The objective of this study is to show the effect of guide vane geometry on the performance. In order to overcome the disadvantages of vertical axis wind turbine, a straight-bladed vertical axis wind turbine （S-VAWT...The objective of this study is to show the effect of guide vane geometry on the performance. In order to overcome the disadvantages of vertical axis wind turbine, a straight-bladed vertical axis wind turbine （S-VAWT） with a directed guide vane row has been proposed and tested by the authors. According to previous studies, it was clarified that the performance of the turbine can be improved by means of the directed guide vane row. However, the guide vane geometry of S-VAWT has not been optimized so far. In order to clarify the effect of guide vanegeometry, the effects of setting angle and gap between rotor blade and guide vane on power coefticlent and start- ing characteristic were investigated in the experiments. The experimental study of the proposed wind turbine was carried out by a wind tunnel. The wind tunnel with a diameter of 1.8m is open jet type. The wind velocity is 8 m/s in the experiments. The rotor has three straight blades with a profile of NACA0018 and a chord length of 100 mm, a diameter of 0.6 m and a blade height of 0.7 m. The guide vane row consists of 3 arc plates.展开更多
目的探讨在彩色多普勒引导下经外周静脉置入中心静脉导管(peripherally inserted central catheter,PICC)置管穿刺过程中,采用平面内技术与平面外技术的应用效果。方法选取2015年1-12月在我院行超声引导下PICC置管患者130例,经患者知情...目的探讨在彩色多普勒引导下经外周静脉置入中心静脉导管(peripherally inserted central catheter,PICC)置管穿刺过程中,采用平面内技术与平面外技术的应用效果。方法选取2015年1-12月在我院行超声引导下PICC置管患者130例,经患者知情同意,按数字表法随机分为2组:超声引导下平面内技术组和平面外技术组,每组65例。观察2组穿刺用时和一针穿刺成功率。结果彩色多普勒引导下PICC置管穿刺过程中,平面内技术组穿刺时间为(180.0±35.0)s,平面外技术组为(98.0±24.1)s,2组比较差异有统计学意义(P<0.05);平面内技术组一针穿刺成功率为66.2%,平面外技术组为96.9%,2组比较差异有统计学意义(P<0.05)。结论超声引导下PICC置管平面外技术穿刺用时短,一针穿刺成功率高,适于在临床推广。展开更多
OBJECTIVE:To investigate the effect of spinal manipulation(SM)on degenerative scoliosis by evaluating patients’visual analog scale(VAS)scores,Cobb angles,sagittal vertical axis(SVA),and apical vertebral rotation(AVR)...OBJECTIVE:To investigate the effect of spinal manipulation(SM)on degenerative scoliosis by evaluating patients’visual analog scale(VAS)scores,Cobb angles,sagittal vertical axis(SVA),and apical vertebral rotation(AVR)and to explore factors that influence treatment effect.METHODS:A total of 55 patients with degenerative scoliosis received 4 weeks of SM.After treatment,patients were divided into two groups:the remission group(VAS score<40 mm)and the non-remission group(VAS score≥40 mm).Pre-versus post-treatment VAS scores,Cobb angles,SVA,and AVR were compared in each group and in the total population.Baseline data(sex,age,symptom characteristics,duration of symptoms,VAS score,Cobb angle,SVA,and AVR)were compared between groups.Factors influencing the post-treatment VAS score were explored with multiple linear regression analysis.RESULTS:No changes were found in the Cobb angle(P=0.722)or AVR(P=0.424)after intervention in the overall population.However,the SVA(P<0.001)and VAS score(P=0.000)changed significantly after treatment.Similar changes were observed in the remission group(n=29).Multiple linear regression revealed that the only factors influencing treatment effect were symptom characteristics,SVA,and VAS score.CONCLUSION:SM relieved pain and improved sagittal imbalance in patients with degenerative scoliosis.It did not lessen the severity of coronal curvature or vertebral rotation.Factors influencing the effect of SM included symptom characteristics,VAS score,and SVA.A larger randomized trial is needed to further confirm our results.展开更多
The objective of this study was to develop, as well as validate the strongly coupled method (two-way fluid structural interaction (FSI)) used to simulate the transient FSI response of the vertical axis tidal turbine (...The objective of this study was to develop, as well as validate the strongly coupled method (two-way fluid structural interaction (FSI)) used to simulate the transient FSI response of the vertical axis tidal turbine (VATT) rotor, subjected to spatially varying inflow. Moreover, this study examined strategies on improving techniques used for mesh deformation that account for large displacement or deformation calculations. The blade's deformation for each new time step is considered in transient two-way FSI analysis, to make the design more reliable. Usually this is not considered in routine one-way FSI simulations. A rotor with four blades and 4-m diameter was modeled and numerically analyzed. We observed that two-way FSI, utilizing the strongly coupled method, was impossible for a complex model; and thereby using ANSYS-CFX and ANSYS-MECHANICAL in work bench, as given in ANSYS-WORKBENCH, helped case examples 22 and 23, by giving an error when the solution was run. To make the method possible and reduce the computational power, a novel technique was used to transfer the file in ANSYS-APDL to obtain the solution and results. Consequently, the results indicating a two-way transient FSI analysis is a time- and resource-consuming job, but with our proposed technique we can reduce the computational time. The ANSYS STRUCTURAL results also uncover that stresses and deformations have higher values for two-way FSI as compared to one-way FSI. Similarly, fluid flow CFX results for two-way FSI are closer to experimental results as compared to one-way simulation results. Additionally, this study shows that, using the proposed method we can perform coupled simulation with simple multi-node PCs (core i5).展开更多
文摘The objective of this study is to show the effect of guide vane geometry on the performance. In order to overcome the disadvantages of vertical axis wind turbine, a straight-bladed vertical axis wind turbine （S-VAWT） with a directed guide vane row has been proposed and tested by the authors. According to previous studies, it was clarified that the performance of the turbine can be improved by means of the directed guide vane row. However, the guide vane geometry of S-VAWT has not been optimized so far. In order to clarify the effect of guide vanegeometry, the effects of setting angle and gap between rotor blade and guide vane on power coefticlent and start- ing characteristic were investigated in the experiments. The experimental study of the proposed wind turbine was carried out by a wind tunnel. The wind tunnel with a diameter of 1.8m is open jet type. The wind velocity is 8 m/s in the experiments. The rotor has three straight blades with a profile of NACA0018 and a chord length of 100 mm, a diameter of 0.6 m and a blade height of 0.7 m. The guide vane row consists of 3 arc plates.
