The criteria for evaluation of train derailment were studied. The worldwide commonly used evaluation criteria for wheel derailment were summarized and their main problems were pointed out. The mechanism of train derai...The criteria for evaluation of train derailment were studied. The worldwide commonly used evaluation criteria for wheel derailment were summarized and their main problems were pointed out. The mechanism of train derailment was expounded on the basis of system dynamics stability concept. And the energy increment criteria were proposed to evaluate train derailment. By applying the criteria, the calculated results concerning 6 cases of freight train derailment on tangent railway line and 6 cases of freight train derailment on bridge were obtained, which are all in agreement with the practical situation. The safety, comfort and stability results concerning 3 cases of freight train running on bridge were analyzed. In addition, the running speed limits of freight train on the Yanconggou and Donggou bridge in the Beijing-Tonghua railway line of 50km/h and 60km/h, respectively, were proposed. And the running speed of freight train on the Nanjing Yangtze River Bridge can reach 70km/h.展开更多
Back-propagation artificial neural network (BPANN) is used in ball backward spinning in order to form thin-walled tubular parts with longitudinal inner ribs. By selecting the process parameters which have a great infl...Back-propagation artificial neural network (BPANN) is used in ball backward spinning in order to form thin-walled tubular parts with longitudinal inner ribs. By selecting the process parameters which have a great influence on the height of inner ribs as well as fish scale on the surface of the spun part, a BPANN of 3-8-1 structure is established for predicting the height of inner rib and recognizing the fish scale defect. Experiments data have proved that the average relative error between the measured value and the predicted value of the height of inner rib is not more than 5%. It is evident that BPANN can not only predict the height of inner ribs of the spun part accurately, but recognize and prevent the occurrence of the quality defect of fish scale successfully, and combining BPANN with the ball backward spinning is essential to obtain the desired spun part.展开更多
Purpose： Tibial fracture is the most common long bone fracture. Distal third tibial fractures are chal- lenging though open reduction and plating can result in anatomical reduction and rigid fixation. This paper aime...Purpose： Tibial fracture is the most common long bone fracture. Distal third tibial fractures are chal- lenging though open reduction and plating can result in anatomical reduction and rigid fixation. This paper aimed to evaluate and compare the results of medial and lateral locking compression plates for distal third tibial fractures. Methods： This prospective clinical study involved 36 patients with distal tibial fractures admitted in Department of Orthopaedics, Sawai Mansingh Medical College ＆ Affiliated Hospital, Jaipur, India, from June 2011 to May 2012, including 29 closed fractures and 7 open fractures at the mean age of 38.9 years. Thirty-six patients were divided equally into two groups based on treatment method, including medial plating group （18 patients） and lateral plating group （18 patients）. They were followed up for at least 5 months after discharge. The functional outcomes were evaluated using Tenny and Wiss clinical assess- ment criteria. Results： Malunion was found in 3 cases of medial plating group and in 1 case of lateral plating group. In the medial plating group, there were 5 cases of superficial infections, 1 deep infection, 1 nonunion and 3 wound dehiscence. In the lateral plating group, there was 1 case of superficial infections, 1 deep infection and 1 nonunion, in the lateral plating group, 4 patients reported feeling the plates and screws but none of them asked to remove the hardware. In the medial plating group, 9 patients reported symptomatic hardware problems and 7 asked to remove the hardware. The number of cases graded as excellent/good/ fair was 1/8/7 in the medial plating group and 3/7/7 in the lateral plating group respectively. In the medial plating group, the final range of motion was 17.2° in ankle dorsiflexion and 30.7° in ankle plantar flexion. In the lateral plating group, the final range of motion was 19° in ankle dorsiflexion and 34.2° in ankle plantar flexion. Conclusion： Lateral plating of distal tibia is safe and feasible, which can provide biological fixation and prevent the soft tissue complications associated with medial plating.展开更多
基金Project(50078006) supported by the National Natural Science Foundation of China project ( 2001G029+1 种基金 2003G043)supported by the Foundation of the Science and Technology Section of the Railway Bureau of China project (2001053300
文摘The criteria for evaluation of train derailment were studied. The worldwide commonly used evaluation criteria for wheel derailment were summarized and their main problems were pointed out. The mechanism of train derailment was expounded on the basis of system dynamics stability concept. And the energy increment criteria were proposed to evaluate train derailment. By applying the criteria, the calculated results concerning 6 cases of freight train derailment on tangent railway line and 6 cases of freight train derailment on bridge were obtained, which are all in agreement with the practical situation. The safety, comfort and stability results concerning 3 cases of freight train running on bridge were analyzed. In addition, the running speed limits of freight train on the Yanconggou and Donggou bridge in the Beijing-Tonghua railway line of 50km/h and 60km/h, respectively, were proposed. And the running speed of freight train on the Nanjing Yangtze River Bridge can reach 70km/h.
文摘Back-propagation artificial neural network (BPANN) is used in ball backward spinning in order to form thin-walled tubular parts with longitudinal inner ribs. By selecting the process parameters which have a great influence on the height of inner ribs as well as fish scale on the surface of the spun part, a BPANN of 3-8-1 structure is established for predicting the height of inner rib and recognizing the fish scale defect. Experiments data have proved that the average relative error between the measured value and the predicted value of the height of inner rib is not more than 5%. It is evident that BPANN can not only predict the height of inner ribs of the spun part accurately, but recognize and prevent the occurrence of the quality defect of fish scale successfully, and combining BPANN with the ball backward spinning is essential to obtain the desired spun part.
文摘Purpose： Tibial fracture is the most common long bone fracture. Distal third tibial fractures are chal- lenging though open reduction and plating can result in anatomical reduction and rigid fixation. This paper aimed to evaluate and compare the results of medial and lateral locking compression plates for distal third tibial fractures. Methods： This prospective clinical study involved 36 patients with distal tibial fractures admitted in Department of Orthopaedics, Sawai Mansingh Medical College ＆ Affiliated Hospital, Jaipur, India, from June 2011 to May 2012, including 29 closed fractures and 7 open fractures at the mean age of 38.9 years. Thirty-six patients were divided equally into two groups based on treatment method, including medial plating group （18 patients） and lateral plating group （18 patients）. They were followed up for at least 5 months after discharge. The functional outcomes were evaluated using Tenny and Wiss clinical assess- ment criteria. Results： Malunion was found in 3 cases of medial plating group and in 1 case of lateral plating group. In the medial plating group, there were 5 cases of superficial infections, 1 deep infection, 1 nonunion and 3 wound dehiscence. In the lateral plating group, there was 1 case of superficial infections, 1 deep infection and 1 nonunion, in the lateral plating group, 4 patients reported feeling the plates and screws but none of them asked to remove the hardware. In the medial plating group, 9 patients reported symptomatic hardware problems and 7 asked to remove the hardware. The number of cases graded as excellent/good/ fair was 1/8/7 in the medial plating group and 3/7/7 in the lateral plating group respectively. In the medial plating group, the final range of motion was 17.2° in ankle dorsiflexion and 30.7° in ankle plantar flexion. In the lateral plating group, the final range of motion was 19° in ankle dorsiflexion and 34.2° in ankle plantar flexion. Conclusion： Lateral plating of distal tibia is safe and feasible, which can provide biological fixation and prevent the soft tissue complications associated with medial plating.
