper atmospheric physics research. This includes the polar upper atmospheric physics conjugate observation system at Zhongshan Station in the Antarctic and Yellow River Station in the Arctic, and original research achievements in polar ionospheric fields, aurora and particle precipitation, the polar current system, polar plasma convection, geomagnetic pulsations and space plasma waves, inter-hemispheric comparisons of the space environment, space weather in polar regions, power spectrum of the incoherent scatter radar, ionospheric heating experiments and polar meso- spheric summer echoes, polar ionosphere-magnetosphere numerical simulation and others. Finally, prospects for Chinese polar upper atmospheric physics research are outlined.展开更多
The theoretical framework of visual simulation in virtual reality is discussed. The new concept of visual image space is supposed. On the basis of visual image space, in visual perceptive sense, VR is considered as a ...The theoretical framework of visual simulation in virtual reality is discussed. The new concept of visual image space is supposed. On the basis of visual image space, in visual perceptive sense, VR is considered as a spatial simulation. The objective of the spatial simulation is to transform physical space to visual image space. Last, the prototype system, surveying & mapping virtual Reality (SMVR), is developed, and the space simulation above is realized. By use of SMVR, the real 3D representation, 3D visual analysis, virtual plan and designs can be implemented.展开更多
The anisotropic physical property is the most noteworthy feature of crystals.In this paper,the subscript change method is used to analyze the sign changes of different tensors describing physical properties in uniaxia...The anisotropic physical property is the most noteworthy feature of crystals.In this paper,the subscript change method is used to analyze the sign changes of different tensors describing physical properties in uniaxial crystals.The distribution of some physical properties in special point groups exhibits non-symmetry in eight quadrants,which should attract the attention of crystal research.The difference between the crystallographic and physical coordinate systems and the lack of crystal symmetry operations are considered to be the origins of the non-symmetry.To avoid ambiguities and difficulties in characterizing and applying crystal physical properties,eight quadrants in space should be clarified.Hence,we proposed the use of piezoelectric properties to define the positive direction of the optical coordinate axis prior to the research and applications of optical properties.展开更多
The four-dimensional variational assimilation(4D-Var)has been widely used in meteorological and oceanographic data assimilation.This method is usually implemented in the model space,known as primal approach(P4D-Var).A...The four-dimensional variational assimilation(4D-Var)has been widely used in meteorological and oceanographic data assimilation.This method is usually implemented in the model space,known as primal approach(P4D-Var).Alternatively,physical space analysis system(4D-PSAS)is proposed to reduce the computation cost,in which the 4D-Var problem is solved in physical space(i.e.,observation space).In this study,the conjugate gradient(CG)algorithm,implemented in the 4D-PSAS system is evaluated and it is found that the non-monotonic change of the gradient norm of 4D-PSAS cost function causes artificial oscillations of cost function in the iteration process.The reason of non-monotonic variation of gradient norm in 4D-PSAS is then analyzed.In order to overcome the non-monotonic variation of gradient norm,a new algorithm,Minimum Residual(MINRES)algorithm,is implemented in the process of assimilation iteration in this study.Our experimental results show that the improved 4D-PSAS with the MINRES algorithm guarantees the monotonic reduction of gradient norm of cost function,greatly improves the convergence properties of 4D-PSAS as well,and significantly restrains the numerical noises associated with the traditional 4D-PSAS system.展开更多
Spaces of informality, such as favelas, barriadas and tugurios are seen by media, municipalities and security institutions as dangerous places. Today municipalities and international agencies use new forms of urban up...Spaces of informality, such as favelas, barriadas and tugurios are seen by media, municipalities and security institutions as dangerous places. Today municipalities and international agencies use new forms of urban upgrading as tools to address both the traditional structural problems of poverty and also as tools for violence prevention. While a causation between informal spaces and insecurity clearly does not exist, there is an interest in understanding the influence of physical interventions in neighborhood security behavior. This research tests ways in which urban projects alter perceptions of security among favela dwellers over time, in the Rio de Janeiro "Favela-Bairro" urban upgrading project. Finds that while security conditions are marginally affected, location close to main roads part of the urban upgrading project affect residents' security perceptions positively. However, individuals in less accessible areas of the favela present less openness to address security questions. It argues that individual proximity to upgraded main roads experience shelter from the effects of retaliation from perverse actors than those that have their accessibility impeded. Other projects such as public spaces or buildings show no significative changes in security perceptions.展开更多