文摘目的探讨在彩色多普勒引导下经外周静脉置入中心静脉导管(peripherally inserted central catheter,PICC)置管穿刺过程中,采用平面内技术与平面外技术的应用效果。方法选取2015年1-12月在我院行超声引导下PICC置管患者130例,经患者知情同意,按数字表法随机分为2组:超声引导下平面内技术组和平面外技术组,每组65例。观察2组穿刺用时和一针穿刺成功率。结果彩色多普勒引导下PICC置管穿刺过程中,平面内技术组穿刺时间为(180.0±35.0)s,平面外技术组为(98.0±24.1)s,2组比较差异有统计学意义(P<0.05);平面内技术组一针穿刺成功率为66.2%,平面外技术组为96.9%,2组比较差异有统计学意义(P<0.05)。结论超声引导下PICC置管平面外技术穿刺用时短,一针穿刺成功率高,适于在临床推广。
基金Supported by the Special Subject for the Construction of the National Traditional Chinese Medicine Clinical Research Base Effect of Spinal Manipulation on Degenerative Scoliosis and Factors Influencing Treatment Effect(JDZX2015271)Basic Scientific Research Project of Chinese Academy of Traditional Chinese Medicine Clinical and Experimental Study on Delaying The Degeneration of Bone and Joint(ZZ10-022)。
文摘OBJECTIVE:To investigate the effect of spinal manipulation(SM)on degenerative scoliosis by evaluating patients’visual analog scale(VAS)scores,Cobb angles,sagittal vertical axis(SVA),and apical vertebral rotation(AVR)and to explore factors that influence treatment effect.METHODS:A total of 55 patients with degenerative scoliosis received 4 weeks of SM.After treatment,patients were divided into two groups:the remission group(VAS score<40 mm)and the non-remission group(VAS score≥40 mm).Pre-versus post-treatment VAS scores,Cobb angles,SVA,and AVR were compared in each group and in the total population.Baseline data(sex,age,symptom characteristics,duration of symptoms,VAS score,Cobb angle,SVA,and AVR)were compared between groups.Factors influencing the post-treatment VAS score were explored with multiple linear regression analysis.RESULTS:No changes were found in the Cobb angle(P=0.722)or AVR(P=0.424)after intervention in the overall population.However,the SVA(P<0.001)and VAS score(P=0.000)changed significantly after treatment.Similar changes were observed in the remission group(n=29).Multiple linear regression revealed that the only factors influencing treatment effect were symptom characteristics,SVA,and VAS score.CONCLUSION:SM relieved pain and improved sagittal imbalance in patients with degenerative scoliosis.It did not lessen the severity of coronal curvature or vertebral rotation.Factors influencing the effect of SM included symptom characteristics,VAS score,and SVA.A larger randomized trial is needed to further confirm our results.
基金supported by the National Natural Science Foundation of China (Nos. 51209060 and 51106034)the ‘111’ Project Foundation from Ministry of Education and State Administration of Foreign Experts Affairs (No. B07019), Chinathe National Special Foundation for Ocean Energy (No. GHME2010CY01)
文摘The objective of this study was to develop, as well as validate the strongly coupled method (two-way fluid structural interaction (FSI)) used to simulate the transient FSI response of the vertical axis tidal turbine (VATT) rotor, subjected to spatially varying inflow. Moreover, this study examined strategies on improving techniques used for mesh deformation that account for large displacement or deformation calculations. The blade's deformation for each new time step is considered in transient two-way FSI analysis, to make the design more reliable. Usually this is not considered in routine one-way FSI simulations. A rotor with four blades and 4-m diameter was modeled and numerically analyzed. We observed that two-way FSI, utilizing the strongly coupled method, was impossible for a complex model; and thereby using ANSYS-CFX and ANSYS-MECHANICAL in work bench, as given in ANSYS-WORKBENCH, helped case examples 22 and 23, by giving an error when the solution was run. To make the method possible and reduce the computational power, a novel technique was used to transfer the file in ANSYS-APDL to obtain the solution and results. Consequently, the results indicating a two-way transient FSI analysis is a time- and resource-consuming job, but with our proposed technique we can reduce the computational time. The ANSYS STRUCTURAL results also uncover that stresses and deformations have higher values for two-way FSI as compared to one-way FSI. Similarly, fluid flow CFX results for two-way FSI are closer to experimental results as compared to one-way simulation results. Additionally, this study shows that, using the proposed method we can perform coupled simulation with simple multi-node PCs (core i5).
