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Gradient heterostructure is one of fundamental interfaces and provides an effective platform to achieve gradually changed properties in mechanics, optics, and electronics. Among different types of heterostructures, the gradient one may provide multiple resistive states and immobilized conductive filaments, offering great prospect for fabricating memristors with both high neuromorphic computation capability and repeatability. Here, we invent a memristor based on a homologous gradient heterostructure (HGHS), comprising a conductive transition metal dichalcogenide and an insulating homologous metal oxide. Memristor made of Ta–TaSxOy–TaS2 HGHS exhibits continuous potentiation/depression behavior and repeatable forward/backward scanning in the read‐voltage range, which are dominated by multiple resistive states and immobilized conductive filaments in HGHS, respectively. Moreover, the continuous potentiation/depression behavior makes the memristor serve as a synapse, featuring broad‐frequency response (10−1–105 Hz, covering 106 frequency range) and multiple‐mode learning (enhanced, depressed, and random‐level modes) based on its natural and motivated forgetting behaviors. Such HGHS‐based memristor also shows good uniformity for 5 × 7 device arrays. Our work paves a way to achieve high‐performance integrated memristors for future artificial neuromorphic computation. We invent a memristor based on a homologous gradient heterostructure (HGHS), comprising a conductive transition metal dichalcogenide and an insulating homologous metal oxide. Memristor made of Ta–TaSxOy–TaS2 HGHS exhibits continuous potentiation/depression behavior and repeatable forward/backward scanning in the read‐voltage range, which are dominated by multiple resistive states and immobilized conductive filaments in HGHS, respectively.

The genus Gracixalus is a group of small and medium-sized rhacophorid frogs for which many new species have been described recently, yet little is known about their biology. Gracixalus weii is a species recently described in Guizhou Province, China, whose acoustic characterization was lacking. The advertisement call has a central role in the reproduction of frogs. We present the first detailed acoustic description for G. weii based on recordings from six individuals obtained at the type locality, Leigongshan Nature Reserve. We collected and analyzed 182 calls, and classified them into two different types (Type A and Type B) based on their call structure and note composition. Type A calls (33 calls from two males) consist of an introductory note followed by two click notes, with a mean total duration of 726.59 ± 119.11 ms and a dominant frequency of 2.46 ± 0.10 kHz. Type B calls (149 calls from all six males) comprise an introductory note and a single click note, mean 481.07 ± 77.03 ms in call duration, with a mean dominant frequency of 2.58 ± 0.15 kHz. Both call types exhibit broad frequency ranges (2.0–21.0 kHz). Among individuals possessing both type A and type B calls, type A calls account for 41.9%–69.0% of the vocalizations, while type B calls comprise 31.0%–58.1%. We found that the type A advertisement call of G. weii is similar to the song structure of the thrush Turdus dissimilis . The complex spectral structure may suggest a case of evolutionary convergence between certain anurans and birds in the use of acoustic signals. The advertisement calls of G. weii are notably distinct from those of other known Gracixalus species. These differences provide acoustic evidence supporting the species taxonomic validity. Our findings underscore the value of bioacoustic data in species identification and contribute basic information for future study on the behavior, ecology, and diversity of the understudied Gracixalus genus.

We present the analysis and start-to-end simulation of an intense narrow-band terahertz (THz) source with a broad tuning range of radiation frequency, using a single-pass free electron laser (FEL) driven by a THz-pulse-train photoinjector. The fundamental radiation frequency, corresponding to the spacing between the electron microbunches, can be easily tuned by varying the spacing time between the laser micropulses. Since the prebunched electron beam is highly bunched at the first several harmonics, with the harmonic generation technique, the radiation frequency range can be further enlarged by several times. The start-to-end simulation results show that this FEL is capable of generating a few tens megawatts power, several tens micro-joules pulse energy, and a few percent bandwidth at the frequencies of 0.5–5 THz. In addition, several practical issues are considered.

The widespread vibration is one of the most promising energy sources for IoT and small sensors, and broad-frequency vibration energy harvesting is important. Triboelectric nanogenerators (TENGs) can convert vibration energy into electrical energy through triboelectricity and electrostatic induction, providing an effective solution to the collection of broad-frequency vibration energy. Also, the power supply in constrained and compact spaces has been a long-standing challenge. Here, a miniaturized power supply (MPS) based on a broad-frequency vibration-driven triboelectric nanogenerator (TENG) is developed. The size of the MPS is 38 mm × 26 mm × 20 mm, which can adapt to most space-limited environments. The TENG device is optimized through theoretical mechanical modeling for the external stimuli, it can efficiently harvest vibrational energy in the frequency range of 1–100 Hz and has a high output power density of 134.11 W/cm3. The developed device demonstrates its practical application potential in powering small electronics like LEDs, watches, and timers.