The closure of a turbulence field is a longstanding fundamental problem, while most closure models are introduced in spectral space. Inspired by Chou's quasi-normal closure method in spectral space, we propose an ana...The closure of a turbulence field is a longstanding fundamental problem, while most closure models are introduced in spectral space. Inspired by Chou's quasi-normal closure method in spectral space, we propose an analytical closure model for isotropic turbulence based on the extended scale similarity theory of the velocity structure function in physical space. The assumptions and certain approximations are justified with direct numerical simulation. The asymptotic scaling properties are reproduced by this new closure method, in comparison to the classical Batchelor model.展开更多
The present study has evaluated the effect of architectural forms on the walking activity of citizens as a behavioral model in urban physical spaces.The research hypothesis claims that by designing purposeful and appr...The present study has evaluated the effect of architectural forms on the walking activity of citizens as a behavioral model in urban physical spaces.The research hypothesis claims that by designing purposeful and appropriate architectural forms,the behavior and actions of users in urban physical spaces can be to some extent,it designed or controlled,and that the pattern and domains of human behavior in urban streets are the result of the components of environmental quality that are included in the design of that street.The present theoretical proposition has been tested in two sequences from Valiasr Street in Tehran.At the theoretical level,the research method is descriptive-analytical and at the experimental level,it is a survey that has been done using the behavioral research method.The results show that the floor form and street form are the most influential architectural forms in urban physical spaces on the activity of users walking from space in the study sample.Also,some environmental factors have a direct effect on human reactions;The research findings show that people’s speed is directly related to the dimensions of sidewalk carpets and a person tries to take a step according to the senses he receives from the sidewalk flooring form and as a result his speed changes according to those forms.展开更多
The expressions for calculating the values of the workspace areas of 2-DOF parallel planar manipulators (PPM) is derived. By the aid of computer, the values are calculated and plotted on the physical model o...The expressions for calculating the values of the workspace areas of 2-DOF parallel planar manipulators (PPM) is derived. By the aid of computer, the values are calculated and plotted on the physical model of the solution space of the 2-DOF PPMs,so the workspaee-area-property atlas is obtained. The atlas delineates the relationship between the workspace areas and the link lengths of the 2-DOF PPMs all-sidedly. It is very useful for designers overalI to understand and know welI the relationship.展开更多
Existence of gravitation inverse matter in finite space is shown inevitable. As an example, direction of gravitation of rest mass of electron is opposite to that of positron. That is, electron and positron are gravita...Existence of gravitation inverse matter in finite space is shown inevitable. As an example, direction of gravitation of rest mass of electron is opposite to that of positron. That is, electron and positron are gravitationally repulsive to each other. The physical space has previously been shown of finite extent. Therefore, if gravitation normal matter is found prevailing in the physical space then, according to the law of mass/charge balance in finite space, the Universe, i.e., the physical space and all that it contains/confines, must be a shell-structured black hole in a higher dimensional space.展开更多
The Chinese Meridian Project(CMP)is a major national science and technology infrastructure invested and constructed by the Chinese government.The project builds space environment observation stations,focusing on the m...The Chinese Meridian Project(CMP)is a major national science and technology infrastructure invested and constructed by the Chinese government.The project builds space environment observation stations,focusing on the monitoring of the space environment over China,so as to provide a monitoring basis for clarifying the regional characteristics of the space environment over China and its relationship with global change,and making important innovative scientific achievements.The first phase of the CMP passed the national acceptance in 2012.It has been running for nearly ten years and has accumulated more than 8 TB monitoring data.These data are all available to all data users through the data center of the project.From 2020 to 2021,users of CMP data have completed a series of original works,which have solved current scientific problems in the field of space physics research.On the other hand,they also make us look forward to the completion of the second phase of CMP and its application benefits in national major strategic needs and cutting-edge scientific research.展开更多
