Drop-on-demand (DOD) bioprinting has been widely used in tissue engineering due to its highthroughput efficiency and cost effectiveness. However, this type of bioprinting involves challenges such as satellite generati...Drop-on-demand (DOD) bioprinting has been widely used in tissue engineering due to its highthroughput efficiency and cost effectiveness. However, this type of bioprinting involves challenges such as satellite generation, too-large droplet generation, and too-low droplet speed. These challenges reduce the stability and precision of DOD printing, disorder cell arrays, and hence generate further structural errors. In this paper, a multi-objective optimization (MOO) design method for DOD printing parameters through fully connected neural networks (FCNNs) is proposed in order to solve these challenges. The MOO problem comprises two objective functions: to develop the satellite formation model with FCNNs;and to decrease droplet diameter and increase droplet speed. A hybrid multi-subgradient descent bundle method with an adaptive learning rate algorithm (HMSGDBA), which combines the multisubgradient descent bundle (MSGDB) method with Adam algorithm, is introduced in order to search for the Pareto-optimal set for the MOO problem. The superiority of HMSGDBA is demonstrated through comparative studies with the MSGDB method. The experimental results show that a single droplet can be printed stably and the droplet speed can be increased from 0.88 to 2.08 m·s^-1 after optimization with the proposed method. The proposed method can improve both printing precision and stability, and is useful in realizing precise cell arrays and complex biological functions. Furthermore, it can be used to obtain guidelines for the setup of cell-printing experimental platforms.展开更多
Flexible pipelines are often used to connect hard pipes from a foundation to a superstructure to accommodate large deformation in the base isolation layer during an earthquake. Although Chinese seismic design guidelin...Flexible pipelines are often used to connect hard pipes from a foundation to a superstructure to accommodate large deformation in the base isolation layer during an earthquake. Although Chinese seismic design guidelines suggest several confi gurations, they are diff erent from the designs that have been proven in practice, e.g., Japanese styles, and extensive experimental investigation into their seismic performance is required. Three types of seals, rubber-, metal- and asbestinebased, were tested quasi-statically with infi lled pressurized water at 2.5 MPa. The asbestine-based seal leaked at a smaller deformation than the other two types of seals. Based on the test results, three damage states were defi ned and the deformation capacity was estimated. To evaluate their performance, a three-dimensional model of a base-isolated medical building was developed using OpenSees, with the fl exible pipelines simulated by a mechanical model calibrated from the experimental data. A probabilistic seismic demand model and the fragility function of the fl exible pipelines were then developed to evaluate the seismic performance.展开更多
信息时代网络赋能指挥控制(network enabled command and control,NEC2)的理念,是通过使联网作战兵力信息共享效益最大化,达到作战效能的最大化.通过分析NEC2信息布局应具有的属性要求,提出一种可实现的层次模式联合兵力指挥控制(comman...信息时代网络赋能指挥控制(network enabled command and control,NEC2)的理念,是通过使联网作战兵力信息共享效益最大化,达到作战效能的最大化.通过分析NEC2信息布局应具有的属性要求,提出一种可实现的层次模式联合兵力指挥控制(command and control,C2)连通结构,对其自适应C2特性进行分析,最后结合层次模式指挥控制连通结构信息交换示例,对信息标准交换和按需交换进行介绍,并论述了该连通结构的特性、优点和技术要求.展开更多
文摘Drop-on-demand (DOD) bioprinting has been widely used in tissue engineering due to its highthroughput efficiency and cost effectiveness. However, this type of bioprinting involves challenges such as satellite generation, too-large droplet generation, and too-low droplet speed. These challenges reduce the stability and precision of DOD printing, disorder cell arrays, and hence generate further structural errors. In this paper, a multi-objective optimization (MOO) design method for DOD printing parameters through fully connected neural networks (FCNNs) is proposed in order to solve these challenges. The MOO problem comprises two objective functions: to develop the satellite formation model with FCNNs;and to decrease droplet diameter and increase droplet speed. A hybrid multi-subgradient descent bundle method with an adaptive learning rate algorithm (HMSGDBA), which combines the multisubgradient descent bundle (MSGDB) method with Adam algorithm, is introduced in order to search for the Pareto-optimal set for the MOO problem. The superiority of HMSGDBA is demonstrated through comparative studies with the MSGDB method. The experimental results show that a single droplet can be printed stably and the droplet speed can be increased from 0.88 to 2.08 m·s^-1 after optimization with the proposed method. The proposed method can improve both printing precision and stability, and is useful in realizing precise cell arrays and complex biological functions. Furthermore, it can be used to obtain guidelines for the setup of cell-printing experimental platforms.
基金Scientific Research Fund of Institute of Engineering Mechanics,CEA under Grant Nos.2016A05 and 2016A06the International Science and Technology Cooperation Program of China under Grant No.2014DFA70950the National Natural Science Foundation of China under Grant No.51378478
文摘Flexible pipelines are often used to connect hard pipes from a foundation to a superstructure to accommodate large deformation in the base isolation layer during an earthquake. Although Chinese seismic design guidelines suggest several confi gurations, they are diff erent from the designs that have been proven in practice, e.g., Japanese styles, and extensive experimental investigation into their seismic performance is required. Three types of seals, rubber-, metal- and asbestinebased, were tested quasi-statically with infi lled pressurized water at 2.5 MPa. The asbestine-based seal leaked at a smaller deformation than the other two types of seals. Based on the test results, three damage states were defi ned and the deformation capacity was estimated. To evaluate their performance, a three-dimensional model of a base-isolated medical building was developed using OpenSees, with the fl exible pipelines simulated by a mechanical model calibrated from the experimental data. A probabilistic seismic demand model and the fragility function of the fl exible pipelines were then developed to evaluate the seismic performance.
文摘信息时代网络赋能指挥控制(network enabled command and control,NEC2)的理念,是通过使联网作战兵力信息共享效益最大化,达到作战效能的最大化.通过分析NEC2信息布局应具有的属性要求,提出一种可实现的层次模式联合兵力指挥控制(command and control,C2)连通结构,对其自适应C2特性进行分析,最后结合层次模式指挥控制连通结构信息交换示例,对信息标准交换和按需交换进行介绍,并论述了该连通结构的特性、优点和技术要求.
