Flange joint part is the weak link of wind turbine tower.In view of the special structure,complex stress and easy failure of the connecting bolt of the wind turbine tower flange,the relationship between the external l...Flange joint part is the weak link of wind turbine tower.In view of the special structure,complex stress and easy failure of the connecting bolt of the wind turbine tower flange,the relationship between the external load of the tower section and the internal stress of the bolt is established by the finite element method,and the time series internal stress of the bolt is calculated by the Schmidt-Neuper algorithm.The S-N curve which is suitable for the connecting bolt material of the tower flange is selected by the GL2010 specification.On the basis of Miner’s fatigue cumulative damage theory and rain flow counting method,the fatigue strength of the whole ring bolt is roughly calculated,and the most dangerous part is determined.The axial symmetry model of screw connection is used for accurately calculating the fatigue cumulative damage of the bolt at the dangerous part.The results show that the fatigue life of the bolts in the most dangerous position can meet the requirements,the engineering algorithm has advantages in determining the dangerous part of the whole ring bolt,and the finite element method has high accuracy in predicting the fatigue life of the bolts in the dangerous part.The proposed method is feasible and effective in predicting the fatigue life of the flange joint bolts of the tower.展开更多
OBJECTIVE: To use evidence-based medicine to explore the efficacy of acupoint application(AA) for allergic rhinitis(AR) at different time points and its safety. METHODS: We searched 7 databases(Pub Med, Cochrane, Emba...OBJECTIVE: To use evidence-based medicine to explore the efficacy of acupoint application(AA) for allergic rhinitis(AR) at different time points and its safety. METHODS: We searched 7 databases(Pub Med, Cochrane, Embase, China National Knowledge Infrastructure, Wanfang Database, China Science and Technology Journal Database, and China Biology Medicine disc) as well as the international clinical trial registration platform from January 2010 to March 2020 for randomized controlled trials(RCTs) comparing the efficacy of AA versus placebo, Western Medicine or other alternative therapies on AR. Risk of bias was assessed according to the Cochrane handbook, and statistical analysis was performed using Rev Man 5.3. Outcomes included the total effective rate, recurrence rate, total nasal symptom score(TNSS), visual analogue scale(VAS), quality of life measured by the Rhinitis Quality of Life Questionnaire(RQLQ) or Short Form-36(SF-36), adverse events, and biomarkers including immunoglobulin E(Ig E), peripheral blood eosinophil count(EOS), interleukin-4(IL-4), and interferon gamma(INF-γ). RESULTS: Twenty-eight RCTs involving 3282 participants were included. The short-term and long-term efficacy of AA was significantly better than placebo, including better total effective rate [RR: 3.05, 95%CI(1.84, 5.07), after treatment;RR: 9.29, 95%CI(2.57, 33.66), at 6 months], lower recurrence rate [RR: 0.55, 95%CI(0.45, 0.66), at 6 months;RR: 0.65, 95%CI(0.57, 0.74), at 1 year], lower TNSS [MD:-3.09, 95%CI(-3.58,-2.61), after treatment], and lower RQLQ [MD:-14.79, 95%CI(-21.49,-8.10), after treatment;MD:-11.92, 95%CI(-17.40,-6.45), at 4-6 months]. Compared with Western Medicine, AA had better long-term total effective rate [RR: 1.33, 95%CI(1.05, 1.69), at 3 months;RR: 1.49, 95%CI 1.22 to 1.81, at 1 year) and lower recurrence rate [RR: 0.48, 95%CI(0.39, 0.58), at 6 months;RR: 0.45, 95%CI(0.33, 0.60), at 1 year]. AA had better long-term total effective rate versus acupuncture [RR: 2.06, 95% CI(1.28, 3.31), at 1 year] or oral Chinese medicine [RR: 1.21, 95% CI(1.09, 1.34), ≥ 6 months]. Both AA and Western Medicine can reduce serum levels of Ig E, EOS, and IL-4 after treatment. The main adverse event of AA was local skin reaction without systemic side effects. CONCLUSIONS: The short-term(within one month) and long-term(at 3 months, 6 months and 1 year) efficacy of acupoint application on AR was better than that of placebo. The long-term efficacy of acupoint application was superior to that of Western Medicine(at 3 months, 6 months and 1 year), oral Chinese medicine(at more than 6 months) and acupuncture(at 1 year). AA can reduce serum Ig E, EOS, and IL-4 level of AR patients in a short run. Acupoint application is safe, but severe skin reactions can reduce patient compliance.展开更多
基金the Special Research Fund for the Natural Science Foundation of Inner Mongolia Autonomous Region(No.2019MS05070)。
文摘Flange joint part is the weak link of wind turbine tower.In view of the special structure,complex stress and easy failure of the connecting bolt of the wind turbine tower flange,the relationship between the external load of the tower section and the internal stress of the bolt is established by the finite element method,and the time series internal stress of the bolt is calculated by the Schmidt-Neuper algorithm.The S-N curve which is suitable for the connecting bolt material of the tower flange is selected by the GL2010 specification.On the basis of Miner’s fatigue cumulative damage theory and rain flow counting method,the fatigue strength of the whole ring bolt is roughly calculated,and the most dangerous part is determined.The axial symmetry model of screw connection is used for accurately calculating the fatigue cumulative damage of the bolt at the dangerous part.The results show that the fatigue life of the bolts in the most dangerous position can meet the requirements,the engineering algorithm has advantages in determining the dangerous part of the whole ring bolt,and the finite element method has high accuracy in predicting the fatigue life of the bolts in the dangerous part.The proposed method is feasible and effective in predicting the fatigue life of the flange joint bolts of the tower.