The parametric excited vibration of a pipe under thermal loading may occur because the fluid is often transported heatedly. The effects of thermal loading on the pipe stability and local bifurcations have rarely been ...The parametric excited vibration of a pipe under thermal loading may occur because the fluid is often transported heatedly. The effects of thermal loading on the pipe stability and local bifurcations have rarely been studied. The stability and the local bifurcations of the lateral parametric resonance of the pipe induced by the pulsating fluid velocity and the thermal loading are studied. A mathematical model for a simply supported pipe is developed according to the Hamilton principle. Two partial differential equations describing the lateral and longitudinal vibration are obtained. The singularity theory is utilized to anMyze the stability and the bifurcation of the system solutions. The transition sets and the bifurcation diagrams are obtained both in the unfolding parameter space and the physical parameter space, which can reveal the relationship between the thermal field parameter and the dynamic behaviors of the pipe. The frequency response and the relationship between the critical thermal rate and the pulsating fluid velocity are obtained. The numerical results demonstrate the accuracy of the single-mode expansion of the solution and the stability and local bifurcation analyses. It also confirms the existence of the chaos. The presented work can provide valuable information for the design of the pipeline and the controllers to prevent the structural instability.展开更多
In this paper,an analytical model is used to analyze the modulated polar mesospheric winter echoes(PMWE).The winter parameters were introduced to simulate the effects of different parameters during the artificial elec...In this paper,an analytical model is used to analyze the modulated polar mesospheric winter echoes(PMWE).The winter parameters were introduced to simulate the effects of different parameters during the artificial electron heating of PMWE.The important role of the charged dust particle in the creation of PMWE is confirmed again.It is found that during the heating of PMWE,the increases of the dust size,dust charge,electron temperature,initial electron density,and ion-neutral collision frequency cause the increase of the electron density irregularity,and hence the PMWE strength.However,with increasing the dust density,the electron density irregularity and the PMWE strength decrease.展开更多
Microgravity science is an important branch of space science.Its major objective is to study the laws of materials movement in microgravity,as well as to reveal the influence of gravity on the movement of materials in...Microgravity science is an important branch of space science.Its major objective is to study the laws of materials movement in microgravity,as well as to reveal the influence of gravity on the movement of materials in different gravity environments.Application researches relevant to these basic studies are also important contents of microgravity science.The advanced subjects,to some extent,reflect the ability of human beings to understand nature and the R&D level in this field in various countries.In this paper,the recent progress and the latest achievements of microgravity science and application researches in China aboard space platforms such as the Core Capsule Tianhe of the China Space Station(CSS)and satellites,as well as utilizing ground-based short-term microgravity facilities such as the Drop Tower Beijing and TUFF,are summarized,which cover the following sub-disciplines:microgravity fluid physics,microgravity combustion science,space materials science,space fundamental physics,space bio-technology,and relevant space technology applications.展开更多
