通讯机构:
[Yuehua Li] S;School of Electrical Engineering, University of South China, Hengyang 421001, China
关键词:
Pixel circuit;Threshold voltage variation;Mobility variation;Voltage drop;Thin-film transistor
摘要:
A pixel circuit with p-type low temperature poly-silicon thin-film transistors (TFTs) is presented for active -matrix organic light-emitting diode displays. This circuit consists of five TFTs and one capacitor. In the circuit, the characteristics, i.e., the threshold voltage and the mobility, are extracted by the mirroring structure, and an adaptive voltage is generated at the gate of the TFT in the programming stage. Therefore, only one capacitor is needed to compensate both the threshold voltage variation and the mobility variation. Meanwhile, in the circuit, the voltage drop of the power line is also compensated. Moreover, the circuit can prevent the image flicker because the organic lighting-emitting diode (OLED) only operates in the emission stage. The circuit simulation results indicate that the OLED current error rates are lower than 4.61% when the threshold voltage variation is +/- 0.5 V, lower than 6.92% when the mobility variation is +/- 30%, and lower than 3.96% when the voltage drop is -0.5 V.
期刊:
IEEE Transactions on Intelligent Vehicles,2023年:1-15 ISSN:2379-8858
作者机构:
[Jiang C.; Wang Z.; Liang H.] Hefei Institutes of Physical Science, Chinese Academy of Sciences, Hefei, China;[Wang Y.] School of Electrical Engineering, University of South China, Hengyang, China
摘要:
This paper presents a novel online adaptive method for estimating the process and measurement noise covariance matrices in Kalman filters (KFs) to address the challenge of varying noise characteristics in practical applications. Specifically, the proposed method decomposes the noise covariance matrix into an element distribution matrix and a noise intensity and employs an improved Sage filter to estimate the element distribution matrix. Additionally, a calibration and correction method is introduced to accurately determine and adaptively correct the online bias of the noise intensity. The unbiasedness and convergence of the proposed method are mathematically proven under the condition that the system is detectable. Moreover, this method is applied to multiobject tracking (MOT) based on KFs and light detection and ranging (LiDAR), and it is evaluated on the KITTI dataset and the official KITTI server. The experimental results demonstrate that the proposed method achieves significantly improved MOT performance based on KFs and outperforms other LiDAR-based methods on the KITTI leaderboard. This method provides a new approach for enhancing the performance of KFs and assisting with MOT, and it has practical feasibility for real-world applications. IEEE
摘要:
Anisotropic plasmonic metasurfaces have attracted broad research interest since they possess novel optical properties superior to natural materials and their tremendous design flexibility. However, the realization of multi-wavelength selective plasmonic metasurfaces that have emerged as promising candidates to uncover multichannel optical devices remains a challenge associated with weak modulation depths and narrow operation bandwidth. Herein, we propose and numerically demonstrate near-infrared multi-wavelength selective passive plasmonic switching (PPS) that encompasses high ON/OFF ratios and strong modulation depths via multiple Fano resonances (FRs) in anisotropic plasmonic metasurfaces. Specifically, the double FRs can be fulfilled and dedicated to establishing tailorable near-infrared dual-wavelength PPS. The multiple FRs mediated by in-plane mirror asymmetries cause the emergence of triple-wavelength PPS, whereas the multiple FRs governed by in-plane rotational asymmetries avail the implementation of the quasi-bound states in the continuum-endowed multi-wavelength PPS with the ability to unfold a tunable broad bandwidth. In addition, the strong polarization effects with in-plane anisotropic properties further validate the existence of the polarization-resolved multi-wavelength PPS. Our results provide an alternative approach to foster the achievement of multifunctional meta-devices in optical communication and information processing.
期刊:
Progress in Organic Coatings,2023年183:107819 ISSN:0300-9440
通讯作者:
Li, ZY;Wang, XZ;Ying, L
作者机构:
[Li, ZY; Li, Zhenye; Kang, Xiaomin; Wang, Gaoyang; Zhang, Meng] Univ South China, Coll Mech Engn, Hengyang 421001, Peoples R China.;[Wang, Xingzhu; Wang, XZ] Univ South China, Sch Elect Engn, Hengyang 421001, Peoples R China.;[Ying, Lei; Ying, L] South China Univ Technol, Inst Polymer Optoelect Mat & Devices, State Key Lab Luminescent Mat & Devices, Guangzhou 510640, Peoples R China.
