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This work explores an architecture for nonvolatile resistive random-access memory (RRAM) systems. The study proposes a self-rectifying RRAM device utilizing a two-terminal 1R selector that harmonizes the gate control efficacy of transistors with the inherent simplicity of diode structures. A rivet-like HfO2-based RRAM array is meticulously constructed through atomic layer deposition (ALD), aiming to enhance device performance and retention stability. The conformal fabrication technique of ALD method is critical in achieving uniform coverage of isolation layers and precise electrode placement, which is instrumental in the fabrication of high-performance memory cells. Empirical analyses indicate significant improvements in rectification and ON/OFF ratios compared to existing RRAM models, bolstered by compatibility with established CMOS processes. It reveals that these advances are conducive to scalable, high-density memory integration, positioning the RRAM as a viable contender for future computational applications that require high efficiency and neuromorphic computing capabilities. [ABSTRACT FROM AUTHOR]

Heat release rate is a critical parameter in the combustion process, yet its quantification can be challenging to obtain experimentally. In this study, an acoustical measurement system based on the Rijke tube was established to investigate the heat release rate perturbations of 25 propane/air flames under different mixing conditions. For premixed flames, perturbations in CH* and OH* chemiluminescence were consistent with the heat release rate disturbances determined using the acoustical method, thereby validating the proposed acoustical method and platform. Based on these, a comprehensive analysis was carried out on the chemiluminescence results and heat release rate perturbations of flames under different fuel–air mixing conditions, revealing the condition where the chemiluminescence method no longer reliably indicates the heat release rate. The research also investigated the chemiluminescence structure of flames under different fuel–air mixing conditions, identifying a difference in the distribution of CH* and OH* chemiluminescence at higher equivalence ratios (approaching diffusion flame conditions). In fully diffusion flames, the perturbation of OH* chemiluminescence was primarily observed near the base of the flame, while the peak perturbation of CH* chemiluminescence resides within the soot reaction zone downstream of the flame front. [ABSTRACT FROM AUTHOR]

Photo-generated dynamics have been extensively studied in two-dimensional (2D) heterostructures, such as MoSe2/WSe2 and MoSe2/MoS2. Here, we fabricate few-layer PbI2 and monolayer MoSe2 van der Waals (vdW) heterostructures. The excited-wavelength dependent measurements of photoluminescence (PL) and transient dynamic absorption spectra show that there is almost no photo-generated charge transfer between PbI2 and MoSe2. PL changes of MoSe2 are rather dominated by the Fermi level (EF) modulation through the interlayer charge transfer. Density functional theory calculation shows that binding energies in the heterostructures of MoSe2/WSe2 or MoSe2/MoS2 are 2–3 times higher than that of the MoSe2/PbI2 heterostructure, suggesting the weaker interlayer coupling between MoSe2 and PbI2. We propose that the weak interlayer vdW coupling cannot drive the photo-generated interlayer charge transfer while the EF modulation can be achieved through the interlayer charge transfer. The findings will be helpful to fundamental research and applications for novel optoelectronic devices based on 2D material vdW heterostructures. [ABSTRACT FROM AUTHOR]

The integration of the strapdown inertial navigation system (SINS) and Doppler velocity log (DVL) has become a basic navigation solution for Autonomous Underwater Vehicles (AUVs). However, DVL cannot obtain the velocity relative to the ground when the distance between the AUV and seabed is over the operating range, which occurs often when AUVs are sailing in the middle layer of the ocean. When the DVL velocity relative to the current is used for an integrated filter, the unknown current velocity is coupled with the measured velocity error, which decreases the positioning accuracy. To address this problem, the effect of unknown coupled current velocity is analyzed from the perspective of filter observability, and an integrated SINS/DVL/virtual velocity navigation method is proposed. The virtual velocity based on the velocity variation extracted from the inertial measurement unit and DVL is constructed and used as an aided measurement for the Kalman filter. With the help of virtual velocity, the current velocity can be easily decoupled from measured SINS velocity error. The results of simulation and experiments demonstrated that the proposed method can effectively improve both the convergence speed and accuracy of velocity error compared with the classical method with SINS/DVL integration and, thus, significantly improve the positioning accuracy. [ABSTRACT FROM AUTHOR]

Molybdenum oxides have attracted much interest due to their unique electronic properties. Here, we report a convenient and efficient method to synthesize centimeter-scale single crystal of MoO3 ribbons through an atmospheric pressure physical vapor deposition approach. Optical microscopy, atomic force microscopy, high-resolution transmission electron microscopy (HRTEM), selected area electron diffraction, and x-ray diffraction measurements reveal that the MoO3 ribbons grow along the MoO3⟨100⟩ direction and the top surface is MoO3(010) plane. Raman spectroscopy, x-ray photoelectron spectroscopy, and cross-sectional HRTEM results disclose that the surface of MoO3 ribbons can be transformed from MoO3 to MoO2 through H2 annealing treatment forming MoO2/MoO3 heterostructure. We found that the conductance and ultraviolet photoresponsivity of the MoO3 ribbons can be improved by ∼11 and ∼5 orders of magnitude, respectively, after H2 annealing treatment, which will be helpful for the applications of MoO3 in the optoelectronic field. [ABSTRACT FROM AUTHOR]

Estimating inertial measurement unit error without any external reference information has always been a difficult problem. The method based on the reconstruction of the gravitational apparent motion in the inertial frame can estimate the accelerometer bias, but a long identification time is needed to get high alignment accuracy. In order to reduce the convergence time and improve the accuracy of estimation, a fast estimation method based on repetitive navigation under the excitation of swing motion is proposed. Two data processing methods, the forward–forward loop and the backward–forward loop, are studied and compared in this paper. In addition, the influence of data length on the experiment result was analyzed. The simulation and experimental results show that the forward–forward loop calculation cannot solve the contradiction between speed and accuracy, while the backward–forward loop calculation can effectively estimate the accelerometer bias and realize self-alignment, with a short alignment time and high alignment accuracy. [ABSTRACT FROM AUTHOR]

Pose-based action recognition has always been an important research field in computer vision. However, most existing pose-based methods are built upon human skeleton data, which cannot be used to exploit the feature of the motion-related object, i.e., a crucial clue of discriminating human actions. To address this issue, we propose a novel pose-flow relational model, which can benefit from both pose dynamics and optical flow. First, we introduce a pose estimation module to extract the skeleton data of the key person from the raw video. Second, a hierarchical pose-based network is proposed to effectively explore the rich spatial–temporal features of human skeleton positions. Third, we embed an inflated 3D network to capture the subtle cues of the motion-related object from optical flow. Additionally, we evaluate our model on four popular action recognition benchmarks (HMDB-51, JHMDB, sub-JHMDB, and SYSU 3D). Experimental results demonstrate that the proposed model outperforms the existing pose-based methods in human action recognition. [ABSTRACT FROM AUTHOR]