The phonon relaxation and heat conduction in one-dimensional Fermi Pasta-Ulam (FPU) β lattices are studied by using molecular dynamics simulations. The phonon relaxation rate, which dominates the length dependence ...The phonon relaxation and heat conduction in one-dimensional Fermi Pasta-Ulam (FPU) β lattices are studied by using molecular dynamics simulations. The phonon relaxation rate, which dominates the length dependence of the FPU β lattice, is first calculated from the energy autoeorrelation function for different modes at various temperatures through equilibrium molecular dynamics simulations. We find that the relaxation rate as a function of wave number k is proportional to k^1.688, which leads to a N^0.41 divergence of the thermal conductivity in the framework of Green-Kubo relation. This is also in good agreement with the data obtained by non-equilibrium molecular dynamics simulations which estimate the length dependence exponent of the thermal conductivity as 0.415. Our results confirm the N^2/5 divergence in one-dimensional FPU β lattices. The effects of the heat flux on the thermal conductivity are also studied by imposing different temperature differences on the two ends of the lattices. We find that the thermal conductivity is insensitive to the heat flux under our simulation conditions. It implies that the linear response theory is applicable towards the heat conduction in one-dimensional FPU β lattices.展开更多
Facilities planning tools have been used by project managers for planning industry spaces for decades now, but applications in creative organizations are still sparse. This happens mainly because of a gap that exists ...Facilities planning tools have been used by project managers for planning industry spaces for decades now, but applications in creative organizations are still sparse. This happens mainly because of a gap that exists between engineering and psychology fields, with the first developing planning tools for production but with little concern for creativity and the other developing spaces for creativity, but with a lack of tools. Both try to solve the same issue: fostering productivity in the workplace, but they need to be linked first, in order to accomplish it. How to close this gap? Can a project manager plan the facilities for a creative organizational in the best way possible? In this paper, a new approach is used for studying the design of physical environments that foster organizational creativity, combining the results of psychological studies on the impact of physical environment on creativity with the facilities planning body of knowledge applied by industrial engineers. In order to test the results, a single case study is developed in a small IT consulting firm. By using the systematic layout planning (SLP) step by step process, it is shown that by acting on the work environment of the company, the developers creative processes can be boosted and facilitated. It is also shown that both industrial engineering and creativity research have much to contribute to each other and future research topics in the field are presented.展开更多
Digital twin(DT)can achieve real-time information fusion and interactive feedback between virtual space and physical space.This technology involves a digital model,real-time information management,comprehensive intell...Digital twin(DT)can achieve real-time information fusion and interactive feedback between virtual space and physical space.This technology involves a digital model,real-time information management,comprehensive intelligent perception networks,etc.,and it can drive the rapid conceptual development of intelligent construction(IC)such as smart factories,smart cities,and smart medical care.Nevertheless,the actual use of DT in IC is partially pending,with numerous scientific factors still not clarified.An overall survey on pending issues and unsolved scientific factors is needed for the development of DT-driven IC.To this end,this study aims to provide a comprehensive review of the state of the art and state of the use of DT-driven IC.The use of DT in planning,design,manufacturing,operation,and maintenance management of IC is demonstrated and analyzed,following which the driving functions of DT in IC are detailed from four aspects:information perception and analysis,data mining and modeling,state assessment and prediction,intelligent optimization and decision-making.Furthermore,the future direction of research,using DT in IC,is presented with some comments and suggestions.This work will help researchers gain in-depth and systematic understanding of the use of DT,and help practitioners to better promote its implementation in IC.展开更多
In Waterland,contemporary British writer Graham Swift tells the protagonist Tom,using a mix of reality and history recreates the ecological devastation of the Fens Marsh,the fall of the Atkinson family and the spiritu...In Waterland,contemporary British writer Graham Swift tells the protagonist Tom,using a mix of reality and history recreates the ecological devastation of the Fens Marsh,the fall of the Atkinson family and the spiritual collapse of the people.This paper attempts to explore the dilemma of human existence by starting from Henry’s spatial theory and dividing it into physical space,social space and mental space.展开更多
文摘Device physics research for submicron and deep submicron space microelectronics devices and integrated circuits will be described in three topics.1.Thin film submicron and deep submicron SOS / CMOS devices and integrated circuits.2.Deep submicron LDD CMOS devices and integrated circuits.3.C band and Ku band microwave GaAs MESFET and III-V compound hetrojunction HEM T and HBT devices and integrated circuits.