通讯机构:
[Li, ZY ; Wang, XZ ] U;[Ying, L ] S;Univ South China, Coll Mech Engn, Hengyang 421001, Peoples R China.;Univ South China, Sch Elect Engn, Hengyang 421001, Peoples R China.;South China Univ Technol, Inst Polymer Optoelect Mat & Devices, State Key Lab Luminescent Mat & Devices, Guangzhou 510640, Peoples R China.
关键词:
Titanium dioxide;Hole transport layer;Polymer solar cells;Power conversion efficiency;Stability
摘要:
Poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS) has been widely served as the state-of-art hole transport layer (HTL) for high performance organic solar cells (OSCs) due to its easy solution processability, excellent hole extraction ability, and well compatibility with various active layers. However, PEDOT:PSS shows several drawbacks such as relatively moderate conductivity and optical transparency, acidity, and reactivity, which directly limits the improvement of device performance and leads to the deterioration of device stability. In this work, metal oxide titanium dioxide (TiO2) was doped into the conventional HTL-material PEDOT:PSS, which simultaneously boosted the power conversion efficiency (PCE) and stability of OSCs based on PBDB-T:N2200. The simultaneous improvement in PCE and stability is originated from the effectively improved light trans-mittance and conductivity of PEDOT:PSS, increased hole extraction of the active layer, as well as the optimized ohmic contact between the interface layer and the electrode. In addition, the TiO2 doping PEDOT:PSS strategy is proved to be general to a variety of OSCs systems, which is expected to bring new opportunities for the devel-opment of high performance HTL, so as to promote the commercialization of OSCs.
摘要:
Abstract: In practical wireless sensor networks (WSNs), cascading failures are closely related to network load distribution, which in turn strongly relies on the locations of multiple sink nodes. For such a network, understanding how the multisink placement affects its cascading robustness is essential but still largely missing in the field of complex networks. To this end, this paper puts forward an actual cascading model for WSNs based on the multisink-oriented load distribution characteristics, in which two load redistribution mechanisms (i.e., global routing and local routing) are designed to imitate the most commonly used routing schemes. On this basis, a number of topological parameters are considered to quantify the sinks’ locations, and then, the relationship between these quantities with network robustness is investigated on two typical WSN topologies. Moreover, by employing the simulated annealing approach, we find the optimal multisink placement for maximizing network robustness and compare the topological quantities before and after the optimization to validate our findings. The results indicate that for the sake of enhancing the cascading robustness of a WSN, it is better to place its sinks as hubs and decentralize these sinks, which is independent of network structure and routing scheme. Keywords: wireless sensor networks; cascading failures; multisink placement; routing scheme; robustness
作者机构:
[Liu, Luxuan; Tang, Dongbao; Jia, Zhaoyuan; Tan, Yuyu] Univ South China, Sch Elect Engn, Ultrafast Micronano Technol & Adv Laser Mfg Key La, Hengyang 421001, Peoples R China.;[Duan, Ziwei] Sun Yat Sen Univ, Sch Biomed Engn, Shenzhen Campus, Shenzhen 518107, Peoples R China.;[Lang, Lijun] Chinese Univ Hong Kong, Dept Comp Sci & Engn, Ho Sin Hang Engn Bldg, Hong Kong 999077, Peoples R China.
摘要:
Traditional centrifuges, extensively employed in biology, chemistry, medicine, and other domains for tasks such as blood separation and pathogen extraction, have certain limitations. Their high cost, substantial size, and reliance on electricity restrict their range of application. Contemporary centrifuges, inspired by everyday items like paper trays and egg beaters, boast characteristics such as ease of operation, independence from electricity, and portability. These features offer unique advantages in specific situations, such as electricity shortages, inadequate infrastructure, and challenging medical conditions. Consequently, we designed a hand-powered portable centrifuge driven by pulling a rope. Our experiments revealed significant performance factors, including load capacity, rope length, and frequency of rope pulling. The results demonstrated that the revolutions per minute (RPM) of a hand-powered portable centrifuge were directly proportional to the length of the rope and the frequency of pulling, up to a certain limit, while inversely proportional to the load. When used for separating and washing polystyrene microspheres, the portable centrifuge's performance equaled that of traditional centrifuges. According to relevant calculations, this centrifuge could be capable of meeting the application of blood separation. Therefore, we believe this portable centrifuge will find meaningful applications in similar areas, particularly in resource-poor settings.
