A discontinuous Galerkin finite element method （DG-FEM） is developed for solving the axisymmetric Euler equations based on two-dimensional conservation laws. The method is used to simulate the unsteady-state underex...A discontinuous Galerkin finite element method （DG-FEM） is developed for solving the axisymmetric Euler equations based on two-dimensional conservation laws. The method is used to simulate the unsteady-state underexpanded axisymmetric jet. Several flow property distributions along the jet axis, including density, pres- sure and Mach number are obtained and the qualitative flowfield structures of interest are well captured using the proposed method, including shock waves, slipstreams, traveling vortex ring and multiple Mach disks. Two Mach disk locations agree well with computational and experimental measurement results. It indicates that the method is robust and efficient for solving the unsteady-state underexpanded axisymmetric jet.展开更多
A method for a vehicle durability emission test using a robot driver insteadof human drivers on the chassis dynamometer is presented. The system architecture of vehicledurability emission test cell, the road load simu...A method for a vehicle durability emission test using a robot driver insteadof human drivers on the chassis dynamometer is presented. The system architecture of vehicledurability emission test cell, the road load simulation strategy and the tele-monitoring systembased on Browser/Client structure are described. Furthermore, the construction of the robot driver,vehicle performance self-learning algorithm, multi-mode vehicle control model and vehicle speedtracking strategy based on fuzzy logic arealso discussed. Besides, the capability of controlparameters self-compensation on-line makes it possible to compensate the wear of vehicle componentsand the variety of clutch true bite point during the long term test. Experimental results show thattherobot driver can be applicable to a wide variety of vehicles and the obtained results stay withina tolerance band of ± 2 km/h. Moreover the robot driver is able to control tested vehicles withgood repeatability and consistency; therefore, this methodpresents a solution to eliminate theuncertainty of emission test results by human drivers and to ensure the accuracy and reliability ofemission test results.展开更多
Aortopuhnonary window is a rare congenital cardiac malformation, which is previously repaired using cardiopulmonary bypass. However, some cases were reported to repair the aortopulmonary septal defect by transcathetcr...Aortopuhnonary window is a rare congenital cardiac malformation, which is previously repaired using cardiopulmonary bypass. However, some cases were reported to repair the aortopulmonary septal defect by transcathetcr closure. Here we present a 30 year-old woman with a 7-mm aortopulmonary window, who was successfully treated using a modified double-disk PmVSD occluder展开更多
Two popular traditional join algorithms and their parallel versions are introduced. When designing join algorithms in serial computing environment, decomposing inner relation is considered as the right direction to sa...Two popular traditional join algorithms and their parallel versions are introduced. When designing join algorithms in serial computing environment, decomposing inner relation is considered as the right direction to save disk I/Os. However, two different decomposition algorithms are compared, such as inner vs. outer decomposition first algorithms for tuple-based and block-based nested loop joins, showing that the proposed approach is 20% better than general approach. Also lemmas are proved, when we have to use the outer decomposition first parallel join algorithms.展开更多
Plasma-synthesized cobalt oxide supported on carbon has been analyzed for its use for electrocatalytic oxygen reduction reaction （ORR） in alkaline anion exchange membrane fuel cells （AEMFC）. This work presents the...Plasma-synthesized cobalt oxide supported on carbon has been analyzed for its use for electrocatalytic oxygen reduction reaction （ORR） in alkaline anion exchange membrane fuel cells （AEMFC）. This work presents the ORR activity in 0.1 mol L-1 KOH and 0.1 tool L-1 K2CO3 at 25 ℃. Cyclic voltammetry （CV） was used to determine the potentials at which the ORR occurs and to evaluate the stability of catalyst. Moreover, a rotating ring-disk electrode （RRDE） was used to investigate the activity of the catalysts and the formation of the by-product hydroperoxide anion （HO2-） as well as to identify the preferred pathway of the ORR. Calculated kinetic parameters for the ORR for the cobalt catalysts are shown in this work together with a comparison to a commercial platinum catalyst. However, the cobalt oxide produced more by-products which could lead to damage of the membrane in a fuel cell through a radical attack of the polymer backbone.展开更多
