Purpose： This study was designed to characterize and compare the vertical（kvert） and leg（kleg） stiffness measured during running in two different footwear conditions on negative, level, and positive slopes, using...Purpose： This study was designed to characterize and compare the vertical（kvert） and leg（kleg） stiffness measured during running in two different footwear conditions on negative, level, and positive slopes, using kinematic data only.Methods： Fourteen male recreational runners（age 23.4 4.4 years, height 177.5 5.2 cm, and body mass 69.5 5.3 kg） were tested on 2separate days within 1 week. At each session, subjects ran seven 5-min trials on a treadmill at 10 km/h, interspersed with 5 min of sitting passive recovery. Each trial was performed on a different slope gradient, ranging from 8%（downhill） to t8%（uphill）, assigned in a random order.Furthermore, each subject ran one 5-min trial wearing minimal shoes（MS） and the subsequent trial wearing traditional shoes（TS） in a counterbalanced randomized order ensuring that each slope was ran once in MS and once in TS. Kinematic data were collected using a photocell measuring system and high-speed video camera, with kvertand klegstiffness being calculated from these data.Results： Leg compression, contact times, and vertical displacement of the center of mass during running were significantly smaller in MS compared to TS across all slopes. In the two footwear conditions, step frequency significantly increased with a（positive） increase in slope.Kinematic analyses indicated that klegwas greater when running in MS than TS and this between-footwear difference remained similar across slopes. On the contrary, kvertdid not change on the basis of footwear, but increased with positive increases in slope.Conclusion： This study showed that kvertand klegduring running respond differently to change in footwear and/or slope. These two stiffness measures can hence provide a unique insight on the biomechanical adaptations of running under varying conditions and their respective quantification may assist in furthering our understanding of training, performance, and/or injury in this sport.展开更多
This paper deals with transformation procedures for observed GPS data from the world geodetic system WGS84 into the national geodetic grid datum SUTCN （system of united trigonometric cadaster network） and Baa（the B...This paper deals with transformation procedures for observed GPS data from the world geodetic system WGS84 into the national geodetic grid datum SUTCN （system of united trigonometric cadaster network） and Baa（the Baltic Sea after adjustment）.Transformation from WGS84 into SUTCN is performed most frequently by means of the 7element Helmert transformation with three identical points.Geodetic network was adjusted by two ways.展开更多
The coordinates of the marked points of joints and the changes of foot force in the human walk motion are obtained with systems of motion image acquisition and force measuring.The effects of kinematics and dynamics on...The coordinates of the marked points of joints and the changes of foot force in the human walk motion are obtained with systems of motion image acquisition and force measuring.The effects of kinematics and dynamics on the human lower limb in different loads(0,10,20,30 kg) and walking speeds(0.8,1.3,1.7 m/s) have been investigated using the human dynamics model,.The results were as follows.First,with the increasing load,the dorsiflexion angle of ankle joint increased during the procedure of toe-off,the range of motion of the knee joint decreased,the flexion angle of the hip joint increased,and oppositely,the extension angle of the hip joint decreased.Second,with the increasing speed,the range of motion of the ankle joint,the maximum flexion angle of the knee joint,the flexion angle,extension angle of the hip joint and the range of motion of hip joint increased.Finally,the torque and power of the ankle joint,the knee joint and the hip joint increased with the increasing speed and load.The results can provide an important basis for the mechanism design of lower limb power-assisted exoskeleton.展开更多
The sloshing flows in a LNG cargo tank model （1/50 scale） of a ship are measured by an embedded pano- ramicPIV system. The measurement system consists of a Nd-Yag laser（120mJ, 15Hz）, two cameras（lk x lk） and a h...The sloshing flows in a LNG cargo tank model （1/50 scale） of a ship are measured by an embedded pano- ramicPIV system. The measurement system consists of a Nd-Yag laser（120mJ, 15Hz）, two cameras（lk x lk） and a host computer. Four experimental cases were tested for the tank model, in which swaying motions are made by a 6 DOF-motion platform. The amplitudes of swaying are 9.76mm and 29.29mm, and the swaying frequencies are 0.633Hz and 0.828Hz. The measurement regions are the vertical plane 50ram away from the front wall of the tank where a pump tower is installed. It was verified that the flow patterns of the sloshing are similar to each other when the swaying amplitudes are similar.展开更多
