A simplified approach was proposed to analyze the negative skin friction calculation of special-shaped pile considering pile-soil interaction under surcharge. Based on the concentric cylinder shearing theory, consider...A simplified approach was proposed to analyze the negative skin friction calculation of special-shaped pile considering pile-soil interaction under surcharge. Based on the concentric cylinder shearing theory, considering the changes of pile shape(such as, taper angle and diameters of pile base, etc.), the load-transfer of special-shaped pile was built. The accuracy of the developed simplified approach was verified by numerical simulation model with the same condition. Then, the influence factors, such as, taper angles, the diameter of pile base, surcharge, and pile-soil interface parameters were analyzed and discussed. The results show that the developed simplified approach can calculate NSF of special-shaped pile under surcharge effectively. A limited parametric study indicates that in many practical situations special-shaped piles(such as belled wedge pile shown in this work) offer a design option that is more economical than traditional uniform cross-section piles.展开更多
The reaction of Co_2(CO)_8 with EtSPCl_2 gives a new crystal like compound Co_7(μ_7-S)(μ_4-PSEt)(μ- SEt)_2(μ-CO)_2(CO)_(12),whose structure has been determined by single crystal x-ray diffraction.This special com-...The reaction of Co_2(CO)_8 with EtSPCl_2 gives a new crystal like compound Co_7(μ_7-S)(μ_4-PSEt)(μ- SEt)_2(μ-CO)_2(CO)_(12),whose structure has been determined by single crystal x-ray diffraction.This special com- pound reveals some new features in cluster chemistry^1:The fragmentation of a ligand precursor EtSPCl_2 yields three kinds of fragments,μ_7-S,μ_4-PSEt and μ-SEt,which are ligands in the same cluster molecule.There is a new type of bridging S presented——A μ_7-S atom is interspaced into seven Co core.展开更多
Four exterior joints with special-shaped columns which have different lengths of limbs are tested under low cyclic loading. Speeial-shaped columns adopted are L- and T-shaped in section. It can be concluded that crack...Four exterior joints with special-shaped columns which have different lengths of limbs are tested under low cyclic loading. Speeial-shaped columns adopted are L- and T-shaped in section. It can be concluded that crack pattern, failure mode and shear strength of joints are affected by the length of limb, and that shear strength and ductility increase with the length of limb; the joints with the flexural failure of the beam have better seismic behavior than those with the shear failure of the joint core.展开更多
Driven by the rapid economic development,the development of transportation in China has begun to move towards mountainous areas.The climate environment,topography and landform of mountainous cities are different from ...Driven by the rapid economic development,the development of transportation in China has begun to move towards mountainous areas.The climate environment,topography and landform of mountainous cities are different from those of plain areas.In mountainous cities,the area of opposite interchanges between expressways and urban roads is generally large,which has a certain contradiction with the topographic conditions of mountainous cities.Therefore,it is necessary to reasonably design the opposite interchanges between expressways and urban roads in mountainous cities.The author explores and analyzes the factors restricting the special-shaped interchange between expressway and urban road in mountainous cities and the main fbnns of special-shaped interchange,and puts forward a reasonable design scheme,hoping to make a smooth development of the special-shaped interchange in mountainous cities.展开更多
Profile grinding is the most crucial method for the ultra-precision machining of special-shaped surfaces.However,profile grinding produces a unique machining profile,and many random factors in the machining process le...Profile grinding is the most crucial method for the ultra-precision machining of special-shaped surfaces.However,profile grinding produces a unique machining profile,and many random factors in the machining process lead to complex surface characteristics.In this study,the structural and probabilistic characteristics of the profile grinding of a special-shaped surface were analyzed,and a probabilistic algorithm for the forming and 3D characterization of special-shaped surfaces under profile grinding was developed.The forming process of a GH738 blade tenon tooth surface was considered as an example to demonstrate the algorithm.The comparison results showed that the simulation results had similar surface characteristics to the measurement results,and the relative error range of the 3D roughness parameter was 0.21%–19.76%,indicating an accurate prediction and characterization of the complex special-shaped surface under the action of multiple factors.展开更多
With the help of Complex Function Mapping theory, the complicated three-dimensional deformation problems are transferred into two-dimensional problems, and the function of strain ratio field is analyzed in the metal p...With the help of Complex Function Mapping theory, the complicated three-dimensional deformation problems are transferred into two-dimensional problems, and the function of strain ratio field is analyzed in the metal plastic extruding deformation. Taking the strain-hardening effect of metal deformation into account, the relationship between friction behavior and optimized mathematical model is analyzed by the numerical analysis friction energy dissipation function. As a result, the method of lowering the material hardening and decreasing the reduction ratio over multi-procedures can be used to improve the surface quality of metal special-shape extrusion products.展开更多
We report the current status of Taimen (Hucho taimen) population in Wusuli River of China. The amount of catch per year was only 1 800 - 5 400 individuals ranging from 2-15 years old during 1998-2002. Of all the captu...We report the current status of Taimen (Hucho taimen) population in Wusuli River of China. The amount of catch per year was only 1 800 - 5 400 individuals ranging from 2-15 years old during 1998-2002. Of all the captured, individuals with sexual maturity were up to 30%-70% (female maturity at 5 years old and male 6 years old). Sex ratio varied greatly among different localities. Its breeding population mainly consisted of males aged 5-10 years and females aged 8-13 years’old, which spawned in May each year.Females breed once with about 4 000 - 23 000 eggs produced every 2-3 years. Taimen grows fast and average growth rate is about 10 cm per year prior to 10 years’s old, which corresponded with von Bertelanffy’s equation calculated as L t=246 41[1-e -0 0407(t-0 4625) ] and W t= 174 075 72 [1-e -0 0407(t-0 4622) ] 2 9537 , and the relationship between body length and weight was W=0 015018L u 2020 .展开更多
基金Projects(51278170,U1134207)supported by the National Natural Science Foundation of ChinaProject(B13024)supported by the Program of Introducing Talents of Discipline to Universities,China
文摘A simplified approach was proposed to analyze the negative skin friction calculation of special-shaped pile considering pile-soil interaction under surcharge. Based on the concentric cylinder shearing theory, considering the changes of pile shape(such as, taper angle and diameters of pile base, etc.), the load-transfer of special-shaped pile was built. The accuracy of the developed simplified approach was verified by numerical simulation model with the same condition. Then, the influence factors, such as, taper angles, the diameter of pile base, surcharge, and pile-soil interface parameters were analyzed and discussed. The results show that the developed simplified approach can calculate NSF of special-shaped pile under surcharge effectively. A limited parametric study indicates that in many practical situations special-shaped piles(such as belled wedge pile shown in this work) offer a design option that is more economical than traditional uniform cross-section piles.