文摘Metrological analysis shows that any clock in inertial motion in infinite space shall not have time dilation, due to relativity of such motion in such space. On the other hand, atomic clock in inertial motion in finite space shall exhibit time dilation, due to alteration of momentum of clock-defining particle caused by nonzero curvature of trajectory of such motion in such space. Therefore, time dilation experiment of atomic clock in inertial motion in physical space provides a direct and decisive way of determining geometry of physical space in real-time. Phenomenon of time dilation of atomic clock in inertial motion in physical space has long been observed and confirmed experimentally. Therefore, extent of physical space has to be finite, consistent with result of high precision experiment of free particle in high-speed motion conducted a decade ago.Keywords Geometry of Physical Space, Time Dilation, Atomic Clock, Special Relativity Theory.
文摘Plurality of characteristic peaks observed in number density distribution of galaxy redshift reveals that extent of physical space has been finite. Significant portion of observed celestial objects is found pair-wise associated, i.e., the observed lights were emitted from one and same luminescent source but seen at different sky directions of observer, which is a unique phenomenon that can occur but only in finite space. Cosmic microwave radiation has always been interpreted as afterglow of Big Bang event. However, such radiation is shown unobservable to current observer if Hubble-Lemaître Correlation is interpreted as caused by receding motion of celestial objects. On the other hand, cosmic radiation can be understood as a common and ordinary phenomenon due to space lens, a unique property only of finite space. From Sloan Digital Sky Survey data, internal diameter of physical space is measured as 2.0 billion light years. If celestial objects were receding, hence physical space was expanding, then characteristic peaks of finite physical space should not appear evenly in number density distribution of redshift of the objects but more sparsely with respect to redshift increase. However, as revealed by the data, locations of the characteristic peaks in the distributions are rather even that do not match the locations as required by receding motion of object. Therefore, as evidenced by the data, physical space was not expanding, at least during the recent 18 billion years. In addition, considerable portion of observed quasars is found sharing a common factor of ~1/2 for their respective gravitation redshifts.
文摘The Chinese Antarctic Great Wall, Zhongshan, Kunlun and Arctic Yellow River stations have unique geographical locations, well suited to carry out polar upper atmospheric observations. This paper reviews the tremendous history of nearly 30 years of Chinese polar expeditions and major progress in polar upper atmospheric physics research. This includes the polar upper atmospheric physics conjugate observation system at Zhongshan Station in the Antarctic and Yellow River Station in the Arctic, and original research achievements in polar ionospheric fields, aurora and particle precipitation, the polar current system, polar plasma convection, geomagnetic pulsations and space plasma waves, inter-hemispheric comparisons of the space environment, space weather in polar regions, power spectrum of the incoherent scatter radar, ionospheric heating experiments and polar meso- spheric summer echoes, polar ionosphere-magnetosphere numerical simulation and others. Finally, prospects for Chinese polar upper atmospheric physics research are outlined.
文摘The theoretical framework of visual simulation in virtual reality is discussed. The new concept of visual image space is supposed. On the basis of visual image space, in visual perceptive sense, VR is considered as a spatial simulation. The objective of the spatial simulation is to transform physical space to visual image space. Last, the prototype system, surveying & mapping virtual Reality (SMVR), is developed, and the space simulation above is realized. By use of SMVR, the real 3D representation, 3D visual analysis, virtual plan and designs can be implemented.
基金Project supported by the National Natural Science Foundation of China(Grant Nos.51772170,51572155,and 11504389)the National Key Research and Development Program of China(Grant No.2016YFB1102201)the Young Scholars Program(Grant No.2018WLJH67).
文摘The anisotropic physical property is the most noteworthy feature of crystals.In this paper,the subscript change method is used to analyze the sign changes of different tensors describing physical properties in uniaxial crystals.The distribution of some physical properties in special point groups exhibits non-symmetry in eight quadrants,which should attract the attention of crystal research.The difference between the crystallographic and physical coordinate systems and the lack of crystal symmetry operations are considered to be the origins of the non-symmetry.To avoid ambiguities and difficulties in characterizing and applying crystal physical properties,eight quadrants in space should be clarified.Hence,we proposed the use of piezoelectric properties to define the positive direction of the optical coordinate axis prior to the research and applications of optical properties.