基金supported by the University of Franche Comte' (France) and the Exercise, Performance, Health, and Innovation platform of Besancon
文摘Purpose： This study was designed to characterize and compare the vertical（kvert） and leg（kleg） stiffness measured during running in two different footwear conditions on negative, level, and positive slopes, using kinematic data only.Methods： Fourteen male recreational runners（age 23.4 4.4 years, height 177.5 5.2 cm, and body mass 69.5 5.3 kg） were tested on 2separate days within 1 week. At each session, subjects ran seven 5-min trials on a treadmill at 10 km/h, interspersed with 5 min of sitting passive recovery. Each trial was performed on a different slope gradient, ranging from 8%（downhill） to t8%（uphill）, assigned in a random order.Furthermore, each subject ran one 5-min trial wearing minimal shoes（MS） and the subsequent trial wearing traditional shoes（TS） in a counterbalanced randomized order ensuring that each slope was ran once in MS and once in TS. Kinematic data were collected using a photocell measuring system and high-speed video camera, with kvertand klegstiffness being calculated from these data.Results： Leg compression, contact times, and vertical displacement of the center of mass during running were significantly smaller in MS compared to TS across all slopes. In the two footwear conditions, step frequency significantly increased with a（positive） increase in slope.Kinematic analyses indicated that klegwas greater when running in MS than TS and this between-footwear difference remained similar across slopes. On the contrary, kvertdid not change on the basis of footwear, but increased with positive increases in slope.Conclusion： This study showed that kvertand klegduring running respond differently to change in footwear and/or slope. These two stiffness measures can hence provide a unique insight on the biomechanical adaptations of running under varying conditions and their respective quantification may assist in furthering our understanding of training, performance, and/or injury in this sport.
文摘This paper deals with transformation procedures for observed GPS data from the world geodetic system WGS84 into the national geodetic grid datum SUTCN （system of united trigonometric cadaster network） and Baa（the Baltic Sea after adjustment）.Transformation from WGS84 into SUTCN is performed most frequently by means of the 7element Helmert transformation with three identical points.Geodetic network was adjusted by two ways.
文摘The coordinates of the marked points of joints and the changes of foot force in the human walk motion are obtained with systems of motion image acquisition and force measuring.The effects of kinematics and dynamics on the human lower limb in different loads(0,10,20,30 kg) and walking speeds(0.8,1.3,1.7 m/s) have been investigated using the human dynamics model,.The results were as follows.First,with the increasing load,the dorsiflexion angle of ankle joint increased during the procedure of toe-off,the range of motion of the knee joint decreased,the flexion angle of the hip joint increased,and oppositely,the extension angle of the hip joint decreased.Second,with the increasing speed,the range of motion of the ankle joint,the maximum flexion angle of the knee joint,the flexion angle,extension angle of the hip joint and the range of motion of hip joint increased.Finally,the torque and power of the ankle joint,the knee joint and the hip joint increased with the increasing speed and load.The results can provide an important basis for the mechanism design of lower limb power-assisted exoskeleton.
基金supported by the National Research Foundation of Korea(NRF) grant funded by the Korea government(MEST) (No. 2008-0060153)
文摘The sloshing flows in a LNG cargo tank model （1/50 scale） of a ship are measured by an embedded pano- ramicPIV system. The measurement system consists of a Nd-Yag laser（120mJ, 15Hz）, two cameras（lk x lk） and a host computer. Four experimental cases were tested for the tank model, in which swaying motions are made by a 6 DOF-motion platform. The amplitudes of swaying are 9.76mm and 29.29mm, and the swaying frequencies are 0.633Hz and 0.828Hz. The measurement regions are the vertical plane 50ram away from the front wall of the tank where a pump tower is installed. It was verified that the flow patterns of the sloshing are similar to each other when the swaying amplitudes are similar.
