The computational fluid dynamics （CFD） method is used to numerically simulate a propeller wake flow field in open water. A sub-domain hybrid mesh method was adopted in this paper. The computation domain was separate...The computational fluid dynamics （CFD） method is used to numerically simulate a propeller wake flow field in open water. A sub-domain hybrid mesh method was adopted in this paper. The computation domain was separated into two sub-domains, in which tetrahedral elements were used in the inner domain to match the complicated geometry of the propeller, while hexahedral elements were used in the outer domain. The mesh was locally refined on the propeller surface and near the wake flow field, and a size function was used to control the growth rate of the grid. Sections at different axial location were used to study the spatial evolution of the propeller wake in the region ranging from the disc to one propeller diameter （D） downstream. The numerical results show that the axial velocity fluctuates along the wake flow; radial velocity, which is closely related to vortices, attenuates strongly. The trailing vortices interact with the tip vortex at the blades＇ trailing edge and then separate. The strength of the vortex shrinks rapidly, and the radius decreases 20% at one diameter downstream.展开更多
Artificial bone with porous structure is crucial for tissue scaffold and clinic implants.Scaffold provides structure support for cells and guides tissues regeneration for final tissue structure.A computational aided p...Artificial bone with porous structure is crucial for tissue scaffold and clinic implants.Scaffold provides structure support for cells and guides tissues regeneration for final tissue structure.A computational aided process of porous bone modeling was developed which described the design and fabrication of tissue scaffolds by considering intricate architecture,porosity and pore size.To simulate intricate bone structure,different constructive units were presented.In modeling process,bone contour was gotten from computed tomography(CT)images and was divided into two levels.Each level was represented by relatively reconstructive process.Pore size distribution was controlled by using mesh generation.The whole hexahedral mesh was reduced by unit structure,when a 3D mesh with various hexahedral elements was provided.The simulation results show that constructive structure of porous scaffold can meet the needs of clinic implants in accurate and controlled way.展开更多
A brilliant purple octahedral single crystal is hydrothermally synthesized by the reaction of CoCl26H2O, H3BO3 and H3PO4 in NaOH aqueous solution of CH3(CH2)15N(CH3)3Br, and its crystal structure has been characterize...A brilliant purple octahedral single crystal is hydrothermally synthesized by the reaction of CoCl26H2O, H3BO3 and H3PO4 in NaOH aqueous solution of CH3(CH2)15N(CH3)3Br, and its crystal structure has been characterized by single-crystal X-ray diffraction. The compound, NaCo(H2O)2BP2O8稨2O (Mr = 336.72), belongs to hexagonal, space group P6122 with a = 9.447(5), c = 15.83(1) , V = 1223(1) 3, Dc = 2.742 g/cm3, Z = 6, F(000) = 1002 and m = 2.606 mm-1. The three-dimensional framework in the compound is built up from the linkage tetrahedral ribbons, in which the BO4 and PO4 tetrahedra alternate with CoO6 octahedra. The sodium ions and water molecules are located within the free thread of the helical ribbons.展开更多
In this gape, we obtain thorem I on volum of a n-dirmensional simplex and theorem 2 on dihedral angies of a simplex. Besides. We obtain Vasic inequality in E^n and its extension. The resultsin this paper contain and i...In this gape, we obtain thorem I on volum of a n-dirmensional simplex and theorem 2 on dihedral angies of a simplex. Besides. We obtain Vasic inequality in E^n and its extension. The resultsin this paper contain and improve the results in paper [1], [2], [3], [4].展开更多
In this work, we successfully synthesized bicrystalline anatase/TiO2（B） nanofibre and used it as active substrate for surface-enhanced Raman scattering （SERS） applications. The bicrystalline structured TiO2 substr...In this work, we successfully synthesized bicrystalline anatase/TiO2（B） nanofibre and used it as active substrate for surface-enhanced Raman scattering （SERS） applications. The bicrystalline structured TiO2 substrates provide additional charge transfer across the anatase-TiO2（B） interface and thus enhanced activity compared to the pure single crystalline phase. With an effort to further increase the sensitivity of SERS, nitrogen element was doped into bicrystalline anatase/TiO2（B） nanofibres （N-TiO2） and higher SERS enhancement was achieved. The nitrogen content was controlled by tuning the calcination temperature of titanate precursor at 500, 600 and 700℃, respectively. The sample calcined at 600℃ （NT600） acquires the highest percentage of nitrogen element due to its open pore structure that facilitates the diffusion of nitrogen during calcination. Raman intensity depends on the amount of nitrogen doping, thus NT600 exhibited the best SERS activity. The doped nitrogen in TiO2 facilitates the charge transfer between TiO2 and probing molecules and thus suppresses the electron-hole recombination. This work provides a new perspective on the design of efficient TiO2 SERS active substrate and is expected to be valuable for adsorbate detection on semiconductor surface.展开更多
