Through combined applications of the transfer-matrix method and asymptotic expansion technique,we formulate a theory to predict the three-dimensional response of micropolar plates.No ad hoc assumptions regarding throu...Through combined applications of the transfer-matrix method and asymptotic expansion technique,we formulate a theory to predict the three-dimensional response of micropolar plates.No ad hoc assumptions regarding through-thickness assumptions of the field variables are made,and the governing equations are two-dimensional,with the displacements and microrotations of the mid-plane as the unknowns.Once the deformation of the mid-plane is solved,a three-dimensional micropolar elastic field within the plate is generated,which is exact up to the second order except in the boundary region close to the plate edge.As an illustrative example,the bending of a clamped infinitely long plate caused by a uniformly distributed transverse force is analyzed and discussed in detail.展开更多
Urban expansion is a phenomenon of urban space increase,and an important measuring index of the process of urbanization.Taking Shanghai as an example,the changes of urban average height and built-up area were studied ...Urban expansion is a phenomenon of urban space increase,and an important measuring index of the process of urbanization.Taking Shanghai as an example,the changes of urban average height and built-up area were studied to represent city's vertical and horizontal increases respectively,and statistical methods were used to analyze the driving forces of urban expansion.The research drew following conclusions:1) The urban expansion process of Shanghai from 1985 to 2006 had a clear periodic feature,and could be divided into three stages:vertical expansion in dominance,coordinated vertical and horizontal expansion,and horizontal expansion in dominance.2) The average height and quantity of buildings in core city were significantly bigger than those in suburbs,but the changing speed of the latter was faster.And 3) urbanization process was the major driving force for the city's horizontal expansion,while industrial structure improvement was the key driving factor for the vertical expansion.Those two driving forces were simultaneously affected by city's political factors.展开更多
With rapid urban development in China in the last two decades, the three-dimensional(3D) characteristic has been the main feature of urban morphology. However, the vast majority of researches of urban growth have focu...With rapid urban development in China in the last two decades, the three-dimensional(3D) characteristic has been the main feature of urban morphology. However, the vast majority of researches of urban growth have focused on the planar area(two-dimensional(2D)) expansion. Few studies have been conducted from a 3D perspective. In this paper, the 3D urban expansion of the Yangzhou City, Jiangsu Province, China from 2003 to 2012 was evaluated based on Geographical Information System(GIS) tools and high-resolution remote sensing images. Four indices, namely weighted average height of buildings, volume of buildings, 3D expansion intensity and 3D fractal dimension are used to quantify the 3D urban expansion. The weighted average height of buildings and the volume of buildings are used to illustrate the temporal change of the 3D urban morphology, while the other two indices are used to calculate the expansion intensity and the fractal dimension of the 3D urban morphology. The results show that the spatial distribution of the high-rise buildings in Yangzhou has significantly spread and the utilization of the 3D space of Yangzhou has become more efficient and intensive. The methods proposed in this paper laid a foundation for a wide range of study of 3D urban morphology changes.展开更多
The in vitro expansion of stem cells is important for their application in different life science fields such as cellular tissue and organ repair.An objective of this paper was to achieve static cell culture in vitro ...The in vitro expansion of stem cells is important for their application in different life science fields such as cellular tissue and organ repair.An objective of this paper was to achieve static cell culture in vitro through peptide hydrogel-supported microspheres(MSs).The peptides,with their gel-forming properties,microstructures,and mechanical strengths characterized,were found to have good support for the MSs and to be injectable.The internal structures of poly(L-lactic acid)microspheres(PLLA-MSs)and polystyrene microspheres(PS-MSs)made in thelaboratory were observed and statistically analyzed in terms of particle size and pore size,following which the co-cultured MSs with cells were found to have good cell adhesion.In addition,three-dimensional(3D)culturing of cells was performed on the peptide and microcarrier composite scaffolds to measure cell viability and cell proliferation.The results showed that the peptides could be stimulated by the culture medium to self-assembly form a 3D fiber network structure.Under the peptide-Ms composite scaffold-based cell culture system,further enhancement of the cell culture effect was measured.The peptide-Ms composite scaffolds have great potential for the application in 3D cell culture and in vitro cellexpansion.展开更多
