Lei Shao’s research while affiliated with Shanghai Jiao Tong University and other places

... Wu et al. [96] achieved an order-of-magnitude tunability in comb spacing by examining the changes in the excitation frequency influence on the energy transfer between coupled modes. Different forms of energy transfer contribute to the evolution of the frequency comb, resulting in the coexistence of periodic orbits, quasi-periodic orbits, and chaotic attractors [97] . Studies on frequency combs based on the internal resonance in high-Q quartz resonators [98] and thinfilm resonators [99] have demonstrated that strong nonlinearity and tightly coupled modes are essential for frequency comb generation. ...

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Recent advancements of nonlinear dynamics in mode coupled microresonators: a review

... Their phononic and miniature analog, also known as (micro)mechanical frequency combs (MFCs), have also attracted great attention recently but are nontrivial due to the distinctively different dispersion of phonons. Building upon Cao et al.'s theoretical prediction of MFCs in coupled nonlinear mechanical resonator chains (Fermi-Pasta-Ulam α chain) [8], the physics of MFCs has been mainly studied via phononic mode coupling involving parametric excitation [9][10][11][12][13], internal resonance [14][15][16][17][18][19][20], and self-excitation by negative dissipation [21,22]. As their typical lower frequency range from kHz to GHz, MFCs could provide chipscale timekeeping with the potential of surpassing existing quartz or micromechanical resonators [23][24][25][26]. ...

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Self-Injection Locked and Phase Offset-Free Micromechanical Frequency Combs

... Figure 3 shows the phenomena, mechanisms, and control methods for the thermal runaway problem. Generally, several external phenomena and interface characteristic can indicate the potential risks of thermal runaway such as a surface temperature rise and voltage rapid drop [56], smoke dissipation and pungent odor [57], shell swelling [58], localized discoloration [59], etc. ...

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An Overview About Second-Life Battery Utilization for Energy Storage: Key Challenges and Solutions

... The overview of vibration monitoring methods is given in [1]. The vision-based vibration monitoring techniques use image correlation [2][3][4], optical flow [5][6][7] and edge detection [8][9][10]. In [8] the edge displacement is measured through matching and tracking of virtual homologous points. ...

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Vibration monitoring using sub-pixel edge localization

... FabricWorm integrates textiles with 3D-printed parts and springs, while MiniFabricWorm achieves movement with no rigid parts. Guo et al. [53] developed soft textile robots with an internal PET bladder, combining textiles with nonlinear inflation for complex shape morphing inspired by mollusks and plants. They demonstrated continuous rolling, bidirectional crawling, and in-pipe crawling using a single pressure source by encoding sewing constraints onto highly elastic anisotropic fabric. ...

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Inflatable Kirigami Crawlers

... In practical applications, typically, modes other than basic Rayleigh modes are used, namely, Sezawa, pseudo-bulk, or bulk modes. In terms of applied designs, interdigital transducers [3,4] and layered resonators [5] are used to generate acoustic waves. Another dimension of complexity and opportunities stems from the fact that nitride layers are deposited on different types of heterostructure substrates, which creates opportunities for the additional modification of transducer characteristics by modifying the topology of the entire heterostructure, such as by adding additional grooves to increase their sensitivity [6] or by using a multilayer structure that supports more propagation modes compared to bulk materials. ...

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Study of Acoustic Emission from the Gate of Gallium Nitride High Electron Mobility Transistors

... OriWheelBot in four scenarios with varying n values(2, 4, 8, and 16), demonstrating its adaptability to different configurations. Further work is to develop the third generation of the OriWheelBot, which will be equipped with high-performance sensors, power supplies, smart material actuators, etc., and consider radiation and other extreme environments[51][52][53][54][55].For example, Figs. 10b and 10c demonstrate the conceptual diagram of OriWheelBot applications in planetary exploration and disaster area rescue, respectively. Future studies could design and lightweight the OriWheelBot even more, perhaps by substituting lattice materials for the primary load-bearing component ...

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An origami-wheeled robot with variable width and enhanced sand walking versatility

... Spherical piezoelectric transducers are the optimal choice to realize omnidirectional radiation, which is widely used in marine exploitation, structural health detection, and energy collection [1][2][3]. Spherical piezoelectric transducers are usually composite metals to enhance structural strength and improve impedance matching. Wang et al. proposed a sandwiched spherical piezoelectric transducer to enhance the heat dissipation capacity of the spherical transducer through composite metal [4,5]; Tang et al. proposed a cascade spherical piezoelectric transducer to increase the electrical power of the spherical piezoelectric transducer [6,7]; and Kong et al. presented a novel spherical piezoceramic transducer called a spherical smart aggregate, which can be embedded in concrete structures for health monitoring [8,9]. ...

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Study on Vibration Characteristics of Functionally Graded Material Composite Spherical Piezoelectric Transducer

... The equation was treated numerically and with semi-numerical methods (for example, the wavelet-based computational algorithms method [4], the iteration method with the use of the Elzaki transform [5], the modified variational iteration method with Adomian method [6], the variational iteration method (VIM) associated with formable transformation [7], etc.) and semi-analytic methods [8]. To obtain the vibration property of (4), various analytic solving procedures are also developed, including harmonic and energy balance methods [9,10], various perturbation methods [11][12][13][14][15][16][17], the non-perturbative methodology [18], etc. Based on the obtained approximate results, it is seen that the frequency of vibration depends on the initial amplitude, and the frequency-amplitude relation for the Duffing oscillator is defined [19][20][21][22][23][24][25]. ...

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Approximate Analytic Frequency of Strong Nonlinear Oscillator

... Most high piezoelectric response and large ferroelectric polarization in experiments occurred in tetragonal phase or mixed phases 13 . Here, we focus on the P4mm (space group) tetragonal phase (other tetragonal perovskite phases are not ferroelectric or piezoelectric) and a longstanding problem, piezoelectric anisotropy, which is fundamentally important for modern engineering applications like ultrasonic transducers 14 and robotic metamaterials 15 . Highly anisotropic materials can provide minimal noise from lateral vibrations, greatly reducing manufacturing costs by skipping the precise control of the size of pezoelectric vibrator, eg., the length/thickness ratio, to produce the clean thickness resonance mode. ...

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Understanding the intrinsic piezoelectric anisotropy of tetragonal ABO3 perovskites through a high-throughput study