摘要:
A new method of numerical simulating prediction and decontamination effect evaluation for abrasive jet decontamination to radioactively contaminated metal is proposed. Based on the Computational Fluid Dynamics and Discrete Element Model (CFD-DEM) coupled simulation model, the motion patterns and distribution of abrasives can be predicted, and the decontamination effect can be evaluated by image processing and recognition technology. The impact of three key parameters (impact distance, inlet pressure, abrasive mass flow rate) on the decontamination effect is revealed. Moreover, here are experiments of reliability verification to decontamination effect and numerical simulation methods that has been conducted. The results show that: 60Co and other homogeneous solid solution radioactive pollutants can be removed by abrasive jet, and the average removal rate of Co exceeds 80%. It is reliable for the proposed numerical simulation and evaluation method because of the well goodness of fit between predicted value and actual values: The predicted values and actual values of the abrasive distribution diameter are 057 and 055; the total coverage rate is 26.42% and 23.50%; the average impact velocity is 81.73 m/s and 78.00 m/s. Further analysis shows that the impact distance has a significant impact on the distribution of abrasive particles on the target surface, the coverage rate of the core area increases at first, and then decreases with the increase of the impact distance of the nozzle, which reach a maximum of 14.44% at 300 mm. It is recommended to set the impact distance around 300 mm, because at this time the core area coverage of the abrasive is the largest and the impact velocity is stable at the highest speed of 81.94 m/s. The impact of the nozzle inlet pressure on the decontamination effect mainly affects the impact kinetic energy of the abrasive and has little impact on the distribution. The greater the inlet pressure, the greater the impact kinetic energy, and the stronger the decontamination ability of the abrasive. But in return, the energy consumption is higher, too. For the decontamination of radioactively contaminated metals, it is recommended to set the inlet pressure of the nozzle at around 0.6 MPa. Because most of the Co elements can be removed under this pressure. Increasing the mass and flow of abrasives appropriately can enhance the decontamination effectiveness. The total mass of abrasives per unit decontamination area is suggested to be 50 g because the core area coverage rate of the abrasive is relatively large under this condition; and the nozzle wear extent is acceptable. (c) 2023 Korean Nuclear Society, Published by Elsevier Korea LLC. This is an open access article under the
摘要:
Industrial robots need to accurately identify the position and rotation angle of the handwheel of chemical raw material barrel valves during the process of opening and closing, in order to avoid interference between the robot gripper and the handwheel. This paper proposes a handwheel keypoint detection algorithm for fast and accurate acquisition of handwheel position and rotation pose. The algorithm is based on the Keypoint R-CNN (Region-based Convolutional Neural Network) keypoint detection model, which integrates the lightweight mobile network MobileNetV3, the Coordinate Attention module, and improved BiFPN (Bi-directional Feature Pyramid Network) structure to improve the detection speed of the model, enhance the feature extraction performance of the handwheel, and improve the expression capability of small targets at keypoint locations. Experimental results on a self-built handwheel dataset demonstrate that the proposed algorithm outperforms the Keypoint R-CNN model in terms of detection speed and accuracy, with a speed improvement of 54.6%. The detection accuracy and keypoint detection accuracy reach 93.3% and 98.7%, respectively, meeting the requirements of the application scenario and enabling accurate control of the robot's rotation of the valve handwheel.
作者机构:
[Chen, Zenghui; Luo, Yonggang] Univ South China, Sch Elect Engn, Hunan Prov Key Lab Ultrafast Micro Nano Technol &, Hengyang 421001, Peoples R China.;[Deng, Li] Univ South China, Sch Mech Engn, Hengyang 421001, Peoples R China.;[Chen, Zenghui] Univ South China, Sch Elect Engn, Hengyang 421001, Peoples R China.
通讯机构:
[Chen, ZH ] U;Univ South China, Sch Elect Engn, Hengyang 421001, Peoples R China.
