To ensure the safe performance of deep-sea mining vehicles(DSMVs),it is necessary to study the mechanical characteristics of the interaction between the seabed soil and the track plate.The rotation and digging motions...To ensure the safe performance of deep-sea mining vehicles(DSMVs),it is necessary to study the mechanical characteristics of the interaction between the seabed soil and the track plate.The rotation and digging motions of the track plate are important links in the contact between the driving mechanism of the DSMV and seabed soil.In this study,a numerical simulation is conducted using the coupled Eulerian–Lagrangian(CEL)large deformation numerical method to investigate the interaction between the track plate of the DSMV and the seabed soil under two working conditions:rotating condition and digging condition.First,a soil numerical model is established based on the elastoplastic mechanical characterization using the basic physical and mechanical properties of the seabed soil obtained by in situ sampling.Subsequently,the soil disturbance mechanism and the dynamic mechanical response of the track plate under rotating and digging conditions are obtained through the analysis of the sensitivity of the motion parameters,the grouser structure,the layered soil features and the soil heterogeneity.The results indicate that the above parameters remarkably influence the interaction between the DSMV and the seabed soil.Therefore,it is important to consider the rotating and digging motion of the DSMV in practical engineering to develop a detailed optimization design of the track plate.展开更多
目的:了解北京社区人群内源性促红细胞生成素(erythropoietin,EPO)的相关因素及其与10年心血管疾病发病风险的关系。方法:数据来源于2011年12月至2012年4月北京大学第一医院动脉粥样硬化队列的基线资料,采用多因素线性回归模型分析内源...目的:了解北京社区人群内源性促红细胞生成素(erythropoietin,EPO)的相关因素及其与10年心血管疾病发病风险的关系。方法:数据来源于2011年12月至2012年4月北京大学第一医院动脉粥样硬化队列的基线资料,采用多因素线性回归模型分析内源性EPO的相关因素,应用中国动脉粥样硬化性心血管疾病风险预测(prediction for atherosclerotic cardiovascular disease risk in China,China-PAR)模型计算研究对象10年心血管疾病发病风险,以5%、10%为切点定义低、中、高风险分层。结果:共纳入4013名基线无心脑血管疾病、无贫血、肾功能未见异常的研究对象,女性占比62.2%(2496人),平均年龄(55.9±8.2)岁,平均EPO水平为12.8(9.3~17.4)IU/L。10年心血管疾病风险高危者占比25.1%(998人)。多因素回归结果显示,血红蛋白(β=-0.05,95%CI:-0.07~-0.04)和肾小球滤过率≥90 mL/(min·1.73 m^(2))(β=-0.05,95%CI:-0.07~-0.04)与EPO水平呈显著负相关,高血压(β=0.08,95%CI:0.05~0.12)和肥胖(β=0.14,95%CI:0.09~0.18)与内源性EPO水平升高显著相关。10年心血管疾病风险与内源性EPO水平呈显著正相关(β=0.07,95%CI:0.05~0.09),中危者以及高危者内源性EPO水平均显著高于与低危者(P均<0.05)。结论:北京市社区居民内源性EPO水平与血红蛋白、肾功能、肥胖及高血压呈显著相关性,10年心血管疾病风险中、高危者内源性EPO水平显著高于低危者,可能是心血管疾病风险标志物。展开更多
基金supported by the Natural Science Foundation of Hainan Province(Grant No.520LH015)the Fundamental Research Funds for the Central Universities and the Major Projects of Strategic Emerging Industries in Shanghai(Grant No.BH3230001).
文摘To ensure the safe performance of deep-sea mining vehicles(DSMVs),it is necessary to study the mechanical characteristics of the interaction between the seabed soil and the track plate.The rotation and digging motions of the track plate are important links in the contact between the driving mechanism of the DSMV and seabed soil.In this study,a numerical simulation is conducted using the coupled Eulerian–Lagrangian(CEL)large deformation numerical method to investigate the interaction between the track plate of the DSMV and the seabed soil under two working conditions:rotating condition and digging condition.First,a soil numerical model is established based on the elastoplastic mechanical characterization using the basic physical and mechanical properties of the seabed soil obtained by in situ sampling.Subsequently,the soil disturbance mechanism and the dynamic mechanical response of the track plate under rotating and digging conditions are obtained through the analysis of the sensitivity of the motion parameters,the grouser structure,the layered soil features and the soil heterogeneity.The results indicate that the above parameters remarkably influence the interaction between the DSMV and the seabed soil.Therefore,it is important to consider the rotating and digging motion of the DSMV in practical engineering to develop a detailed optimization design of the track plate.
文摘目的:了解北京社区人群内源性促红细胞生成素(erythropoietin,EPO)的相关因素及其与10年心血管疾病发病风险的关系。方法:数据来源于2011年12月至2012年4月北京大学第一医院动脉粥样硬化队列的基线资料,采用多因素线性回归模型分析内源性EPO的相关因素,应用中国动脉粥样硬化性心血管疾病风险预测(prediction for atherosclerotic cardiovascular disease risk in China,China-PAR)模型计算研究对象10年心血管疾病发病风险,以5%、10%为切点定义低、中、高风险分层。结果:共纳入4013名基线无心脑血管疾病、无贫血、肾功能未见异常的研究对象,女性占比62.2%(2496人),平均年龄(55.9±8.2)岁,平均EPO水平为12.8(9.3~17.4)IU/L。10年心血管疾病风险高危者占比25.1%(998人)。多因素回归结果显示,血红蛋白(β=-0.05,95%CI:-0.07~-0.04)和肾小球滤过率≥90 mL/(min·1.73 m^(2))(β=-0.05,95%CI:-0.07~-0.04)与EPO水平呈显著负相关,高血压(β=0.08,95%CI:0.05~0.12)和肥胖(β=0.14,95%CI:0.09~0.18)与内源性EPO水平升高显著相关。10年心血管疾病风险与内源性EPO水平呈显著正相关(β=0.07,95%CI:0.05~0.09),中危者以及高危者内源性EPO水平均显著高于与低危者(P均<0.05)。结论:北京市社区居民内源性EPO水平与血红蛋白、肾功能、肥胖及高血压呈显著相关性,10年心血管疾病风险中、高危者内源性EPO水平显著高于低危者,可能是心血管疾病风险标志物。