Although widely applied in treating hematopoietic malignancies,transplantation of hematopoietic stem/progenitor cells(HSPCs)is impeded by HSPC shortage.Whether circulating HSPCs(cHSPCs)in steady-state blood could be u...Although widely applied in treating hematopoietic malignancies,transplantation of hematopoietic stem/progenitor cells(HSPCs)is impeded by HSPC shortage.Whether circulating HSPCs(cHSPCs)in steady-state blood could be used as an alternative source remains largely elusive.Here we develop a three-dimensional culture system(3DCS)including arginine,glycine,aspartate,and a series of factors.Fourteen-day culture of peripheral blood mononuclear cells(PBMNCs)in 3DCS led to 125-and 70-fold increase of the frequency and number of CD34+cells.Further,3DCS-expanded cHSPCs exhibited the similar reconstitution rate com-pared to CD34+HSPCs in bone marrow.Mechanistically,3DCS fabricated an immunomodulatory niche,secreting cytokines as TNF to support cHSPC survival and proliferation.Finally,3DCS could also promote the expansion of cHSPCs in patients who failed in HSPC mobilization.Our 3DCS successfully expands rare cHSPCs,providing an alternative source for the HSPC therapy,particularly for the patients/donors who have failed in HSPC mobilization.展开更多
Based on two- and three-dimensional potential flow theories, the width effects on the hydrodynamics of a bottom-hinged trapezoidal pendulum wave energy converter are discussed. The two-dimensional eigenfunction expans...Based on two- and three-dimensional potential flow theories, the width effects on the hydrodynamics of a bottom-hinged trapezoidal pendulum wave energy converter are discussed. The two-dimensional eigenfunction expansion method is used to obtain the diffraction and radiation solutions when the converter width tends to be infinity. The trapezoidal section of the converter is approximated by a rectangular section for simplification. The nonlinear viscous damping effects are accounted for by including a drag term in the two- and three-dimensional methods. It is found that the three- dimensional results are in good agreement with the two-dimensional results when the converter width becomes larger, especially when the converter width is infinity, which shows that both of the methods are reasonable. Meantime, it is also found that the peak value of the conversion efficiency decreases as the converter width increases in short wave periods while increases when the converter width increases in long wave periods.展开更多
With high-resolution data of the Magnetospheric Multiscale(MMS) mission, we observe a magnetic flux rope(MFR) in the Earth's magnetosheath. This MFR, showing a clear bipolar variation of the magnetic field in the ...With high-resolution data of the Magnetospheric Multiscale(MMS) mission, we observe a magnetic flux rope(MFR) in the Earth's magnetosheath. This MFR, showing a clear bipolar variation of the magnetic field in the normal component to local current sheet, contains a strong core field. We use the FOTE method to reconstruct the topology of this MFR and find it is consistent with previous expectation. For the first time, the spiral field and core field of the MFR are both revealed from the FOTE method. Comparing topologies reconstructed at different times, we suggest that the axis of the MFR rotates about 88° at different spatial location. Shape and size of the normal projection to axis vary with the spatial location as well. Inside the MFR, a significant increase of plasma density from 40 to 80 cm^(-3), a sharp decrease of ion temperature from 200 to 50 eV, an enhancement of cold ions and a series of filamentary currents are found.展开更多
An analysis of the flow in the gap between a rotating cone and a stationary plate at low Reynolds numbers is presented. Using series expansions for the components of the mean velocity profile and the pressure gradient...An analysis of the flow in the gap between a rotating cone and a stationary plate at low Reynolds numbers is presented. Using series expansions for the components of the mean velocity profile and the pressure gradient the Navier-Stokes equations and the continuity equation for a Newtonian fluid written in cylindrical coordinates are solved. It is found that the solution is stable and convergent for the local Reynolds numbers Re smaller than 1.2928. The computed angle of the wall streamlines is found to be in good agreement with experimental data.展开更多
基金Project supported by the National Natural Science Foundation of China (No. 12072337)。
文摘Through combined applications of the transfer-matrix method and asymptotic expansion technique,we formulate a theory to predict the three-dimensional response of micropolar plates.No ad hoc assumptions regarding through-thickness assumptions of the field variables are made,and the governing equations are two-dimensional,with the displacements and microrotations of the mid-plane as the unknowns.Once the deformation of the mid-plane is solved,a three-dimensional micropolar elastic field within the plate is generated,which is exact up to the second order except in the boundary region close to the plate edge.As an illustrative example,the bending of a clamped infinitely long plate caused by a uniformly distributed transverse force is analyzed and discussed in detail.
