Structural damage detection using convolutional neural networks combining strain energy and dynamic response

Meccanica - Based on the classification ability of a convolutional neural network (CNN), this paper proposes a structural damage detection method in which a CNN is used to classify the location and...     

Optical and magnetic properties of small-size core–shell Fe3O4@C nanoparticles

Core–shell Fe₃O₄@C magnetic nanoparticles which are of great interest for research have a widely applied prospect. However, people know little about the optical and magnetic properties of the small-size Fe₃O₄@C nanoparticles due to the difficulty of uniformly coating small size Fe₃O₄ nanoparticles. In this paper, the influence of carbon shell coating on the optical and magnetic properties of small size Fe₃O₄ nanoparticles was presented. Carbon coating can strengthen the absorption intensity in the UV–visible light region through the introduction of oxygen defects on the surface of the nanoparticles by nitric acid treatment. Fe₃O₄ and Fe₃O₄@C nanoparticles both display typical superparamagnetic behavior in the high-temperature regime and a blocked state at low temperature from hysteresis loop, zero-field cooled and field cooled curves. Carbon coating reduce the surface uniaxial anisotropy, thus the average blocking temperature <T_B> decreases from 59 K of Fe₃O₄ nanoparticles to 50 K of Fe₃O₄@C nanoparticles.     

合肥光源束流闭轨局部调整和校正

 针对特定实验站调整光源点位置的要求,设计了合肥光源储存环束流闭轨局部调整和校正系统,介绍了该系统的工作原理、硬件组成、软件设计及运行结果,设计要求束流闭轨局部调整的最大幅度为1~2 mm,水平方向和垂直方向其余闭轨畸变均方根分别小于50和30 μm。校正系统采用轨道设定法作为束流闭轨局部调整和校正算法,由束流轨道测量系统、校正铁系统和控制系统组成。运行结果显示：水平和垂直方向分别调节2.0和1.5 mm,水平方向和垂直方向其余闭轨畸变均方根分别为45.14和27.62 μm。     

利用约束线性最小二乘法实现合肥光源束流闭轨全环校正和反馈

由于存在各种非理想因素,束流在储存环中的闭轨会发生畸变。对束流闭轨畸变进行校正的方法较多,目前合肥光源(HLS)采用奇异值分解(SVD)法进行束流闭轨的全环校正和反馈。针对SVD法不足之处,采用约束线性最小二乘法(CLLS)来改进HLS束流闭轨的全环校正和反馈。介绍了束流闭轨畸变校正的理论,着重介绍应用CLLS对HLS储存环束流闭轨畸变进行全环校正和反馈,并给出运行结果。结果显示,利用CLLS后,HLS敏感实验线站的束流轨道稳定性和重复性得到明显改善。