Among the numerous inland river basins in the arid northwest China,Shiyang River basin is known for its most serious water shortage that constrains its social and economic developments and for some of the worst ecolog...Among the numerous inland river basins in the arid northwest China,Shiyang River basin is known for its most serious water shortage that constrains its social and economic developments and for some of the worst ecological and environmental deterioration in China.The research on the value of water resources used for ecosystem is the basis for reasonable allocation of water resources between users of ecosystem and economic system.In this paper the concept of dynamic value for the ecosystem services is proposed.A modified coefficient for the ecosystem service value per unit area is proposed according to the cover degrees of biomes combined with expert consultation.Based on the developmental stage coefficient and scarcity of ecological resources,a dynamic evaluation method is proposed.The theoretical formula and simple calculation formula of the sharing benefits coefficient and benefits per unit ecological water utilization are proposed.The result shows that the benefit of unit ecological water utilization in the lower reach was greater than that in the upper reach in the Shiyang River basin.展开更多
A novel surface active monomer （surfmer） containing poly（ethylene glycol） chain and terminated phosphate group was synthesized. The copolymerization of synthesized surfmer with NVP （N-vinylpyrrolidone） and with ...A novel surface active monomer （surfmer） containing poly（ethylene glycol） chain and terminated phosphate group was synthesized. The copolymerization of synthesized surfmer with NVP （N-vinylpyrrolidone） and with NVP and VEP （5-tert-butylperoxy-5-methyl-2-hexene-3-yne monomer） led to formation of corresponding surface-active copolymers. The capability of application of resulted copolymers as surface active macroinitiators of emulsion polymerization of styrene and as components of polymeric scaffolds was investigated.展开更多
基金Supported by Fundamental Research Funds for the Central Universities(Grant No.HEUCFT1001)Ph.D Programs Foundation of Ministry of Education of China(Grant No.10702016)
文摘The computational fluid dynamics （CFD） method is used to numerically simulate a propeller wake flow field in open water. A sub-domain hybrid mesh method was adopted in this paper. The computation domain was separated into two sub-domains, in which tetrahedral elements were used in the inner domain to match the complicated geometry of the propeller, while hexahedral elements were used in the outer domain. The mesh was locally refined on the propeller surface and near the wake flow field, and a size function was used to control the growth rate of the grid. Sections at different axial location were used to study the spatial evolution of the propeller wake in the region ranging from the disc to one propeller diameter （D） downstream. The numerical results show that the axial velocity fluctuates along the wake flow; radial velocity, which is closely related to vortices, attenuates strongly. The trailing vortices interact with the tip vortex at the blades＇ trailing edge and then separate. The strength of the vortex shrinks rapidly, and the radius decreases 20% at one diameter downstream.
基金Project(2011DFB70230)supported by State International Cooperation Program of ChinaProject(N110403003)supported by Basic Research Foundation of Education Ministry of China
文摘Artificial bone with porous structure is crucial for tissue scaffold and clinic implants.Scaffold provides structure support for cells and guides tissues regeneration for final tissue structure.A computational aided process of porous bone modeling was developed which described the design and fabrication of tissue scaffolds by considering intricate architecture,porosity and pore size.To simulate intricate bone structure,different constructive units were presented.In modeling process,bone contour was gotten from computed tomography(CT)images and was divided into two levels.Each level was represented by relatively reconstructive process.Pore size distribution was controlled by using mesh generation.The whole hexahedral mesh was reduced by unit structure,when a 3D mesh with various hexahedral elements was provided.The simulation results show that constructive structure of porous scaffold can meet the needs of clinic implants in accurate and controlled way.