关键词:
Optical frequency comb;I;Q demodulation;Optical vector network analysis
摘要:
An ultrafast optical vector network analysis (OVNA) based on dual optical frequency comb (OFC) and I/Q demodulation technology is proposed and demonstrated. The responses of the DUT with broadband are characterized by propagating the signal OFC through the DUT, and then detecting interference signals using digital signal processor with retrieval algorithm. Without the need of the acousto-optic modulator or optical filter in the scheme, the frequency aliasing can be eliminated by using the I/Q demodulation module, so that the spectral utilization efficiency of the OFC is improved significantly. Meanwhile, the wideband measurement with high acquisition rates can also be achieved. In simulation process, the single spectrum of HCN molecule with linewidth of 1 GHz and bandwidth of 10 GHz can be rapidly measured, and the measurement time is only 1 mu s in theory. Our proposed OVNA opens the door to realize a real-time detection in the field of trace molecular sensing.
摘要:
PrBa(Co1-xFex)2O5+d polymorphs (0.1 < x < 0.4, denoted as PBCF-x with Fe-doping level x) are reported and dual phase of cubic phase Pr0.5Ba0.5Co1_xFexO3_d and tetragonal phase PrBa(Co1-xFex)2O5+d are co-produced through an common sol-gel method. The co-generation of the dual-phases leads to the formation of abundant hetero-interfaces be-tween the neighboring crystal phases and the synergic effect demonstrates remarkably high oxygen adsorption and dissociation ability in the air. The density functional theory (DFT) calculation establishes that the existence of hetero-interfaces promotes oxygen reduction reaction activity (ORR) which is crucial to improve cathode performance of proton-conducing solid oxide fuel cells (H-SOFCs). Moreover, an outstanding electro-chemical performance is obtained for the single cell with a PBCF03 cathode and the research demonstrates that a self-assemble dual phase cathode can be an effective approach for developing high-performing H-SOFCs.(c) 2023 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.
摘要:
Cathode current is a key measure of the rated power of the diode and is closely related to the cathode structure. Compared with 5 cathode and helical cathode, the mesh cathode has been more widely used in high-power tetrode, because of its structural advantage. So far, the relationship between the space charge limited current (SCLC) and the cathode structure for thermionic emission mesh cathode diode has not been reported. In this article, we develop a calculation expression of the SCLC for the mesh cathode coaxial cylindrical diode, which is based on the calculation model of the helical cathode. The results show that the calculated values are in excellent agreement with the simulated values based on CST Particle Studio. In addition, we study the dependence of the SCLC of the mesh cathode diode with the change of the cathode height, radius of the cathode filament, anode voltage, and density of the mesh. It is helpful for the optimization of the cathode structure design of vacuum tubes and microwave tubes with the coaxial cylinder mesh cathode structure.
通讯机构:
[Li, Y.; Yue, W.] S;[Yin, J.] H;Hunan Province Key Laboratory for Ultra-Fast Micro/Nano Technology and Advanced Laser Manufacture, China;School of Information Science and Engineering, China
关键词:
Health monitoring;Multifunctional flexible sensor;Nanofiber;Pressure sensing;Temperature sensing
摘要:
Flexible multifunctional sensor with excellent performance via unsophisticated fabrication method is impera-tively anticipated for the development of smart human health monitoring systems and wearable electronic de-vices. Here, we report a multilayer dual-mode flexible sensor (DMFS) by integrating different sensing layers on the two sides of a flexible dielectric substrate for sensing pressure and temperature. The introduction of elastic nanofiber skeleton structure and internal "sea urchin" like conductive materials is the top priority for the DMFS to have excellent sensing performance and durability. As a result, the fabricated DMFS ultimately shows excellent pressure sensitivity of 111.96 kPa-1 within a wide sensing range up to 70 kPa. In the case of temperature stimulus, the DMFS accomplishes a high, linear response to the ambient temperature variation within the range from 20 degrees C to 50 degrees C, while maintaining high stability and durability after long-term bending cycles. In addition, DMFS reveals its great potential for non-contact dynamic temperature measurement by being integrated into an intelligent temperature monitoring system. Most importantly, a novel smart human health-monitoring system, which attributes to the coordination and common work of multiple DMFS, has been developed and realizes simultaneous detection of multiple physiological signals of human beings in real-time.
