Experimental research and numerical analysis were applied to study the ultimate load capacity(ULC) and reinforcement of circular-hollow-section N-joint.Four specimens were tested under static load.The ULC of each spec...Experimental research and numerical analysis were applied to study the ultimate load capacity(ULC) and reinforcement of circular-hollow-section N-joint.Four specimens were tested under static load.The ULC of each specimen was obtained and the detailed failure conditions were discussed.Based on the results, both welding a plate on the chord member and filling concrete in the chord member are effective to reinforce the N-joint, but it is suggested that these two methods should not be applied simultaneously.Mo...展开更多
Objective The objective of this study was to analyze the status of the clinical application of Yufeng Ningxin(YFNX)preparations and systematically evaluate their efficacy and safety in the treatment of cardiovascular ...Objective The objective of this study was to analyze the status of the clinical application of Yufeng Ningxin(YFNX)preparations and systematically evaluate their efficacy and safety in the treatment of cardiovascular and cerebrovascular diseases.Methods Through searching databases of China National Knowledge Infrastructure,Wanfang,SinoMed,VIP,PubMed,Embase,and the Cochrane Library,the literature of clinical research on YFNX preparations in treating malignant tumors of cardiovascular and cerebrovascular diseases from the establishment of the databases to February 2021 was collected.The clinical randomized controlled trials and case-control studies of cardiovascular and cerebrovascular diseases treated with these preparations were analyzed.Two reviewers independently screened literature,extracted data,and assessed the risk of bias in the included studies,and meta analysis was performed by using ReMan 5.3 software to analyze the eficacy and safety of YFNX preparations in the treatment of cardiovascular and cerebrovascular diseases.Results A total of 29 clinical studies were finally included.The dosage forms were dropping plls,tablets,capsules,and granules.The preparations were used for the treatment of coronary heart disease,hypertension,neuropathic headache,etc.This study systematically evaluated the efficacy and safety of YFNX preparations in the treatment of coronary heart disease,hypertension,and nervous headache.A total of 1,162 cases were included in 13 studies,582 cases of the YFNX preparation group and 580 cases of the Western medicine group.The results of meta-analysis showed that the clinical efficacy of YFNX preparations combined with the Western medicine group in the treatment of coronary heart disease and hypertension,improving electrocardiogram and reducing the frequency and duration of angina attacks,was better than that of the simple Western medicine group,and the difference was statistically significant.Conclusion YFNX preparations are effective for coronary heart disease,hypertension,and neuropathic headache,and the adverse reactions are few.展开更多
This paper presents a detailed investigation, via field experiment, into the mechanism of high-order polygonal wear of wheels of a new type of high-speed train. The investigation was carried out during the performance...This paper presents a detailed investigation, via field experiment, into the mechanism of high-order polygonal wear of wheels of a new type of high-speed train. The investigation was carried out during the performance acceptance test of the train and its initial commercial operation. The investigation covered the performance acceptance test of 150 000 km and the commercial operation of about 150 000 km. In the performance acceptance test of the first stage of about 70 000 km, at 200-250 km/h with full loading and sometimes overloading by 30%, the serious polygonal wear of 23-order took place on all the wheels of the train, and was measured and analyzed in detail. All the potygonized wheels were re-profiled because the polygonal wear had caused strong vibration and damage to the train parts. After re-profiling, the vibration of the train and track and the wear status of the wheels were measured and analyzed at different test mileages according to the polygonal wear situation of the wheels. The measured vibration of the train includes the accelerations at different positions of a motor car and a trail car. The vibration modes of the key parts of the bogies of the two cars were calculated. Meanwhile, the track resonant frequencies were investigated at the site. The purpose of the above tests and analysis is try to find the frequency of work mode matching the passing frequency of the high-order wheel polygon. The present investigation shows that one of the working models causes the formation and development of the high-order wheel polygonal wear. The growth of this wear was effectively reduced through the frequent changing of the running speed of the train operating on the way back and forth every day.展开更多
基金Supported by National Natural Science Foundation of China (No.50608054)
文摘Experimental research and numerical analysis were applied to study the ultimate load capacity(ULC) and reinforcement of circular-hollow-section N-joint.Four specimens were tested under static load.The ULC of each specimen was obtained and the detailed failure conditions were discussed.Based on the results, both welding a plate on the chord member and filling concrete in the chord member are effective to reinforce the N-joint, but it is suggested that these two methods should not be applied simultaneously.Mo...
基金supported by Tianjin Municipal Education Commission Scientifc Research Program(2021KJ170).
文摘Objective The objective of this study was to analyze the status of the clinical application of Yufeng Ningxin(YFNX)preparations and systematically evaluate their efficacy and safety in the treatment of cardiovascular and cerebrovascular diseases.Methods Through searching databases of China National Knowledge Infrastructure,Wanfang,SinoMed,VIP,PubMed,Embase,and the Cochrane Library,the literature of clinical research on YFNX preparations in treating malignant tumors of cardiovascular and cerebrovascular diseases from the establishment of the databases to February 2021 was collected.The clinical randomized controlled trials and case-control studies of cardiovascular and cerebrovascular diseases treated with these preparations were analyzed.Two reviewers independently screened literature,extracted data,and assessed the risk of bias in the included studies,and meta analysis was performed by using ReMan 5.3 software to analyze the eficacy and safety of YFNX preparations in the treatment of cardiovascular and cerebrovascular diseases.Results A total of 29 clinical studies were finally included.The dosage forms were dropping plls,tablets,capsules,and granules.The preparations were used for the treatment of coronary heart disease,hypertension,neuropathic headache,etc.This study systematically evaluated the efficacy and safety of YFNX preparations in the treatment of coronary heart disease,hypertension,and nervous headache.A total of 1,162 cases were included in 13 studies,582 cases of the YFNX preparation group and 580 cases of the Western medicine group.The results of meta-analysis showed that the clinical efficacy of YFNX preparations combined with the Western medicine group in the treatment of coronary heart disease and hypertension,improving electrocardiogram and reducing the frequency and duration of angina attacks,was better than that of the simple Western medicine group,and the difference was statistically significant.Conclusion YFNX preparations are effective for coronary heart disease,hypertension,and neuropathic headache,and the adverse reactions are few.
基金Project supported by the National Natural Science Foundation of China （No. U 1134202）
文摘This paper presents a detailed investigation, via field experiment, into the mechanism of high-order polygonal wear of wheels of a new type of high-speed train. The investigation was carried out during the performance acceptance test of the train and its initial commercial operation. The investigation covered the performance acceptance test of 150 000 km and the commercial operation of about 150 000 km. In the performance acceptance test of the first stage of about 70 000 km, at 200-250 km/h with full loading and sometimes overloading by 30%, the serious polygonal wear of 23-order took place on all the wheels of the train, and was measured and analyzed in detail. All the potygonized wheels were re-profiled because the polygonal wear had caused strong vibration and damage to the train parts. After re-profiling, the vibration of the train and track and the wear status of the wheels were measured and analyzed at different test mileages according to the polygonal wear situation of the wheels. The measured vibration of the train includes the accelerations at different positions of a motor car and a trail car. The vibration modes of the key parts of the bogies of the two cars were calculated. Meanwhile, the track resonant frequencies were investigated at the site. The purpose of the above tests and analysis is try to find the frequency of work mode matching the passing frequency of the high-order wheel polygon. The present investigation shows that one of the working models causes the formation and development of the high-order wheel polygonal wear. The growth of this wear was effectively reduced through the frequent changing of the running speed of the train operating on the way back and forth every day.