基金NNSFC (No. 20173017) and State Key Basic Program (No. G2000048)
文摘A brilliant purple octahedral single crystal is hydrothermally synthesized by the reaction of CoCl26H2O, H3BO3 and H3PO4 in NaOH aqueous solution of CH3(CH2)15N(CH3)3Br, and its crystal structure has been characterized by single-crystal X-ray diffraction. The compound, NaCo(H2O)2BP2O8稨2O (Mr = 336.72), belongs to hexagonal, space group P6122 with a = 9.447(5), c = 15.83(1) , V = 1223(1) 3, Dc = 2.742 g/cm3, Z = 6, F(000) = 1002 and m = 2.606 mm-1. The three-dimensional framework in the compound is built up from the linkage tetrahedral ribbons, in which the BO4 and PO4 tetrahedra alternate with CoO6 octahedra. The sodium ions and water molecules are located within the free thread of the helical ribbons.
文摘In this gape, we obtain thorem I on volum of a n-dirmensional simplex and theorem 2 on dihedral angies of a simplex. Besides. We obtain Vasic inequality in E^n and its extension. The resultsin this paper contain and improve the results in paper [1], [2], [3], [4].
基金Supported by Chinese MOST 973 project(2013CB733501)the National Natural Science Foundation of China1(21136004,21476106,21606131)+1 种基金the Priority Academic Program Development of Jiangsu Higher Education Institutions(PAPD)the Fundamental Research Funds for the Central Universities(30916011351)at Nanjing University of Science&Technology
文摘In this work, we successfully synthesized bicrystalline anatase/TiO2（B） nanofibre and used it as active substrate for surface-enhanced Raman scattering （SERS） applications. The bicrystalline structured TiO2 substrates provide additional charge transfer across the anatase-TiO2（B） interface and thus enhanced activity compared to the pure single crystalline phase. With an effort to further increase the sensitivity of SERS, nitrogen element was doped into bicrystalline anatase/TiO2（B） nanofibres （N-TiO2） and higher SERS enhancement was achieved. The nitrogen content was controlled by tuning the calcination temperature of titanate precursor at 500, 600 and 700℃, respectively. The sample calcined at 600℃ （NT600） acquires the highest percentage of nitrogen element due to its open pore structure that facilitates the diffusion of nitrogen during calcination. Raman intensity depends on the amount of nitrogen doping, thus NT600 exhibited the best SERS activity. The doped nitrogen in TiO2 facilitates the charge transfer between TiO2 and probing molecules and thus suppresses the electron-hole recombination. This work provides a new perspective on the design of efficient TiO2 SERS active substrate and is expected to be valuable for adsorbate detection on semiconductor surface.
基金Supported by National Natural Science Foundation of China (No.50879071and No.40771034)the Special Research of Public Sector of Water Resources Ministry of China (No.200801104)
文摘Among the numerous inland river basins in the arid northwest China,Shiyang River basin is known for its most serious water shortage that constrains its social and economic developments and for some of the worst ecological and environmental deterioration in China.The research on the value of water resources used for ecosystem is the basis for reasonable allocation of water resources between users of ecosystem and economic system.In this paper the concept of dynamic value for the ecosystem services is proposed.A modified coefficient for the ecosystem service value per unit area is proposed according to the cover degrees of biomes combined with expert consultation.Based on the developmental stage coefficient and scarcity of ecological resources,a dynamic evaluation method is proposed.The theoretical formula and simple calculation formula of the sharing benefits coefficient and benefits per unit ecological water utilization are proposed.The result shows that the benefit of unit ecological water utilization in the lower reach was greater than that in the upper reach in the Shiyang River basin.
文摘A novel surface active monomer （surfmer） containing poly（ethylene glycol） chain and terminated phosphate group was synthesized. The copolymerization of synthesized surfmer with NVP （N-vinylpyrrolidone） and with NVP and VEP （5-tert-butylperoxy-5-methyl-2-hexene-3-yne monomer） led to formation of corresponding surface-active copolymers. The capability of application of resulted copolymers as surface active macroinitiators of emulsion polymerization of styrene and as components of polymeric scaffolds was investigated.
