The initial stresses widely exist in elastic materials.While achieving a continuum stress-free configuration through compatible unloading is desirable,mechanical unloading alone frequently proves insufficient,posing c...The initial stresses widely exist in elastic materials.While achieving a continuum stress-free configuration through compatible unloading is desirable,mechanical unloading alone frequently proves insufficient,posing challenges in avoiding virtual stress-free configurations.In this paper,we introduce a novel concept of equivalent temperature variation to counteract the incompatible initial strain.Our focus is on initially stressed cylindrical and spherical elastomers,where we first derive the Saint-Venant,Beltrami-Michell,and Volterra integral conditions in orthogonal curvilinear coordinates using the exterior differential form theory.It is shown that for any given axially or spherically distributed initial stress,an equivalent temperature variation always exists.Furthermore,we propose two innovative initial stress forms based on the steady-state heat conduction.By introducing an equivalent temperature variation,the initial stress can be released through a compatible thermo-mechanical unloading process,offering valuable insights into the constitutive theory of initially stressed elastic materials.展开更多
目的:构建一套科学客观的能力评价体系,用于评估临床研究协调员(clinical research coordinator,CRC)在临床研究中的能力水平。方法:通过本中心既往的项目管理工作经验及文献回顾,确定CRC临床研究能力的评估指标,结合临床试验开展流程...目的:构建一套科学客观的能力评价体系,用于评估临床研究协调员(clinical research coordinator,CRC)在临床研究中的能力水平。方法:通过本中心既往的项目管理工作经验及文献回顾,确定CRC临床研究能力的评估指标,结合临床试验开展流程和项目质控结果,搭建CRC的评价体系,并将该评价体系应用于CRC在临床研究中实际工作能力的评估,验证评价体系的客观性、科学性以及可行性。结果:该评价体系结果与既往人工评估结果一致,年资和学历影响临床研究能力。结论:该评价体系能够科学客观地反映CRC的临床研究能力,为CRC的职业发展和管理层的决策提供理论基础。展开更多
输电网灵活性受到节点灵活性与网络传输灵活性耦合影响且灵活性供需平衡关系随源荷波动动态变化,所以有必要开展输电网多元灵活性资源协调规划研究。该文针对输电网潮流动态变化的特点,构建一种反应灵活性资源传输需求和网络传输能力动...输电网灵活性受到节点灵活性与网络传输灵活性耦合影响且灵活性供需平衡关系随源荷波动动态变化,所以有必要开展输电网多元灵活性资源协调规划研究。该文针对输电网潮流动态变化的特点,构建一种反应灵活性资源传输需求和网络传输能力动态匹配程度的网络传输灵活性指标;然后,建立包含储能装置与统一潮流控制器(unified power flow controller,UPFC)的输电网多元灵活性资源两阶段协调优化规划模型;最后,通过算例分析验证所提的网络传输灵活性指标能够定量地反应网络传输灵活性随源荷波动的动态变化,基于网络传输灵活性最优的两阶段规划模型,有利于更好地挖掘原网络的传输能力,规划方案对更高的源-荷波动水平具有更好的适应性,提出的灵活性重要度指标可为灵活性资源初步选址提供指导。展开更多
基金Project supported by the National Natural Science Foundation of China(Nos.12241205 and 12032019)the National Key Research and Development Program of China(No.2022YFA1203200)the Strategic Priority Research Program of Chinese Academy of Sciences(Nos.XDB0620101 and XDB0620103)。
文摘The initial stresses widely exist in elastic materials.While achieving a continuum stress-free configuration through compatible unloading is desirable,mechanical unloading alone frequently proves insufficient,posing challenges in avoiding virtual stress-free configurations.In this paper,we introduce a novel concept of equivalent temperature variation to counteract the incompatible initial strain.Our focus is on initially stressed cylindrical and spherical elastomers,where we first derive the Saint-Venant,Beltrami-Michell,and Volterra integral conditions in orthogonal curvilinear coordinates using the exterior differential form theory.It is shown that for any given axially or spherically distributed initial stress,an equivalent temperature variation always exists.Furthermore,we propose two innovative initial stress forms based on the steady-state heat conduction.By introducing an equivalent temperature variation,the initial stress can be released through a compatible thermo-mechanical unloading process,offering valuable insights into the constitutive theory of initially stressed elastic materials.
文摘目的:构建一套科学客观的能力评价体系,用于评估临床研究协调员(clinical research coordinator,CRC)在临床研究中的能力水平。方法:通过本中心既往的项目管理工作经验及文献回顾,确定CRC临床研究能力的评估指标,结合临床试验开展流程和项目质控结果,搭建CRC的评价体系,并将该评价体系应用于CRC在临床研究中实际工作能力的评估,验证评价体系的客观性、科学性以及可行性。结果:该评价体系结果与既往人工评估结果一致,年资和学历影响临床研究能力。结论:该评价体系能够科学客观地反映CRC的临床研究能力,为CRC的职业发展和管理层的决策提供理论基础。
文摘输电网灵活性受到节点灵活性与网络传输灵活性耦合影响且灵活性供需平衡关系随源荷波动动态变化,所以有必要开展输电网多元灵活性资源协调规划研究。该文针对输电网潮流动态变化的特点,构建一种反应灵活性资源传输需求和网络传输能力动态匹配程度的网络传输灵活性指标;然后,建立包含储能装置与统一潮流控制器(unified power flow controller,UPFC)的输电网多元灵活性资源两阶段协调优化规划模型;最后,通过算例分析验证所提的网络传输灵活性指标能够定量地反应网络传输灵活性随源荷波动的动态变化,基于网络传输灵活性最优的两阶段规划模型,有利于更好地挖掘原网络的传输能力,规划方案对更高的源-荷波动水平具有更好的适应性,提出的灵活性重要度指标可为灵活性资源初步选址提供指导。