作者机构:
[Luo, Xiao-Qing; Zhu, Weihua; Xu, Xiaofeng; Liu, Qin-Ke; Luo, XQ; Chen, Zhiyong; Wang, Xin-Lin] Univ South China, Sch Elect Engn, Nano Technol & Adv Laser Mfg, Hunan Prov Key Lab Ultra Fast Micro, Hengyang 421001, Peoples R China.;[Li, Yan] Univ South China, Sch Nucl Sci & Technol, Hengyang 421001, Peoples R China.;[Liu, W. M.] Chinese Acad Sci, Inst Phys, Beijing Natl Lab Condensed Matter Phys, Beijing 100190, Peoples R China.;[Wang, Xin-Lin] Univ South China, Sch Mech Engn, Hengyang 421001, Peoples R China.
通讯机构:
[Luo, XQ ] U;Univ South China, Sch Elect Engn, Nano Technol & Adv Laser Mfg, Hunan Prov Key Lab Ultra Fast Micro, Hengyang 421001, Peoples R China.
摘要:
The bound states in the continuum (BICs) in optical metasurfaces have latterly received prominent attention for their ultrahigh quality factors and the promise that they hold for realizing lowthreshold nanolasers, high-harmonic generation, and slow-light devices. In this scenario, the flexible tuning of the BIC is at the heart of multifunctional and tunable metadevices underpinning the central role in the modulation of optical spectral responses. Most BIC-inspired works are limited to single types of BICs modes only affected by the structural perturbation without tunable functionality, while different types of BIC modes have received little attention in manipulating the spectral line shapes in optical metasurface. Here, we show that the simultaneous generation and tailored interplay of two types of BIC modes can empower the realization of tailorable spectral lineshape manipulation in all-dielectric metasurfaces. In particular, the magnetic symmetry-protected BICs and accidental BIC result from the preserved reflection symmetry and geometrical parameter perturbation, respectively. The varied asymmetric parameters and the polarization angle of the incident light are responsible for the generation and interplay of the symmetry-protected and accidental quasi-BIC modes. Additionally, the interplaying quasi-BICs enable the implementation of the dual-wavelength passive optical switches throughout the related telecom bands, and can exhibit the tunable spectral features of different types of Fano resonances and EIT analog-based slow-light effect. These results could offer exploration potential for the development of multifunction and high-performance metadevices.
通讯机构:
[Xingzhu Wang] S;[Baomin Xu] D;School of Electrical Engineering, University of South China, Hengyang, 421001 China<&wdkj&>Department of Materials Science and Engineering and Shenzhen Engineering Research and Development Center for Flexible Solar Cells, Southern University of Science and Technology, Shenzhen, 518055 China<&wdkj&>Key University Laboratory of Highly Efficient Utilization of Solar Energy and Sustainable Development of Guangdong, Southern University of Science and Technology, Shenzhen, 518055 China<&wdkj&>Shenzhen Putai Technology Co., Ltd, Shenzhen, 518110 China<&wdkj&>Department of Materials Science and Engineering and Shenzhen Engineering Research and Development Center for Flexible Solar Cells, Southern University of Science and Technology, Shenzhen, 518055 China<&wdkj&>Key University Laboratory of Highly Efficient Utilization of Solar Energy and Sustainable Development of Guangdong, Southern University of Science and Technology, Shenzhen, 518055 China<&wdkj&>Guangdong-Hong Kong-Macao Joint Laboratory for Photonic-Thermal-Electrical Energy Materials and Devices, Southern University of Science and Technology, Shenzhen, 518055 China
关键词:
defect passivations;double-side optimizations;flexible perovskite solar cells;high performances
摘要:
Although much progress is made toward enhancing the efficiency of perovskite solar cells (PSCs), their operational reliability, particularly their mechanical stability, which is a crucial factor for flexible PSCs (f-PCSs), has not attracted sufficient attention. The defects in the perovskite layer, especially on the top and the buried surface of the perovskite layer, can induce perovskite fracture, highly limiting the performance of f-PSCs. Herein, a novel multifunctional organic salt, metformin hydrochloride, which can passivate cationic and anionic defects, is incorporated on both the top and buried surfaces of perovskite layer to suppress defects. As a result, a power conversion efficiency (PCE) of 24.40% for rigid PSCs and a PCE of 22.04% for f-PSCs are achieved. Simultaneously, the device can retain 90% and 80% of the initial efficiency after 1000 h of light illumination and 10 000 bending cycles, respectively, showing excellent operational stability. This study may provide a global way to design a passivation strategy and fabricate flexible perovskite solar cells with high efficiency and stability.