Ningyi Zhang Chen, C., Cai, F., Zhu, Y., Liao, L., Qian, J., Yuan, F.-G., & Zhang, N. (2019). 3D printing of electroactive PVDF thin films with high beta-phase content. SMART MATERIALS AND STRUCTURES, 28(6). https://doi.org/10.1088/1361-665X/ab15b7 Huang, W., Yang, S., Zhang, N., Yuan, F.-G., & Jiang, X. (2015). Direct Measurement of Opening Mode Stress Intensity Factors Using Flexoelectric Strain Gradient Sensors. EXPERIMENTAL MECHANICS, 55(2), 313–320. https://doi.org/10.1007/s11340-014-9914-y Huang, W., Yang, S., Zhang, N., Yuan, F.-G., & Jiang, X. (2014). Cracks Monitoring and Characterization Using Ba0.64Sr0.36TiO3 Flexoelectric Strain Gradient Sensors. SENSORS AND SMART STRUCTURES TECHNOLOGIES FOR CIVIL, MECHANICAL, AND AEROSPACE SYSTEMS 2014, Vol. 9061. https://doi.org/10.1117/12.2045166