@article{qi_huang_fu_li_zhou_jiang_2019, title={Modeling of the flexoelectric annular microplate based on strain gradient elasticity theory}, volume={26}, ISSN={["1537-6532"]}, DOI={10.1080/15376494.2018.1455935}, abstractNote={ABSTRACT A size-dependent annular microplate model is established based on the isotropic flexoelectric theory, which considering the effects of strain gradient, polarization gradient, and microscopic electrical field gradient. The displacement mode of the Kirchhoff plate theory is used to obtain the detailed expressions of the electric enthalpy, dynamic energy, and the work done by external forces. The governing equations, boundary conditions, and initial conditions are derived using the Hamilton's principle. By solving the governing equations with only mechanical and only electrical boundary conditions, the analytical solutions of deflection and polarization in the static direct and converse flexoelectric responses are obtained, respectively. Meanwhile, the free vibration problem is also solved. Finally, based on the analytical solutions, some numerical results are given to illustrate the unique flexoelectric properties of the annular microplate compared with the solid circular microplate and influence of the strain gradient elastic effect on the static direct and converse flexoelectric responses as well as the natural frequency.}, number={23}, journal={MECHANICS OF ADVANCED MATERIALS AND STRUCTURES}, author={Qi, Lu and Huang, Shujin and Fu, Guangyang and Li, Anqing and Zhou, Shenjie and Jiang, Xiaoning}, year={2019}, month={Dec}, pages={1958–1968} }
 @article{zhang_lv_zhang_huang_wong_yau_chen_wen_jiang_zeng_et al._2019, title={Modulating the Electrical Transport in the Two-Dimensional Electron Gas at LaAlO3/SrTiO3 Heterostructures by Interfacial Flexoelectricity}, volume={122}, ISSN={["1079-7114"]}, DOI={10.1103/PhysRevLett.122.257601}, abstractNote={Thin film flexoelectricity is attracting more attention because of its enhanced effect and potential application in electronic devices. Here we find that a mechanical bending induced flexoelectricity significantly modulates the electrical transport properties of the interfacial two-dimensional electron gas (2DEG) at the LaAlO_{3}/SrTiO_{3} (LAO/STO) heterostructure. Under variant bending states, both the carrier density and mobility of the 2DEG are changed according to the flexoelectric polarization direction, showing an electric field effect modulation. By measuring the flexoelectric response of LAO, it is found that the effective flexoelectricity in the LAO thin film is enhanced by 3 orders compared to its bulk. These results broaden the horizon of study on the flexoelectricity effect in the hetero-oxide interface and more research on the oxide interfacial flexoelectricity may be stimulated.}, number={25}, journal={PHYSICAL REVIEW LETTERS}, author={Zhang, Fan and Lv, Peng and Zhang, Yiteng and Huang, Shujin and Wong, Chi-Man and Yau, Hei-Man and Chen, Xinxin and Wen, Zheng and Jiang, Xiaoning and Zeng, Changgan and et al.}, year={2019}, month={Jun} }
 @article{kim_chang_kim_huang_jiang_2019, title={Stress Measurement of a Pressurized Vessel Using Candle Soot Nanocomposite Based Photoacoustic Excitation}, volume={10971}, ISSN={["1996-756X"]}, DOI={10.1117/12.2515211}, abstractNote={This article aims to develop a pressure sensing method by utilizing both a contacting active sensor and a non-contacting laser ultrasound transmitter. An overloaded stress in an industrial pressure tank such as a nuclear reactor may cause a catastrophic explosion; thus, it is essential to monitor the mechanical stress in a reliable manner for the structural safety. Among many different types of stress sensing methods, ultrasound sensing has been attractive due to its non-invasive measurement feature. For the recent decades, subsurface longitudinal (SSL) ultrasonic wave has been widely used since it is not only less dependent on the internal medium and the surface condition, but also has the fastest wave speed without wave distortion. In our work, laser source and Aluminum nitride (AlN) wafer are used to generate and to receive SSL ultrasonic waves, respectively. In order to increase the photoacoustic efficacy, a composite of carbon-soot nanoparticles (CSNP) and polydimethylsiloxane (PDMS) was attached onto the intermediate wedge at the transmitter side. The photoacoustic experiment results demonstrate a reasonable linear relationship between the stress level and the time-of-flight variation of the propagated wave signal.}, journal={NONDESTRUCTIVE CHARACTERIZATION AND MONITORING OF ADVANCED MATERIALS, AEROSPACE, CIVIL INFRASTRUCTURE, AND TRANSPORTATION XIII}, author={Kim, Ho-Wuk and Chang, Wei-Yi and Kim, Taeyang and Huang, Shujin and Jiang, Xiaoning}, year={2019} }
