The length of high-speed railway tunnel is an important factor affecting transient pressure of high-speed train.When the tunnel length is the most unfavourable,the transient pressure changes in the tunnel and on the s...The length of high-speed railway tunnel is an important factor affecting transient pressure of high-speed train.When the tunnel length is the most unfavourable,the transient pressure changes in the tunnel and on the surface of the train are the most severe,which may affect the safe operation of the train or damage the structure in the tunnel.Based on the three-dimensional,compressible,unsteady N-S equation and finite volume method,this paper uses the CFD numerical simulation method to study the change and amplitude distribution of the transient pressure on the train surface and the tunnel when a high-speed train passes through the most unfavourable length tunnel.A fast calculation method is proposed to save the cost of calculation;it has great applicability of pressure amplitude.The results show that the pressure distribution in the tunnel and on the surface of the train is affected by the train speed,the length of the train and the position of the measuring point.The minimum negative peak value in the tunnel appears at the position where the superposition phenomenon is the most severe,and the position will change with the speed of the train.There are two negative peak waveforms of the train surface pressure,and the first waveformn is greatly affected by the train speed.It improves a reference for studying the strength requirement of the most unfavourable length tunnels and trains,and ensures the safe operation of trains in tunnels of different lengths.展开更多
Background and Objectives: Risk-adapted therapy for children with HL is directed toward high survival, minimal toxicity and optimal quality of life, with long term follow up. We assess the impact of prognostic factors...Background and Objectives: Risk-adapted therapy for children with HL is directed toward high survival, minimal toxicity and optimal quality of life, with long term follow up. We assess the impact of prognostic factors associated with local treatment failure of pediatric HL patients with unfavorable criteria treated with combined modality: Alternating ABVD (Doxorubicin, Bleomycin, Vinblastine and Decarbazine) and COEP (Cyclophosphamide, Oncovin, Etoposide and Prednisone) chemotherapy and response-based, involved-field radiation for newly diagnosed unfavorable pediatric HL patients, also will detect toxicities and long-term complications observed in the patients. Methods: This prospective study was carried out from January 2010 to January 2018, with a median follow up of 74 months (range 8 - 103 months). 54 patients were eligible for this study stratified into two groups: intermediate risk (IR) and high-risk group (HR). Patients were treated with (4 - 6 cycles) and (6 - 8 cycles) respectively of alternating ABVD/COEP chemotherapy followed by involved-field radiation therapy (IFRT): 15 Gy for patients achieved complete response, and 25.5 Gy for those achieved a partial response. Results: 27 patients were IR and 27 patients were HR. There were 16 treatment failures;5 patients had progressive disease;and 11 patients had a relapse. 9 patients died from their disease progression. The 5-year overall survival (OS) and event-free survival (EFS) rates (±SE) were 81.8% ± 5.7% and 71.8% ± 6.2% respectively. Multivariate analysis revealed that the only independent factor for inferior OS was radiotherapy. Conclusion: Treatment results of unfavourable HL patients in our study are satisfactory for with IR group but not for HR group who needs intensification of therapy. Radiotherapy is considered as a cornerstone in the treatment of the patients with unfavourable criteria with better assessment of early responders needed by PET-CT to identify patients at risk for relapse.展开更多
基金This work was sponsored by the National Natural Science Foun-dation of China(Grant No.52002265)the China Postdoctoral Science Foundation(Grant No.2022M712930).
文摘The length of high-speed railway tunnel is an important factor affecting transient pressure of high-speed train.When the tunnel length is the most unfavourable,the transient pressure changes in the tunnel and on the surface of the train are the most severe,which may affect the safe operation of the train or damage the structure in the tunnel.Based on the three-dimensional,compressible,unsteady N-S equation and finite volume method,this paper uses the CFD numerical simulation method to study the change and amplitude distribution of the transient pressure on the train surface and the tunnel when a high-speed train passes through the most unfavourable length tunnel.A fast calculation method is proposed to save the cost of calculation;it has great applicability of pressure amplitude.The results show that the pressure distribution in the tunnel and on the surface of the train is affected by the train speed,the length of the train and the position of the measuring point.The minimum negative peak value in the tunnel appears at the position where the superposition phenomenon is the most severe,and the position will change with the speed of the train.There are two negative peak waveforms of the train surface pressure,and the first waveformn is greatly affected by the train speed.It improves a reference for studying the strength requirement of the most unfavourable length tunnels and trains,and ensures the safe operation of trains in tunnels of different lengths.
文摘Background and Objectives: Risk-adapted therapy for children with HL is directed toward high survival, minimal toxicity and optimal quality of life, with long term follow up. We assess the impact of prognostic factors associated with local treatment failure of pediatric HL patients with unfavorable criteria treated with combined modality: Alternating ABVD (Doxorubicin, Bleomycin, Vinblastine and Decarbazine) and COEP (Cyclophosphamide, Oncovin, Etoposide and Prednisone) chemotherapy and response-based, involved-field radiation for newly diagnosed unfavorable pediatric HL patients, also will detect toxicities and long-term complications observed in the patients. Methods: This prospective study was carried out from January 2010 to January 2018, with a median follow up of 74 months (range 8 - 103 months). 54 patients were eligible for this study stratified into two groups: intermediate risk (IR) and high-risk group (HR). Patients were treated with (4 - 6 cycles) and (6 - 8 cycles) respectively of alternating ABVD/COEP chemotherapy followed by involved-field radiation therapy (IFRT): 15 Gy for patients achieved complete response, and 25.5 Gy for those achieved a partial response. Results: 27 patients were IR and 27 patients were HR. There were 16 treatment failures;5 patients had progressive disease;and 11 patients had a relapse. 9 patients died from their disease progression. The 5-year overall survival (OS) and event-free survival (EFS) rates (±SE) were 81.8% ± 5.7% and 71.8% ± 6.2% respectively. Multivariate analysis revealed that the only independent factor for inferior OS was radiotherapy. Conclusion: Treatment results of unfavourable HL patients in our study are satisfactory for with IR group but not for HR group who needs intensification of therapy. Radiotherapy is considered as a cornerstone in the treatment of the patients with unfavourable criteria with better assessment of early responders needed by PET-CT to identify patients at risk for relapse.
