Purpose–Type-120 relief valves are critical components of locomotive braking systems,and they rapidly discharge the air pressure during brake release to enable swift pressure relief.In order to develop type-120 relie...Purpose–Type-120 relief valves are critical components of locomotive braking systems,and they rapidly discharge the air pressure during brake release to enable swift pressure relief.In order to develop type-120 relief valve rubber diaphragms with long life and high performance,the damaged faulty samples were analyzed and studied.Design/methodology/approach–Finite element analysis(FEA)was used to investigate the stress distribution and failure mechanism of the rubber diaphragms within the type-120 relief valves under dynamic loading conditions.The Ogden hyperelastic constitutive model was used to fit the diaphragm data obtained from the uniaxial tensile tests,and its suitability for the modeling of large deformations was confirmed.Findings–The FEA results indicated that,when the rubber diaphragms reached their maximum deformation,the peak stress on their upper surfaces was 5.44 MPa.Thus,this region is highly susceptible to fatigue damage.The service life of the rubber diaphragms could be extended by using rubber compounds with high tensile moduli or a fabric-reinforced rubber diaphragm.Originality/value–This study provides valuable data and experience for the development of the rubber diaphragms in the type-120 valves and other long-life rubber products in the railway field.展开更多
目的探讨新诊断2型糖尿病(type 2 diabetes mellitus,T2DM)患者基线血钾水平对胰岛素抵抗指数(ho⁃meostasis model assessment for insulin resistance,HOMA-IR)及处置指数(disposition index at 120 minutes,DI120)的影响,分析血钾与...目的探讨新诊断2型糖尿病(type 2 diabetes mellitus,T2DM)患者基线血钾水平对胰岛素抵抗指数(ho⁃meostasis model assessment for insulin resistance,HOMA-IR)及处置指数(disposition index at 120 minutes,DI120)的影响,分析血钾与糖代谢指标的相关性。方法回顾性选取2024年1—12月湛江南油医院收治的新诊断86例T2DM患者的临床资料。根据基线血钾水平分为两组:血钾正常组(3.5~5.0 mmol/L,n=30)和血钾异常组(<3.5 mmol/L或>5.0 mmol/L,n=56)。收集基线特征、电解质、糖代谢及肾功能指标进行单因素分析,以连续变量形式纳入多因素Logistic回归分析血钾水平对HOMA-IR和DI120的影响。结果血钾异常组与血钾正常组的HOMA-IR、DI120、eGFR水平对比,差异均有统计学意义(P均<0.05)。多因素Logistic回归分析结果显示,HOMA-IR、eGFR和DI120是血钾异常的独立影响因素(P均<0.05)。结论新诊断T2DM患者中,血钾异常是胰岛素抵抗加重和早期胰岛素分泌功能受损的独立危险因素。维持血钾稳态,特别是预防和纠正血钾异常,可能成为改善患者糖代谢状况的新靶点。展开更多
基金supported by the Science and Technology Research and Development Plan of the China State Railway Group Company Limited(Grant No.N2023J053).
文摘Purpose–Type-120 relief valves are critical components of locomotive braking systems,and they rapidly discharge the air pressure during brake release to enable swift pressure relief.In order to develop type-120 relief valve rubber diaphragms with long life and high performance,the damaged faulty samples were analyzed and studied.Design/methodology/approach–Finite element analysis(FEA)was used to investigate the stress distribution and failure mechanism of the rubber diaphragms within the type-120 relief valves under dynamic loading conditions.The Ogden hyperelastic constitutive model was used to fit the diaphragm data obtained from the uniaxial tensile tests,and its suitability for the modeling of large deformations was confirmed.Findings–The FEA results indicated that,when the rubber diaphragms reached their maximum deformation,the peak stress on their upper surfaces was 5.44 MPa.Thus,this region is highly susceptible to fatigue damage.The service life of the rubber diaphragms could be extended by using rubber compounds with high tensile moduli or a fabric-reinforced rubber diaphragm.Originality/value–This study provides valuable data and experience for the development of the rubber diaphragms in the type-120 valves and other long-life rubber products in the railway field.
文摘目的探讨新诊断2型糖尿病(type 2 diabetes mellitus,T2DM)患者基线血钾水平对胰岛素抵抗指数(ho⁃meostasis model assessment for insulin resistance,HOMA-IR)及处置指数(disposition index at 120 minutes,DI120)的影响,分析血钾与糖代谢指标的相关性。方法回顾性选取2024年1—12月湛江南油医院收治的新诊断86例T2DM患者的临床资料。根据基线血钾水平分为两组:血钾正常组(3.5~5.0 mmol/L,n=30)和血钾异常组(<3.5 mmol/L或>5.0 mmol/L,n=56)。收集基线特征、电解质、糖代谢及肾功能指标进行单因素分析,以连续变量形式纳入多因素Logistic回归分析血钾水平对HOMA-IR和DI120的影响。结果血钾异常组与血钾正常组的HOMA-IR、DI120、eGFR水平对比,差异均有统计学意义(P均<0.05)。多因素Logistic回归分析结果显示,HOMA-IR、eGFR和DI120是血钾异常的独立影响因素(P均<0.05)。结论新诊断T2DM患者中,血钾异常是胰岛素抵抗加重和早期胰岛素分泌功能受损的独立危险因素。维持血钾稳态,特别是预防和纠正血钾异常,可能成为改善患者糖代谢状况的新靶点。