Objective： To observe the effect of electroacupuncture （EA） gait function, and expression levels of serum immunoglobul intervertebral disc herniation （LIDH）. at Huantiao （GB 30） and Weizhong （BL 40） on thigme...Objective： To observe the effect of electroacupuncture （EA） gait function, and expression levels of serum immunoglobul intervertebral disc herniation （LIDH）. at Huantiao （GB 30） and Weizhong （BL 40） on thigmesthesia, n G （IgG） and immunoglobulin M （IgM） in rabbits with lumbar Methods： Forty healthy New Zealand rabbits were randomly divided into a blank control group, a model group, an EA at acupoint group and an EA at non-acupoint group, with 10 rabbits in each group. The LIDH pathological model of rabbit was established using the self-made LIDH model maker. The thigmesthesia and gait function of rabbits were recorded by Siegal method. The serum IgG and IgM expression levels were detected by enzyme-linked immunosorbent assay. Results： EA at Huantiao （GB 30） and Weizhong （BL 40） could improve the clinical symptoms of thigmesthesia and gait function, and inhibit the expressions of serum IgG and IgM in the LIDH rabbits, which were significantly different compared with those in the model group and EA at non-acupoint group. Conclusion： EA at Huantiao （GB 30） and Weizhong （BL 40） can improve the clinical symptoms of LIDH rabbits, which is associated with inhibition of the serum IgG and IgM expressions and reduction of the immunoinflammatory factor release. This may be one of the mechanisms of EA at Huantiao （GB 301 and Weizhong[BL 407 in the treatment of LIDH.展开更多
Bodies freely falling in steady water or air are common scenes encountered in various scientific and engineering fields, including the flapping flight of birds and the reentry of a space shuttle. In this work, the fre...Bodies freely falling in steady water or air are common scenes encountered in various scientific and engineering fields, including the flapping flight of birds and the reentry of a space shuttle. In this work, the freely falling annular thin disks with small dimensionless moments of inertia f and Reynolds number Re are investigated experimentally in a water tank. We use stereo- scopic vision to record the position and orientation of the disks. The flow structure behind the disks is studied by applying fluorescent dye visualization and PIV method. Varying the geometry dimensionless parameter （the inner to outer diameter ratio η and I＊） of the disks reveals two new falling patterns. When ηcritl=0.6〈η〈ηcrit2=0.8, the disks show a random lateral vibration while falling. For high ηcrit2〉0.8, the circular vortex loops shed frequently from the disk, which causes a lengthways vibration superimposed onto straight vertical motion. We also observe another two falling patterns reported previously： hula-hoop and helical motion. By comparing the wake structure of the two motions, we find that the vortex layer twists more violently in the hula-hoop motion, which is the reason for the different trajectory between them. Further research on flow field reveals that the torque on the disk that causes the vibration is due to the formation, elongation and shedding of the vortex.展开更多
文摘A discontinuous Galerkin finite element method （DG-FEM） is developed for solving the axisymmetric Euler equations based on two-dimensional conservation laws. The method is used to simulate the unsteady-state underexpanded axisymmetric jet. Several flow property distributions along the jet axis, including density, pres- sure and Mach number are obtained and the qualitative flowfield structures of interest are well captured using the proposed method, including shock waves, slipstreams, traveling vortex ring and multiple Mach disks. Two Mach disk locations agree well with computational and experimental measurement results. It indicates that the method is robust and efficient for solving the unsteady-state underexpanded axisymmetric jet.
文摘A method for a vehicle durability emission test using a robot driver insteadof human drivers on the chassis dynamometer is presented. The system architecture of vehicledurability emission test cell, the road load simulation strategy and the tele-monitoring systembased on Browser/Client structure are described. Furthermore, the construction of the robot driver,vehicle performance self-learning algorithm, multi-mode vehicle control model and vehicle speedtracking strategy based on fuzzy logic arealso discussed. Besides, the capability of controlparameters self-compensation on-line makes it possible to compensate the wear of vehicle componentsand the variety of clutch true bite point during the long term test. Experimental results show thattherobot driver can be applicable to a wide variety of vehicles and the obtained results stay withina tolerance band of ± 2 km/h. Moreover the robot driver is able to control tested vehicles withgood repeatability and consistency; therefore, this methodpresents a solution to eliminate theuncertainty of emission test results by human drivers and to ensure the accuracy and reliability ofemission test results.