基金The National Key Research and Development Program of China under contract Nos 2017YFC1501803 and2018YFC1506903the National Natural Science Foundation of China under contract Nos 91730304,41475021 and 41575026
文摘The four-dimensional variational assimilation(4D-Var)has been widely used in meteorological and oceanographic data assimilation.This method is usually implemented in the model space,known as primal approach(P4D-Var).Alternatively,physical space analysis system(4D-PSAS)is proposed to reduce the computation cost,in which the 4D-Var problem is solved in physical space(i.e.,observation space).In this study,the conjugate gradient(CG)algorithm,implemented in the 4D-PSAS system is evaluated and it is found that the non-monotonic change of the gradient norm of 4D-PSAS cost function causes artificial oscillations of cost function in the iteration process.The reason of non-monotonic variation of gradient norm in 4D-PSAS is then analyzed.In order to overcome the non-monotonic variation of gradient norm,a new algorithm,Minimum Residual(MINRES)algorithm,is implemented in the process of assimilation iteration in this study.Our experimental results show that the improved 4D-PSAS with the MINRES algorithm guarantees the monotonic reduction of gradient norm of cost function,greatly improves the convergence properties of 4D-PSAS as well,and significantly restrains the numerical noises associated with the traditional 4D-PSAS system.
文摘Spaces of informality, such as favelas, barriadas and tugurios are seen by media, municipalities and security institutions as dangerous places. Today municipalities and international agencies use new forms of urban upgrading as tools to address both the traditional structural problems of poverty and also as tools for violence prevention. While a causation between informal spaces and insecurity clearly does not exist, there is an interest in understanding the influence of physical interventions in neighborhood security behavior. This research tests ways in which urban projects alter perceptions of security among favela dwellers over time, in the Rio de Janeiro "Favela-Bairro" urban upgrading project. Finds that while security conditions are marginally affected, location close to main roads part of the urban upgrading project affect residents' security perceptions positively. However, individuals in less accessible areas of the favela present less openness to address security questions. It argues that individual proximity to upgraded main roads experience shelter from the effects of retaliation from perverse actors than those that have their accessibility impeded. Other projects such as public spaces or buildings show no significative changes in security perceptions.
文摘The closure of a turbulence field is a longstanding fundamental problem, while most closure models are introduced in spectral space. Inspired by Chou's quasi-normal closure method in spectral space, we propose an analytical closure model for isotropic turbulence based on the extended scale similarity theory of the velocity structure function in physical space. The assumptions and certain approximations are justified with direct numerical simulation. The asymptotic scaling properties are reproduced by this new closure method, in comparison to the classical Batchelor model.
文摘The present study has evaluated the effect of architectural forms on the walking activity of citizens as a behavioral model in urban physical spaces.The research hypothesis claims that by designing purposeful and appropriate architectural forms,the behavior and actions of users in urban physical spaces can be to some extent,it designed or controlled,and that the pattern and domains of human behavior in urban streets are the result of the components of environmental quality that are included in the design of that street.The present theoretical proposition has been tested in two sequences from Valiasr Street in Tehran.At the theoretical level,the research method is descriptive-analytical and at the experimental level,it is a survey that has been done using the behavioral research method.The results show that the floor form and street form are the most influential architectural forms in urban physical spaces on the activity of users walking from space in the study sample.Also,some environmental factors have a direct effect on human reactions;The research findings show that people’s speed is directly related to the dimensions of sidewalk carpets and a person tries to take a step according to the senses he receives from the sidewalk flooring form and as a result his speed changes according to those forms.
文摘The expressions for calculating the values of the workspace areas of 2-DOF parallel planar manipulators (PPM) is derived. By the aid of computer, the values are calculated and plotted on the physical model of the solution space of the 2-DOF PPMs,so the workspaee-area-property atlas is obtained. The atlas delineates the relationship between the workspace areas and the link lengths of the 2-DOF PPMs all-sidedly. It is very useful for designers overalI to understand and know welI the relationship.