文摘The reaction of Co_2(CO)_8 with EtSPCl_2 gives a new crystal like compound Co_7(μ_7-S)(μ_4-PSEt)(μ- SEt)_2(μ-CO)_2(CO)_(12),whose structure has been determined by single crystal x-ray diffraction.This special com- pound reveals some new features in cluster chemistry^1:The fragmentation of a ligand precursor EtSPCl_2 yields three kinds of fragments,μ_7-S,μ_4-PSEt and μ-SEt,which are ligands in the same cluster molecule.There is a new type of bridging S presented——A μ_7-S atom is interspaced into seven Co core.
文摘Four exterior joints with special-shaped columns which have different lengths of limbs are tested under low cyclic loading. Speeial-shaped columns adopted are L- and T-shaped in section. It can be concluded that crack pattern, failure mode and shear strength of joints are affected by the length of limb, and that shear strength and ductility increase with the length of limb; the joints with the flexural failure of the beam have better seismic behavior than those with the shear failure of the joint core.
文摘Driven by the rapid economic development,the development of transportation in China has begun to move towards mountainous areas.The climate environment,topography and landform of mountainous cities are different from those of plain areas.In mountainous cities,the area of opposite interchanges between expressways and urban roads is generally large,which has a certain contradiction with the topographic conditions of mountainous cities.Therefore,it is necessary to reasonably design the opposite interchanges between expressways and urban roads in mountainous cities.The author explores and analyzes the factors restricting the special-shaped interchange between expressway and urban road in mountainous cities and the main fbnns of special-shaped interchange,and puts forward a reasonable design scheme,hoping to make a smooth development of the special-shaped interchange in mountainous cities.
基金sponsored by the National Natural Science Foundation of China(Grant No.51905442)the National Major Science and Technology Projects of China(Grant No.2017-VII-0002-0095).
文摘Profile grinding is the most crucial method for the ultra-precision machining of special-shaped surfaces.However,profile grinding produces a unique machining profile,and many random factors in the machining process lead to complex surface characteristics.In this study,the structural and probabilistic characteristics of the profile grinding of a special-shaped surface were analyzed,and a probabilistic algorithm for the forming and 3D characterization of special-shaped surfaces under profile grinding was developed.The forming process of a GH738 blade tenon tooth surface was considered as an example to demonstrate the algorithm.The comparison results showed that the simulation results had similar surface characteristics to the measurement results,and the relative error range of the 3D roughness parameter was 0.21%–19.76%,indicating an accurate prediction and characterization of the complex special-shaped surface under the action of multiple factors.
文摘With the help of Complex Function Mapping theory, the complicated three-dimensional deformation problems are transferred into two-dimensional problems, and the function of strain ratio field is analyzed in the metal plastic extruding deformation. Taking the strain-hardening effect of metal deformation into account, the relationship between friction behavior and optimized mathematical model is analyzed by the numerical analysis friction energy dissipation function. As a result, the method of lowering the material hardening and decreasing the reduction ratio over multi-procedures can be used to improve the surface quality of metal special-shape extrusion products.
文摘We report the current status of Taimen (Hucho taimen) population in Wusuli River of China. The amount of catch per year was only 1 800 - 5 400 individuals ranging from 2-15 years old during 1998-2002. Of all the captured, individuals with sexual maturity were up to 30%-70% (female maturity at 5 years old and male 6 years old). Sex ratio varied greatly among different localities. Its breeding population mainly consisted of males aged 5-10 years and females aged 8-13 years’old, which spawned in May each year.Females breed once with about 4 000 - 23 000 eggs produced every 2-3 years. Taimen grows fast and average growth rate is about 10 cm per year prior to 10 years’s old, which corresponded with von Bertelanffy’s equation calculated as L t=246 41[1-e -0 0407(t-0 4625) ] and W t= 174 075 72 [1-e -0 0407(t-0 4622) ] 2 9537 , and the relationship between body length and weight was W=0 015018L u 2020 .