基金Under the auspices of the Key Direction in Knowledge Innovation Programs of Chinese Academy of Sciences (No KZCX2-YW-422)National Natural Science Foundation of China (No 40701059)
文摘Urban expansion is a phenomenon of urban space increase,and an important measuring index of the process of urbanization.Taking Shanghai as an example,the changes of urban average height and built-up area were studied to represent city's vertical and horizontal increases respectively,and statistical methods were used to analyze the driving forces of urban expansion.The research drew following conclusions:1) The urban expansion process of Shanghai from 1985 to 2006 had a clear periodic feature,and could be divided into three stages:vertical expansion in dominance,coordinated vertical and horizontal expansion,and horizontal expansion in dominance.2) The average height and quantity of buildings in core city were significantly bigger than those in suburbs,but the changing speed of the latter was faster.And 3) urbanization process was the major driving force for the city's horizontal expansion,while industrial structure improvement was the key driving factor for the vertical expansion.Those two driving forces were simultaneously affected by city's political factors.
基金Under the auspices of Major Project of National Social Science Foundation of China(No.13&ZD13027)National Science&Technology Pillar Program During 12th Five-year Plan Period(No.2012BAJ22B03-04)National Natural Science Foundation of China(No.41401164)
文摘With rapid urban development in China in the last two decades, the three-dimensional(3D) characteristic has been the main feature of urban morphology. However, the vast majority of researches of urban growth have focused on the planar area(two-dimensional(2D)) expansion. Few studies have been conducted from a 3D perspective. In this paper, the 3D urban expansion of the Yangzhou City, Jiangsu Province, China from 2003 to 2012 was evaluated based on Geographical Information System(GIS) tools and high-resolution remote sensing images. Four indices, namely weighted average height of buildings, volume of buildings, 3D expansion intensity and 3D fractal dimension are used to quantify the 3D urban expansion. The weighted average height of buildings and the volume of buildings are used to illustrate the temporal change of the 3D urban morphology, while the other two indices are used to calculate the expansion intensity and the fractal dimension of the 3D urban morphology. The results show that the spatial distribution of the high-rise buildings in Yangzhou has significantly spread and the utilization of the 3D space of Yangzhou has become more efficient and intensive. The methods proposed in this paper laid a foundation for a wide range of study of 3D urban morphology changes.
基金supported by the National Key Research andDevelopment Program of China(Grant No.2021YFC2101400).
文摘The in vitro expansion of stem cells is important for their application in different life science fields such as cellular tissue and organ repair.An objective of this paper was to achieve static cell culture in vitro through peptide hydrogel-supported microspheres(MSs).The peptides,with their gel-forming properties,microstructures,and mechanical strengths characterized,were found to have good support for the MSs and to be injectable.The internal structures of poly(L-lactic acid)microspheres(PLLA-MSs)and polystyrene microspheres(PS-MSs)made in thelaboratory were observed and statistically analyzed in terms of particle size and pore size,following which the co-cultured MSs with cells were found to have good cell adhesion.In addition,three-dimensional(3D)culturing of cells was performed on the peptide and microcarrier composite scaffolds to measure cell viability and cell proliferation.The results showed that the peptides could be stimulated by the culture medium to self-assembly form a 3D fiber network structure.Under the peptide-Ms composite scaffold-based cell culture system,further enhancement of the cell culture effect was measured.The peptide-Ms composite scaffolds have great potential for the application in 3D cell culture and in vitro cellexpansion.