基金Supported by the Key Science and Technology Projects of Zhejiang Province:Research and Application of Key Techniques for Prevention and Treatment of Allergic Diseases of the Respiratory Tract by Summer Treatment of Winter Disease of Acupoint Application (No. 2014C03046-2)。
文摘OBJECTIVE: To use evidence-based medicine to explore the efficacy of acupoint application(AA) for allergic rhinitis(AR) at different time points and its safety. METHODS: We searched 7 databases(Pub Med, Cochrane, Embase, China National Knowledge Infrastructure, Wanfang Database, China Science and Technology Journal Database, and China Biology Medicine disc) as well as the international clinical trial registration platform from January 2010 to March 2020 for randomized controlled trials(RCTs) comparing the efficacy of AA versus placebo, Western Medicine or other alternative therapies on AR. Risk of bias was assessed according to the Cochrane handbook, and statistical analysis was performed using Rev Man 5.3. Outcomes included the total effective rate, recurrence rate, total nasal symptom score(TNSS), visual analogue scale(VAS), quality of life measured by the Rhinitis Quality of Life Questionnaire(RQLQ) or Short Form-36(SF-36), adverse events, and biomarkers including immunoglobulin E(Ig E), peripheral blood eosinophil count(EOS), interleukin-4(IL-4), and interferon gamma(INF-γ). RESULTS: Twenty-eight RCTs involving 3282 participants were included. The short-term and long-term efficacy of AA was significantly better than placebo, including better total effective rate [RR: 3.05, 95%CI(1.84, 5.07), after treatment;RR: 9.29, 95%CI(2.57, 33.66), at 6 months], lower recurrence rate [RR: 0.55, 95%CI(0.45, 0.66), at 6 months;RR: 0.65, 95%CI(0.57, 0.74), at 1 year], lower TNSS [MD:-3.09, 95%CI(-3.58,-2.61), after treatment], and lower RQLQ [MD:-14.79, 95%CI(-21.49,-8.10), after treatment;MD:-11.92, 95%CI(-17.40,-6.45), at 4-6 months]. Compared with Western Medicine, AA had better long-term total effective rate [RR: 1.33, 95%CI(1.05, 1.69), at 3 months;RR: 1.49, 95%CI 1.22 to 1.81, at 1 year) and lower recurrence rate [RR: 0.48, 95%CI(0.39, 0.58), at 6 months;RR: 0.45, 95%CI(0.33, 0.60), at 1 year]. AA had better long-term total effective rate versus acupuncture [RR: 2.06, 95% CI(1.28, 3.31), at 1 year] or oral Chinese medicine [RR: 1.21, 95% CI(1.09, 1.34), ≥ 6 months]. Both AA and Western Medicine can reduce serum levels of Ig E, EOS, and IL-4 after treatment. The main adverse event of AA was local skin reaction without systemic side effects. CONCLUSIONS: The short-term(within one month) and long-term(at 3 months, 6 months and 1 year) efficacy of acupoint application on AR was better than that of placebo. The long-term efficacy of acupoint application was superior to that of Western Medicine(at 3 months, 6 months and 1 year), oral Chinese medicine(at more than 6 months) and acupuncture(at 1 year). AA can reduce serum Ig E, EOS, and IL-4 level of AR patients in a short run. Acupoint application is safe, but severe skin reactions can reduce patient compliance.
