A numerical simulation and an experimental study on vortex-induced motion（VIM） of a new type of deep draft multi-columns floating drilling production, storage and offloading（FDPSO） are presented in this paper. The...A numerical simulation and an experimental study on vortex-induced motion（VIM） of a new type of deep draft multi-columns floating drilling production, storage and offloading（FDPSO） are presented in this paper. The main dimension, the special variable cross-section column and the cabin arrangement of the octagonal pontoon are introduced based on the result. The numerical simulation is adapted to study the effects of current incidence angles and reduced velocities on this platform’s sway motion response. The 300 m water depth equivalent truncated mooring system is adopted for the model tests. The model tests are carried out to check the reliability of numerical simulation. The results consist of surge, sway and yaw motions, as well as motion trajectories. The maximum sway amplitudes for different types of offshore platform is also studied. The main results show that the peak frequencies of sway motion under different current incidence angles and reduced velocities vary around the natural frequency. The analysis result of flow field indicates that the change of distribution of vortex in vertical presents significant influences on the VIM of platform. The trend of sway amplitude ratio curve of this new type FDPSO differs from the other types of platform. Under 45° current incidence angle, the sway amplitude of this new type of FDPSO is much smaller than those of other types of offshore platform at 4.4 ≤ V;≤ 8.9. The typical ‘8’ shape trajectory does not appear in the platform’s motion trajectories.展开更多
To realize the application of the floating offshore wind turbine(FOWT)from deep to relatively shallow waters,a new concept of multi-column floating wind turbine platform with low center of gravity(CG)is designed and v...To realize the application of the floating offshore wind turbine(FOWT)from deep to relatively shallow waters,a new concept of multi-column floating wind turbine platform with low center of gravity(CG)is designed and validated.The multi-column low CG platform is designed to support a 6MW wind turbine class and operated at a water depth of 50m in the South China Sea.The frequency domain software WADAM and time domain software NREL-FAST are used to simulate coupled dynamic responses of the floating wind turbine system with second-order wave loads considering.The dynamic behaviors of multi-column low CG FOWT system under normal operation and parked conditions are presented.The influence of second-order wave force on the motion responses of the multi-column platform,fore-aft force and moment of the tower base and mooring force are researched respectively.The results demonstrate that the coupled dynamic responses at rated operating condition and extreme condition meet the normal operating requirements and extreme survival requirements of FOWT system in the shallow water(50m)of South China Sea.In addition,it is found that,the wave frequency response gradually replaces the second-order low frequency response as the main influencing factor of the coupled dynamic response of the FOWT system with the increasing severity of the sea states.However,in general,the magnitude of second-order low frequency response increases with the increasing severity of the design load case.Thus,in the subsequent design of the shallow water FOWT system,the second-order effects should be paid enough attention.展开更多
Cordyceps is a famous traditional Chinese medicine(TCM) that has been used in China for hundreds of years.In the present study a multi-column liquid chromatography(MC-LC) system was developed for the qualitative analy...Cordyceps is a famous traditional Chinese medicine(TCM) that has been used in China for hundreds of years.In the present study a multi-column liquid chromatography(MC-LC) system was developed for the qualitative analysis of macromolecules and micromolecules in Cordyceps.The MC-LC system includes a size exclusion pre-column,a size exclusion column(SEC) and a reversed phase column(RP) which were controlled by column-switching valves.The sample was separated by the size exclusion pre-column into two fractions(macromolecules and micromolecules).These fractions were further separated on SEC and RP columns,respectively.A diode array detector(DAD) and a mass spectrometer(MS) were used to detect the components.This MC-LC method was utilized for analysis of Cordyceps samples.Two macromolecular peaks and 15 micromolecular peaks were found in Cordyceps,and 11 of the micromolecular peaks were identified as adenosine-5'-monophosphate(AMP),phenylalanine,uridine,hypoxanthine,inosine,guanine,guanosine,deoxyadenosine-5'-monophosphate(dAMP),adenosine,adenine and cordycepin(or its isomer).This method is useful for quality control of Cordyceps.展开更多
Existing semantic segmentation networks based on the multi-column structure can hardly satisfy the efficiency and precision requirements simultaneously due to their shallow spatial branches.In this paper,we propose a ...Existing semantic segmentation networks based on the multi-column structure can hardly satisfy the efficiency and precision requirements simultaneously due to their shallow spatial branches.In this paper,we propose a new efficient multi-column network termed as LadderNet to address this problem.Our LadderNet includes two branches where the spatial branch generates high-resolution output feature map and the context branch encodes accurate semantic information.In particular,we first propose a channel attention fusion block and a global context module to enhance the information encoding ability of the context branch.Subsequently,a new branch fusion method,i.e.,fusing some middle feature maps of the context branch into the spatial branch,is developed to improve the depth of the spatial branch.Meanwhile,we design a feature fusing module to enhance the fusion quality of these two branches,leading to a more efficient network.We compare our model with other state-of-the-arts on PASCAL VOC 2012 and Cityscapes benchmarks.Experimental results demonstrate that,compared with other state-of-the-art methods,our LadderNet can achieve average 1.25%mIoU improvement with comparable or less computation.展开更多
基金financially supported by the National Natural Science Foundation of China(Grant No.51779109)the Natural Science Foundation of Jiangsu Province(Grant No.BK20171306)
文摘A numerical simulation and an experimental study on vortex-induced motion（VIM） of a new type of deep draft multi-columns floating drilling production, storage and offloading（FDPSO） are presented in this paper. The main dimension, the special variable cross-section column and the cabin arrangement of the octagonal pontoon are introduced based on the result. The numerical simulation is adapted to study the effects of current incidence angles and reduced velocities on this platform’s sway motion response. The 300 m water depth equivalent truncated mooring system is adopted for the model tests. The model tests are carried out to check the reliability of numerical simulation. The results consist of surge, sway and yaw motions, as well as motion trajectories. The maximum sway amplitudes for different types of offshore platform is also studied. The main results show that the peak frequencies of sway motion under different current incidence angles and reduced velocities vary around the natural frequency. The analysis result of flow field indicates that the change of distribution of vortex in vertical presents significant influences on the VIM of platform. The trend of sway amplitude ratio curve of this new type FDPSO differs from the other types of platform. Under 45° current incidence angle, the sway amplitude of this new type of FDPSO is much smaller than those of other types of offshore platform at 4.4 ≤ V;≤ 8.9. The typical ‘8’ shape trajectory does not appear in the platform’s motion trajectories.
