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Recently, memristors have garnered widespread attention as neuromorphic devices that can simulate synaptic behavior, holding promise for future commercial applications in neuromorphic computing. In this paper, we present a memristor with an Au/Bi3.2La0.8Ti3O12 (BLTO)/ITO structure, demonstrating a switching ratio of nearly 103 over a duration of 104 s. It successfully simulates a range of synaptic behaviors, including long-term potentiation and depression, paired-pulse facilitation, spike-timing-dependent plasticity, spike-rate-dependent plasticity etc. Interestingly, we also employ it to simulate pain threshold, sensitization, and desensitization behaviors of pain-perceptual nociceptor (PPN). Lastly, by introducing memristor differential pairs (1T1R-1T1R), we train a neural network, effectively simplifying the learning process, reducing training time, and achieving a handwriting digit recognition accuracy of up to 97.19 %. Overall, the proposed device holds immense potential in the field of neuromorphic computing, offering possibilities for the next generation of high-performance neuromorphic computing chips.

Abstract Nanomaterials based pressure sensors have obtained world‐wide research interest due to their promising potential applications in health monitoring, artificial intelligence, and electronic skin (e‐skin). Despite the recent progress in sensitivity and detection range of the pressure sensors, the relatively high thickness of the active films has obstructed their applications for e‐skin and degraded the comfortability as wearable devices. We hereby report for the first time a novel pressure sensor based on two‐dimensional metal oxide nanosheets where the gaps between neighboring nanosheets are adjustable. The pressure sensors show a sensitivity of up to 7.2 × 106 kPa–1, which is the highest value ever reported for a pressure sensor. Additionally, the sensor shows good repeatability and excellent stability. The pressure‐sensing ranges can be tuned by adjusting the coverage of the nanosheet film. This work presents an effective strategy to develop ultrathin pressure sensors.

Objective To investigate the clinical significance of intraoperative B⁃ultrasound real⁃ time monitoring in craniotomy for patients with severe traumatic brain injury (sTBI). Methods From March 2017 to June 2019, 64 patients withs TBI who met the admission criteria were in cluded in the study. Craniotomy and/or decompressiv ecraniectomy were performed. According to the application of real⁃time B⁃ultrasound⁃guided surgery, the patients were randomly divided into 2 groups: ultrasound group (n=32) and control group (n=32). The operation time, the number of new hematoma during and after operation, the probability of bone flap removal, the probability of second operation and Glasgow Coma Scale (GCS) score were recorded. Glasgow Outcome Scale (GOS) was used to evaluate the prognosis and calculate the good prognosisrate. Results In the ultrasound group, 32 cases were successfully operated under the guidance of B⁃ultrasound, and the detection rate of new hematoma was 76% (19/25). The rate of hematoma clearance rate >90% [84.38% (27/32) vs. 59.38% (19/32); χ2=4.947, P=0.026], GCS score at 3 d after operation (11.38±3.54vs.9.19±3.81; t=2.382, P=0.020) and good prognosis rate at discharge [56.25% (18/32) vs. 31.25% (10/32) ; χ2=0.077, P=0.038] in the ultrasound group were higher than those in the control group, but there were no significant differences in the operation time, the probability of bone flap removal and the probability of second operation between 2 groups (P>0.05,forall). Conclusions Intraoperativ ereal⁃time B⁃ultrasound⁃guided surgery can improve the prognosis of patients withs TBI. DOI：10.3969/j.issn.1672⁃6731.2020.08.007

Flexible sensors are the essential foundations of pressure sensing, microcomputer sensing systems, and wearable devices. The flexible tactile sensor can sense stimuli by converting external forces into electrical signals. The electrical signals are transmitted to a computer processing system for analysis, realizing real-time health monitoring and human motion detection. According to the working mechanism, tactile sensors are mainly divided into four types—piezoresistive, capacitive, piezoelectric, and triboelectric tactile sensors. Conventional silicon-based tactile sensors are often inadequate for flexible electronics due to their limited mechanical flexibility. In comparison, polymeric nanocomposites are flexible and stretchable, which makes them excellent candidates for flexible and wearable tactile sensors. Among the promising polymers, conjugated polymers (CPs), due to their unique chemical structures and electronic properties that contribute to their high electrical and mechanical conductivity, show great potential for flexible sensors and wearable devices. In this paper, we first introduce the parameters of pressure sensors. Then, we describe the operating principles of resistive, capacitive, piezoelectric, and triboelectric sensors, and review the pressure sensors based on conjugated polymer nanocomposites that were reported in recent years. After that, we introduce the performance characteristics of flexible sensors, regarding their applications in healthcare, human motion monitoring, electronic skin, wearable devices, and artificial intelligence. In addition, we summarize and compare the performances of conjugated polymer nanocomposite-based pressure sensors that were reported in recent years. Finally, we summarize the challenges and future directions of conjugated polymer nanocomposite-based sensors.

Traditional utilization of photo-induced excitons is popularly but restricted in the fields of photovoltaic devices as well as photodetectors, and efforts on broadening its function have always been attempted. However, rare reports are available on organic field effect transistor (OFET) memory employing photo-induced charges. Here, we demonstrate an OFET memory containing a novel organic lanthanide complex Eu(tta)3ppta (Eu(tta)3 = Europium(III) thenoyltrifluoroacetonate, ppta = 2-phenyl-4,6-bis(pyrazol-1-yl)-1,3,5-triazine), in which the photo-induced charges can be successfully trapped and detrapped. The luminescent complex emits intense red emission upon ultraviolet (UV) light excitation and serves as a trapping element of holes injected from the pentacene semiconductor layer. Memory window can be significantly enlarged by light-assisted programming and erasing procedures, during which the photo-induced excitons in the semiconductor layer are separated by voltage bias. The enhancement of memory window is attributed to the increasing number of photo-induced excitons by the UV light. The charges are stored in this luminescent complex for at least 104 s after withdrawing voltage bias. The present study on photoassisted novel memory may motivate the research on a new type of light tunable charge trapping photo-reactive memory devices. [ABSTRACT FROM AUTHOR]

High-performance organic field-effect transistor nonvolatile memories have been achieved using sputtered C nanoparticles as the nano-floating-gate. The sputtered C nano-floating-gate is prepared with low-cost material and simple process, forming uniform and discrete charge trapping sites covered by a smooth and complete polystyrene layer. The devices show large memory window, excellent retention capability, and programming/reading/erasing/reading endurance. The sputtered C nano-floating-gate can effectively trap both holes and electrons, and it is demonstrated to be suitable for not only p-type but also n-type organic field-effect transistor nonvolatile memories. [ABSTRACT FROM AUTHOR]

The bilayer ambipolar organic field-effect transistors (OFETs) based on 1,8-naphthoylene (trifluoromethylbenzimidazole)-4,5-dicarboxylic acid imide (NTFBII)/pentacene heterojunction have been probed. The origin of the bias stress instability in the top n-channel is attributed to the electron trapping at the NTFBII/pentacene interface, whereas the bias stress effect in the bottom p-channel is associated mainly with the pentacene/dielectric interface. The contact resistances for electron and hole injection are strongly dependent on the local conductivity of the NTFBII and pentacene layers, respectively. The Cu penetration into NTFBII to form direct contact to pentacene is proposed to be the hole injection mechanism in the bilayer ambipolar OFETs. [ABSTRACT FROM AUTHOR]