The time-history responses of the surface were obtained for a linear elastic half-plane including regularly distributed enormous embedded circular cavities subjected to propagating obliquely incident plane SH-waves. A...The time-history responses of the surface were obtained for a linear elastic half-plane including regularly distributed enormous embedded circular cavities subjected to propagating obliquely incident plane SH-waves. An advanced numerical approach named half-plane time-domain boundary element method（BEM）, which only located the meshes around the cavities, was used to create the model. By establishing the modified boundary integral equation（BIE）independently for each cavity and forming the matrices, the final coupled equation was solved step-by-step in the timedomain to obtain the boundary values. The responses were developed for a half-plane with 512 cavities. The amplification patterns were also obtained to illustrate the frequencydomain responses for some cases. According to the results,the presence of enormous cavities affects the scattering and diffraction of the waves arrived to the surface. The introduced method can be recommended for geotechnical/mechanical engineers to model structures in the fields of earthquake engineering and composite materials.展开更多
With the continuous development of information technology,data centers(DCs)consume significant and evergrowing amounts of electrical energy.Renewable energy sources(RESs)can act as clean solutions to meet this require...With the continuous development of information technology,data centers(DCs)consume significant and evergrowing amounts of electrical energy.Renewable energy sources(RESs)can act as clean solutions to meet this requirement without polluting the environment.Each DC serves numerous users for their data service demands,which are regarded as flexible loads.In this paper,the willingness to pay and time sensitivities of DC users are firstly explored,and the user-side demand response is then devised to improve the overall benefits of DC operation.Then,a Stackelberg game between a DC and its users is proposed.The upper-level model aims to maximize the profit of the DC,in which the time-varying pricing of data services is optimized,and the lower-level model addresses user’s optimal decisions for using data services while balancing their time and cost requirements.The original bi-level optimization problem is then transformed into a single-level problem using the Karush-Kuhn-Tucker optimality conditions and strong duality theory,which enables the problem to be solved efficiently.Finally,case studies are conducted to demonstrate the feasibility and effectiveness of the proposed method,as well as the effects of the time-varying data service price mechanism on the RES accommodation.展开更多
Nutrition during perinatal period is more critical for the developme nt of the immune system than during adulthood, and the relationship between earl y nutrition and diseases in later life has been established. In hum...Nutrition during perinatal period is more critical for the developme nt of the immune system than during adulthood, and the relationship between earl y nutrition and diseases in later life has been established. In humans and labor atory animals, the plasticity of metabolic function in foetuses or neonates enab les them to adapt to malnutrition for survival; however, such an adaptation, as usually evidenced by retarded growth, stunted development of lymphoid organs and impaired immunocompetence, can maintain and persist into later life even when n utrition is improved. Early nutrition may thus programme' the immune system of a nimals. Limited experimental studies have also revealed that long-term immunity against nematode parasites in sheep can be enhanced by a short-term protein su pplementation shortly after weaning, a form of 'nutritional programming', but su ch an effect appears to vanish if the nutritional status of young animals alread y meets at least the requirement for maintenance.展开更多
文摘The time-history responses of the surface were obtained for a linear elastic half-plane including regularly distributed enormous embedded circular cavities subjected to propagating obliquely incident plane SH-waves. An advanced numerical approach named half-plane time-domain boundary element method（BEM）, which only located the meshes around the cavities, was used to create the model. By establishing the modified boundary integral equation（BIE）independently for each cavity and forming the matrices, the final coupled equation was solved step-by-step in the timedomain to obtain the boundary values. The responses were developed for a half-plane with 512 cavities. The amplification patterns were also obtained to illustrate the frequencydomain responses for some cases. According to the results,the presence of enormous cavities affects the scattering and diffraction of the waves arrived to the surface. The introduced method can be recommended for geotechnical/mechanical engineers to model structures in the fields of earthquake engineering and composite materials.
基金supported in part by National Natural Science Foundation of China(No.U1910216)in part by Science and Technology Project of State Grid Zhejiang Electric Power Co.,Ltd.(No.5211JY19000T)。
文摘With the continuous development of information technology,data centers(DCs)consume significant and evergrowing amounts of electrical energy.Renewable energy sources(RESs)can act as clean solutions to meet this requirement without polluting the environment.Each DC serves numerous users for their data service demands,which are regarded as flexible loads.In this paper,the willingness to pay and time sensitivities of DC users are firstly explored,and the user-side demand response is then devised to improve the overall benefits of DC operation.Then,a Stackelberg game between a DC and its users is proposed.The upper-level model aims to maximize the profit of the DC,in which the time-varying pricing of data services is optimized,and the lower-level model addresses user’s optimal decisions for using data services while balancing their time and cost requirements.The original bi-level optimization problem is then transformed into a single-level problem using the Karush-Kuhn-Tucker optimality conditions and strong duality theory,which enables the problem to be solved efficiently.Finally,case studies are conducted to demonstrate the feasibility and effectiveness of the proposed method,as well as the effects of the time-varying data service price mechanism on the RES accommodation.
文摘利用温控负荷(thermostatically controlled load,TCL)作为调频资源参与电网调频是应对高比例可再生能源发电并网导致电力系统维持频率稳定能力下降的有效手段。文中提出一种基于动态下垂控制的TCL一次调频控制策略,考虑聚合商TCL平均温度状态(state of temperature,SOT)、调频容量和系统频率变化率,构建动态下垂控制模型,实时调整下垂控制系数,改变TCL聚合商调频参与度。当向上调频时,锁定关状态TCL;当向下调频时,锁定开状态TCL,确保频率快速恢复至额定值附近。同时,为确保用户的舒适度,利用TCL的SOT优先级排序列表派遣法,确定TCL参与调频顺序。在Matlab/Simulink平台上进行仿真分析,仿真结果验证了文中所提策略在确保用户舒适度、改善频率质量等方面的有效性。
文摘Nutrition during perinatal period is more critical for the developme nt of the immune system than during adulthood, and the relationship between earl y nutrition and diseases in later life has been established. In humans and labor atory animals, the plasticity of metabolic function in foetuses or neonates enab les them to adapt to malnutrition for survival; however, such an adaptation, as usually evidenced by retarded growth, stunted development of lymphoid organs and impaired immunocompetence, can maintain and persist into later life even when n utrition is improved. Early nutrition may thus programme' the immune system of a nimals. Limited experimental studies have also revealed that long-term immunity against nematode parasites in sheep can be enhanced by a short-term protein su pplementation shortly after weaning, a form of 'nutritional programming', but su ch an effect appears to vanish if the nutritional status of young animals alread y meets at least the requirement for maintenance.