文摘Existence of gravitation inverse matter in finite space is shown inevitable. As an example, direction of gravitation of rest mass of electron is opposite to that of positron. That is, electron and positron are gravitationally repulsive to each other. The physical space has previously been shown of finite extent. Therefore, if gravitation normal matter is found prevailing in the physical space then, according to the law of mass/charge balance in finite space, the Universe, i.e., the physical space and all that it contains/confines, must be a shell-structured black hole in a higher dimensional space.
文摘The Chinese Meridian Project(CMP)is a major national science and technology infrastructure invested and constructed by the Chinese government.The project builds space environment observation stations,focusing on the monitoring of the space environment over China,so as to provide a monitoring basis for clarifying the regional characteristics of the space environment over China and its relationship with global change,and making important innovative scientific achievements.The first phase of the CMP passed the national acceptance in 2012.It has been running for nearly ten years and has accumulated more than 8 TB monitoring data.These data are all available to all data users through the data center of the project.From 2020 to 2021,users of CMP data have completed a series of original works,which have solved current scientific problems in the field of space physics research.On the other hand,they also make us look forward to the completion of the second phase of CMP and its application benefits in national major strategic needs and cutting-edge scientific research.
基金Project supported by the National Natural Science Foundation of Shandong Province(No.ZR2013AL017)the National Natural Science Foundation of China(No.11272357)the Fundamental Research Funds for the Central Universities of China(No.11CX04049A)
文摘The parametric excited vibration of a pipe under thermal loading may occur because the fluid is often transported heatedly. The effects of thermal loading on the pipe stability and local bifurcations have rarely been studied. The stability and the local bifurcations of the lateral parametric resonance of the pipe induced by the pulsating fluid velocity and the thermal loading are studied. A mathematical model for a simply supported pipe is developed according to the Hamilton principle. Two partial differential equations describing the lateral and longitudinal vibration are obtained. The singularity theory is utilized to anMyze the stability and the bifurcation of the system solutions. The transition sets and the bifurcation diagrams are obtained both in the unfolding parameter space and the physical parameter space, which can reveal the relationship between the thermal field parameter and the dynamic behaviors of the pipe. The frequency response and the relationship between the critical thermal rate and the pulsating fluid velocity are obtained. The numerical results demonstrate the accuracy of the single-mode expansion of the solution and the stability and local bifurcation analyses. It also confirms the existence of the chaos. The presented work can provide valuable information for the design of the pipeline and the controllers to prevent the structural instability.
基金supported by the National Natural Science Foundation of China under Grants No. 61671116 and No. 11905026Fundamental Research Funds for the Central Universities under Grants No. ZYGX2019Z006 and No. ZYGX2019J012。
文摘In this paper,an analytical model is used to analyze the modulated polar mesospheric winter echoes(PMWE).The winter parameters were introduced to simulate the effects of different parameters during the artificial electron heating of PMWE.The important role of the charged dust particle in the creation of PMWE is confirmed again.It is found that during the heating of PMWE,the increases of the dust size,dust charge,electron temperature,initial electron density,and ion-neutral collision frequency cause the increase of the electron density irregularity,and hence the PMWE strength.However,with increasing the dust density,the electron density irregularity and the PMWE strength decrease.
文摘Microgravity science is an important branch of space science.Its major objective is to study the laws of materials movement in microgravity,as well as to reveal the influence of gravity on the movement of materials in different gravity environments.Application researches relevant to these basic studies are also important contents of microgravity science.The advanced subjects,to some extent,reflect the ability of human beings to understand nature and the R&D level in this field in various countries.In this paper,the recent progress and the latest achievements of microgravity science and application researches in China aboard space platforms such as the Core Capsule Tianhe of the China Space Station(CSS)and satellites,as well as utilizing ground-based short-term microgravity facilities such as the Drop Tower Beijing and TUFF,are summarized,which cover the following sub-disciplines:microgravity fluid physics,microgravity combustion science,space materials science,space fundamental physics,space bio-technology,and relevant space technology applications.