 @article{huang_yau_yu_qi_so_dai_jiang_2018, title={Flexoelectricity in a metal/ferroelectric/semiconductor heterostructure}, volume={8}, ISSN={["2158-3226"]}, DOI={10.1063/1.5031162}, abstractNote={The flexoelectricity in a 100 nm-thick BaTiO3 (BTO) thin film based metal/ferroelectric insulator/semiconductor (MFS) heterostructure was reported in this letter. The transverse flexoelectric coefficient of the BTO thin film in the heterojunction structure was measured to be 287-418 μC/m at room temperature, and its temperature dependence shows that the flexoelectric effect in the BTO thin film was dominated in the paraelectric phase. We showed that the BTO thin film capacitance could be controlled at multi-levels by introducing ferroelectric and flexoelectric polarization in the film. These results are promising for understanding of the flexoelectricity in epitaxial ferroelectric thin films and practical applications of the enhanced flexoelectricity in nanoscale devices.}, number={6}, journal={AIP ADVANCES}, author={Huang, Shujin and Yau, Hei-Man and Yu, Hyeonggeun and Qi, Lu and So, Franky and Dai, Ji-Yan and Jiang, Xiaoning}, year={2018}, month={Jun} }
 @misc{huang_qi_huang_shu_zhou_jiang_2018, title={Flexoelectricity in dielectrics: Materials, structures and characterizations}, volume={8}, ISSN={["2010-1368"]}, DOI={10.1142/s2010135x18300025}, abstractNote={ Flexoelectricity in dielectrics suggests promising smart structures for sensors, actuators and transducers. In this review, dielectric materials, structures and the associated flexoelectric characterization methods are presented. First of all, we review structures and methods to measure different flexoelectric coefficients, including [Formula: see text], etc., via direct or converse flexoelectric effect. The flexoelectric materials in the form of bulk, thin films and 2D materials and the reported flexoelectric properties of these dielectrics will then be discussed. Semiconductor materials and the associated flexoelectric studies will also be reviewed. The progress of flexoelectric device study will next be presented, followed by the flexoelectricity research challenges and future trend. }, number={2}, journal={JOURNAL OF ADVANCED DIELECTRICS}, author={Huang, Shujin and Qi, Lu and Huang, Wenbin and Shu, Longlong and Zhou, Shenjie and Jiang, Xiaoning}, year={2018}, month={Apr} }
 @article{qi_huang_fu_zhou_jiang_2018, title={On the mechanics of curved flexoelectric microbeams}, volume={124}, ISSN={["1879-2197"]}, DOI={10.1016/j.ijengsci.2017.11.022}, abstractNote={Based on the flexoelectric theory incorporating strain gradient and polarization gradient, a flexoelectric curved microbeam model is established. The governing equations, boundary conditions and initial conditions are derived by Hamilton's principle. Both the static bending and natural vibration problems are solved. The direct and converse flexoelectric responses are numerically analyzed. In the direct flexoelectric response, more collected charges are expected in the beam with larger original curvature for simply supported boundary, but the opposite is true for clamped boundary. In the converse flexoelectric response, the voltage-induced bending exists even in a clamped curved beam while it is not the case for a clamped straight beam and larger original curvature always implies larger deflection for both boundary conditions. In addition, the strain gradient elastic effect is found to reduce both the flexoelectric responses especially when the thickness is comparable to the length scale parameter associated with strain gradient.}, journal={INTERNATIONAL JOURNAL OF ENGINEERING SCIENCE}, author={Qi, Lu and Huang, Shujin and Fu, Guangyang and Zhou, Shenjie and Jiang, Xiaoning}, year={2018}, month={Mar}, pages={1–15} }