基金Data and materials availability:Processed and raw data can be downloaded from NCBI GEO(#GSE122682,and#GSE153421).
文摘Although widely applied in treating hematopoietic malignancies,transplantation of hematopoietic stem/progenitor cells(HSPCs)is impeded by HSPC shortage.Whether circulating HSPCs(cHSPCs)in steady-state blood could be used as an alternative source remains largely elusive.Here we develop a three-dimensional culture system(3DCS)including arginine,glycine,aspartate,and a series of factors.Fourteen-day culture of peripheral blood mononuclear cells(PBMNCs)in 3DCS led to 125-and 70-fold increase of the frequency and number of CD34+cells.Further,3DCS-expanded cHSPCs exhibited the similar reconstitution rate com-pared to CD34+HSPCs in bone marrow.Mechanistically,3DCS fabricated an immunomodulatory niche,secreting cytokines as TNF to support cHSPC survival and proliferation.Finally,3DCS could also promote the expansion of cHSPCs in patients who failed in HSPC mobilization.Our 3DCS successfully expands rare cHSPCs,providing an alternative source for the HSPC therapy,particularly for the patients/donors who have failed in HSPC mobilization.
基金supported by the Special Fund for Marine Renewable Energy of the Ministry of Finance of China(No.GD2010ZC02)
文摘Based on two- and three-dimensional potential flow theories, the width effects on the hydrodynamics of a bottom-hinged trapezoidal pendulum wave energy converter are discussed. The two-dimensional eigenfunction expansion method is used to obtain the diffraction and radiation solutions when the converter width tends to be infinity. The trapezoidal section of the converter is approximated by a rectangular section for simplification. The nonlinear viscous damping effects are accounted for by including a drag term in the two- and three-dimensional methods. It is found that the three- dimensional results are in good agreement with the two-dimensional results when the converter width becomes larger, especially when the converter width is infinity, which shows that both of the methods are reasonable. Meantime, it is also found that the peak value of the conversion efficiency decreases as the converter width increases in short wave periods while increases when the converter width increases in long wave periods.
基金supported by the National Natural Science Foundation of China(Grant Nos.41574153,41431071,and 41404133)
文摘With high-resolution data of the Magnetospheric Multiscale(MMS) mission, we observe a magnetic flux rope(MFR) in the Earth's magnetosheath. This MFR, showing a clear bipolar variation of the magnetic field in the normal component to local current sheet, contains a strong core field. We use the FOTE method to reconstruct the topology of this MFR and find it is consistent with previous expectation. For the first time, the spiral field and core field of the MFR are both revealed from the FOTE method. Comparing topologies reconstructed at different times, we suggest that the axis of the MFR rotates about 88° at different spatial location. Shape and size of the normal projection to axis vary with the spatial location as well. Inside the MFR, a significant increase of plasma density from 40 to 80 cm^(-3), a sharp decrease of ion temperature from 200 to 50 eV, an enhancement of cold ions and a series of filamentary currents are found.
文摘An analysis of the flow in the gap between a rotating cone and a stationary plate at low Reynolds numbers is presented. Using series expansions for the components of the mean velocity profile and the pressure gradient the Navier-Stokes equations and the continuity equation for a Newtonian fluid written in cylindrical coordinates are solved. It is found that the solution is stable and convergent for the local Reynolds numbers Re smaller than 1.2928. The computed angle of the wall streamlines is found to be in good agreement with experimental data.