基金Project supported by the National Natural Science Foundation of China(Grant Nos.50976052,51136001,and 50730006)the Program for New Century Excellent Talents in University,China+1 种基金the Tsinghua University Initiative Scientific Research Program,Chinathe Tsinghua National Laboratory for Information Science and Technology TNList Cross-discipline Foundation,China
文摘The phonon relaxation and heat conduction in one-dimensional Fermi Pasta-Ulam (FPU) β lattices are studied by using molecular dynamics simulations. The phonon relaxation rate, which dominates the length dependence of the FPU β lattice, is first calculated from the energy autoeorrelation function for different modes at various temperatures through equilibrium molecular dynamics simulations. We find that the relaxation rate as a function of wave number k is proportional to k^1.688, which leads to a N^0.41 divergence of the thermal conductivity in the framework of Green-Kubo relation. This is also in good agreement with the data obtained by non-equilibrium molecular dynamics simulations which estimate the length dependence exponent of the thermal conductivity as 0.415. Our results confirm the N^2/5 divergence in one-dimensional FPU β lattices. The effects of the heat flux on the thermal conductivity are also studied by imposing different temperature differences on the two ends of the lattices. We find that the thermal conductivity is insensitive to the heat flux under our simulation conditions. It implies that the linear response theory is applicable towards the heat conduction in one-dimensional FPU β lattices.
文摘Facilities planning tools have been used by project managers for planning industry spaces for decades now, but applications in creative organizations are still sparse. This happens mainly because of a gap that exists between engineering and psychology fields, with the first developing planning tools for production but with little concern for creativity and the other developing spaces for creativity, but with a lack of tools. Both try to solve the same issue: fostering productivity in the workplace, but they need to be linked first, in order to accomplish it. How to close this gap? Can a project manager plan the facilities for a creative organizational in the best way possible? In this paper, a new approach is used for studying the design of physical environments that foster organizational creativity, combining the results of psychological studies on the impact of physical environment on creativity with the facilities planning body of knowledge applied by industrial engineers. In order to test the results, a single case study is developed in a small IT consulting firm. By using the systematic layout planning (SLP) step by step process, it is shown that by acting on the work environment of the company, the developers creative processes can be boosted and facilitated. It is also shown that both industrial engineering and creativity research have much to contribute to each other and future research topics in the field are presented.
基金the financial support partially provided by The Quality Engineering Project of Anhui Province(2019sjjd58,2020sxzx36)The Ministry of Education Cooperative Education Project(201901119016)+1 种基金The Chinese(Jiangsu)-Czech Bilateral Co-funding R&D Project(SBZ2018000220)the Key R&D Project of Anhui Science and Technology Department(202004b11020026).
文摘Digital twin(DT)can achieve real-time information fusion and interactive feedback between virtual space and physical space.This technology involves a digital model,real-time information management,comprehensive intelligent perception networks,etc.,and it can drive the rapid conceptual development of intelligent construction(IC)such as smart factories,smart cities,and smart medical care.Nevertheless,the actual use of DT in IC is partially pending,with numerous scientific factors still not clarified.An overall survey on pending issues and unsolved scientific factors is needed for the development of DT-driven IC.To this end,this study aims to provide a comprehensive review of the state of the art and state of the use of DT-driven IC.The use of DT in planning,design,manufacturing,operation,and maintenance management of IC is demonstrated and analyzed,following which the driving functions of DT in IC are detailed from four aspects:information perception and analysis,data mining and modeling,state assessment and prediction,intelligent optimization and decision-making.Furthermore,the future direction of research,using DT in IC,is presented with some comments and suggestions.This work will help researchers gain in-depth and systematic understanding of the use of DT,and help practitioners to better promote its implementation in IC.
文摘In Waterland,contemporary British writer Graham Swift tells the protagonist Tom,using a mix of reality and history recreates the ecological devastation of the Fens Marsh,the fall of the Atkinson family and the spiritual collapse of the people.This paper attempts to explore the dilemma of human existence by starting from Henry’s spatial theory and dividing it into physical space,social space and mental space.