 @article{huang_kim_hou_cann_jones_jiang_2017, title={Flexoelectric characterization of BaTiO3-0.08Bi(Zn1/2Ti1/2)O-3}, volume={110}, number={22}, journal={Applied Physics Letters}, author={Huang, S. J. and Kim, T. and Hou, D. and Cann, D. and Jones, J. L. and Jiang, X. N.}, year={2017} }
 @article{huang_chang_kim_li_huang_jiang_2016, title={A Novel Laser Ultrasound Transducer Using Candle Soot Carbon Nanoparticles}, volume={15}, ISSN={["1941-0085"]}, DOI={10.1109/tnano.2016.2536739}, abstractNote={As a novel composite material for laser ultrasound transducer, candle soot nanoparticles polydimethylsiloxane (CSPs-PDMS) has been demonstrated to generate high frequency, broadband, and high-amplitude ultrasound waves. In this study, we investigated the mechanism of the high-optoacoustic conversion efficiency exhibited by the composite. A thermal-acoustic coupling model was proposed for analyzing the performance of the composite. The theoretical result matches well with the experimental observation. The acoustic beam profile was compared with Field II simulation results. The 4.41 × 10-3 energy conversion coefficient and 21 MHz--6 dB frequency bandwidth of the composite suggest that CSPs-PDMS composites is promising for a broad range of ultrasound therapy and non-destructive testing applications.}, number={3}, journal={IEEE TRANSACTIONS ON NANOTECHNOLOGY}, author={Huang, Wenbin and Chang, Wei-Yi and Kim, Jinwook and Li, Sibo and Huang, Shujin and Jiang, Xiaoning}, year={2016}, month={May}, pages={395–401} }
 @inproceedings{kim_chang_huang_jiang_2016, title={Nanocomposite transducer with a laser ultarsound transmitter and a piezoelectric receiver}, DOI={10.1109/nano.2016.7751440}, abstractNote={Laser ultrasound transducers, converting the laser pulses into acoustic waves with high frequency, broadband and high pressure amplitude, is attractive to many biomedical and industrial applications. In this paper, nanocomposites consisting of carbon nanomaterials, PDMS and PVDF were incorporated into a transducer structure for ultrasound transmitting and receiving. The prototyped nanocomposite transducers were characterized by conducting pulse-echo tests. The obtained center frequency is 12 MHz, -6 dB fractional bandwidth is 138%, and the signal-to-noise ratio of 42 dB with an excitation of ~5 mJ of 532 nm, 6 ns pulsed laser. These initial findings strongly suggest that laser ultrasound transducers are promising for advanced ultrasound imaging applications.}, booktitle={2016 IEEE 16th International Conference on Nanotechnology (IEEE-nano)}, author={Kim, J. and Chang, W. Y. and Huang, S. J. and Jiang, X. N.}, year={2016}, pages={191–192} }
 @article{kim_huang_huang_jiang_2016, title={Thermal gradient induced flexoelectric effects in bulk Ba0.67Sr0.33TiO3}, volume={108}, ISSN={["1077-3118"]}, DOI={10.1063/1.4949358}, abstractNote={Flexoelectric effect, denoting electric field gradient induced mechanical strain or mechanical strain gradient induced electric polarization, is a universal phenomenon in all dielectrics. Although research on the topic of flexoelectricity under stress fields and electric fields has advanced significantly, information regarding the phenomenon under thermal fields is rather limited. In this letter, the flexoelectricity field of Ba0.67Sr0.33TiO3 (BST) was investigated by generating temperature gradients along the lengths of samples with symmetric geometry. An electric field gradient induced by a thermal gradient was analyzed based on the temperature-dependent dielectric property of BST. The strain was then experimentally verified due to the electric field gradient. Experimental results suggest converse flexoelectric effect of BST samples with symmetric geometry in a thermal field. This result was not only consistent with the theoretical prediction, but it also followed the scaling effect of flexoelectricity.}, number={19}, journal={APPLIED PHYSICS LETTERS}, author={Kim, Taeyang and Huang, Wenbin and Huang, Shujin and Jiang, Xiaoning}, year={2016}, month={May} }