文摘Aortopuhnonary window is a rare congenital cardiac malformation, which is previously repaired using cardiopulmonary bypass. However, some cases were reported to repair the aortopulmonary septal defect by transcathetcr closure. Here we present a 30 year-old woman with a 7-mm aortopulmonary window, who was successfully treated using a modified double-disk PmVSD occluder
基金supported by the National Research Foundation (NRF) of Korea through contract N-14-NMIR06
文摘Two popular traditional join algorithms and their parallel versions are introduced. When designing join algorithms in serial computing environment, decomposing inner relation is considered as the right direction to save disk I/Os. However, two different decomposition algorithms are compared, such as inner vs. outer decomposition first algorithms for tuple-based and block-based nested loop joins, showing that the proposed approach is 20% better than general approach. Also lemmas are proved, when we have to use the outer decomposition first parallel join algorithms.
文摘Plasma-synthesized cobalt oxide supported on carbon has been analyzed for its use for electrocatalytic oxygen reduction reaction （ORR） in alkaline anion exchange membrane fuel cells （AEMFC）. This work presents the ORR activity in 0.1 mol L-1 KOH and 0.1 tool L-1 K2CO3 at 25 ℃. Cyclic voltammetry （CV） was used to determine the potentials at which the ORR occurs and to evaluate the stability of catalyst. Moreover, a rotating ring-disk electrode （RRDE） was used to investigate the activity of the catalysts and the formation of the by-product hydroperoxide anion （HO2-） as well as to identify the preferred pathway of the ORR. Calculated kinetic parameters for the ORR for the cobalt catalysts are shown in this work together with a comparison to a commercial platinum catalyst. However, the cobalt oxide produced more by-products which could lead to damage of the membrane in a fuel cell through a radical attack of the polymer backbone.
基金supported by Scientific Research Project of Hunan Provincial Administration of Traditional Chinese Medicine,No.201378~~
文摘Objective： To observe the effect of electroacupuncture （EA） gait function, and expression levels of serum immunoglobul intervertebral disc herniation （LIDH）. at Huantiao （GB 30） and Weizhong （BL 40） on thigmesthesia, n G （IgG） and immunoglobulin M （IgM） in rabbits with lumbar Methods： Forty healthy New Zealand rabbits were randomly divided into a blank control group, a model group, an EA at acupoint group and an EA at non-acupoint group, with 10 rabbits in each group. The LIDH pathological model of rabbit was established using the self-made LIDH model maker. The thigmesthesia and gait function of rabbits were recorded by Siegal method. The serum IgG and IgM expression levels were detected by enzyme-linked immunosorbent assay. Results： EA at Huantiao （GB 30） and Weizhong （BL 40） could improve the clinical symptoms of thigmesthesia and gait function, and inhibit the expressions of serum IgG and IgM in the LIDH rabbits, which were significantly different compared with those in the model group and EA at non-acupoint group. Conclusion： EA at Huantiao （GB 30） and Weizhong （BL 40） can improve the clinical symptoms of LIDH rabbits, which is associated with inhibition of the serum IgG and IgM expressions and reduction of the immunoinflammatory factor release. This may be one of the mechanisms of EA at Huantiao （GB 301 and Weizhong[BL 407 in the treatment of LIDH.
基金supported by the National Natural Science Foundation of China(Grant No.11672094)the Natural Science Foundation of Heilongjiang Province of China(Grant No.A201409)
文摘Bodies freely falling in steady water or air are common scenes encountered in various scientific and engineering fields, including the flapping flight of birds and the reentry of a space shuttle. In this work, the freely falling annular thin disks with small dimensionless moments of inertia f and Reynolds number Re are investigated experimentally in a water tank. We use stereo- scopic vision to record the position and orientation of the disks. The flow structure behind the disks is studied by applying fluorescent dye visualization and PIV method. Varying the geometry dimensionless parameter （the inner to outer diameter ratio η and I＊） of the disks reveals two new falling patterns. When ηcritl=0.6〈η〈ηcrit2=0.8, the disks show a random lateral vibration while falling. For high ηcrit2〉0.8, the circular vortex loops shed frequently from the disk, which causes a lengthways vibration superimposed onto straight vertical motion. We also observe another two falling patterns reported previously： hula-hoop and helical motion. By comparing the wake structure of the two motions, we find that the vortex layer twists more violently in the hula-hoop motion, which is the reason for the different trajectory between them. Further research on flow field reveals that the torque on the disk that causes the vibration is due to the formation, elongation and shedding of the vortex.