基金support from the National Natural Science Foundation of China (No.51809170 and No.12102210)State Key Laboratory of Ocean Engi-neering (No.GKZD010081)Programfor International Coopera-tion of Shanghai Science and Technology (No.18160744000).
文摘To realize the application of the floating offshore wind turbine(FOWT)from deep to relatively shallow waters,a new concept of multi-column floating wind turbine platform with low center of gravity(CG)is designed and validated.The multi-column low CG platform is designed to support a 6MW wind turbine class and operated at a water depth of 50m in the South China Sea.The frequency domain software WADAM and time domain software NREL-FAST are used to simulate coupled dynamic responses of the floating wind turbine system with second-order wave loads considering.The dynamic behaviors of multi-column low CG FOWT system under normal operation and parked conditions are presented.The influence of second-order wave force on the motion responses of the multi-column platform,fore-aft force and moment of the tower base and mooring force are researched respectively.The results demonstrate that the coupled dynamic responses at rated operating condition and extreme condition meet the normal operating requirements and extreme survival requirements of FOWT system in the shallow water(50m)of South China Sea.In addition,it is found that,the wave frequency response gradually replaces the second-order low frequency response as the main influencing factor of the coupled dynamic response of the FOWT system with the increasing severity of the sea states.However,in general,the magnitude of second-order low frequency response increases with the increasing severity of the design load case.Thus,in the subsequent design of the shallow water FOWT system,the second-order effects should be paid enough attention.
基金supported by grant from the Science and Technology Development Fund of Macao(FDCT 059/2011/A3)
文摘Cordyceps is a famous traditional Chinese medicine(TCM) that has been used in China for hundreds of years.In the present study a multi-column liquid chromatography(MC-LC) system was developed for the qualitative analysis of macromolecules and micromolecules in Cordyceps.The MC-LC system includes a size exclusion pre-column,a size exclusion column(SEC) and a reversed phase column(RP) which were controlled by column-switching valves.The sample was separated by the size exclusion pre-column into two fractions(macromolecules and micromolecules).These fractions were further separated on SEC and RP columns,respectively.A diode array detector(DAD) and a mass spectrometer(MS) were used to detect the components.This MC-LC method was utilized for analysis of Cordyceps samples.Two macromolecular peaks and 15 micromolecular peaks were found in Cordyceps,and 11 of the micromolecular peaks were identified as adenosine-5'-monophosphate(AMP),phenylalanine,uridine,hypoxanthine,inosine,guanine,guanosine,deoxyadenosine-5'-monophosphate(dAMP),adenosine,adenine and cordycepin(or its isomer).This method is useful for quality control of Cordyceps.
基金the National Natural Science Foundation of China under Grant No.61773295。
文摘Existing semantic segmentation networks based on the multi-column structure can hardly satisfy the efficiency and precision requirements simultaneously due to their shallow spatial branches.In this paper,we propose a new efficient multi-column network termed as LadderNet to address this problem.Our LadderNet includes two branches where the spatial branch generates high-resolution output feature map and the context branch encodes accurate semantic information.In particular,we first propose a channel attention fusion block and a global context module to enhance the information encoding ability of the context branch.Subsequently,a new branch fusion method,i.e.,fusing some middle feature maps of the context branch into the spatial branch,is developed to improve the depth of the spatial branch.Meanwhile,we design a feature fusing module to enhance the fusion quality of these two branches,leading to a more efficient network.We compare our model with other state-of-the-arts on PASCAL VOC 2012 and Cityscapes benchmarks.Experimental results demonstrate that,compared with other state-of-the-art methods,our LadderNet can achieve average 1.25%mIoU improvement with comparable or less computation.
