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- 2017
- spectral reconstruction
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- Optoelectronic Information Science and Engineering
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- Zhejiang University
- Guilin University of Aerospace Technology
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Ultra-High-Speed 2:1 Digital Selector and Plasmonic Modulator IM/DD Transmitter Operating at 222 GBaud for Intra-Datacenter Applications
摘要： This paper presents a physics-based compact modeling approach that incorporates the impact of total ionizing dose (TID) and stress-induced defects into simulations of metal-oxide-semiconductor (MOS) devices and integrated circuits (ICs). This approach utilizes calculations of surface potential (ψs) to capture the charge contribution from oxide trapped charge and interface traps and to describe their impact on MOS electrostatics and device operating characteristics as a function of ionizing radiation exposure and aging effects. The modeling approach is demonstrated for bulk and silicon-on-insulator (SOI) MOS device. The formulation is verified using TCAD simulations and through the comparison of model calculations and experimental I-V characteristics from irradiated devices. The modeling approach is suitable for simulating TID and aging effects in advanced MOS devices and ICs, and is compatible with modern MOSFET compact modeling techniques. A circuit-level demonstration is given for TID and aging effects in SRAM cells.
关键词： compact modeling,SOI,ionizing radiation,semiconductor devices,MOSFET,Aging effects
更新于2025-09-23 15:19:57
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[IEEE 2020 10th Annual Computing and Communication Workshop and Conference (CCWC) - Las Vegas, NV, USA (2020.1.6-2020.1.8)] 2020 10th Annual Computing and Communication Workshop and Conference (CCWC) - DFB Laser Chip Defect Detection Based on Successive Subspace Learning
摘要： This paper presents a physics-based compact modeling approach that incorporates the impact of total ionizing dose (TID) and stress-induced defects into simulations of metal-oxide-semiconductor (MOS) devices and integrated circuits (ICs). This approach utilizes calculations of surface potential (ψs) to capture the charge contribution from oxide trapped charge and interface traps and to describe their impact on MOS electrostatics and device operating characteristics as a function of ionizing radiation exposure and aging effects. The modeling approach is demonstrated for bulk and silicon-on-insulator (SOI) MOS device. The formulation is verified using TCAD simulations and through the comparison of model calculations and experimental I-V characteristics from irradiated devices. The modeling approach is suitable for simulating TID and aging effects in advanced MOS devices and ICs, and is compatible with modern MOSFET compact modeling techniques. A circuit-level demonstration is given for TID and aging effects in SRAM cells.
关键词： MOSFET,SOI,semiconductor devices,compact modeling,ionizing radiation,Aging effects
更新于2025-09-23 15:19:57
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[IEEE 2019 IEEE 5th International Conference on Computer and Communications (ICCC) - Chengdu, China (2019.12.6-2019.12.9)] 2019 IEEE 5th International Conference on Computer and Communications (ICCC) - Nonuniformity Correction Algorithm for TEC-less Uncooled Infrared Imaging System
摘要： An aging and more sedentary population requires interventions aimed at monitoring physical activity, particularly within the home. This research uses simulation, optimization, and regression analyses to assess the feasibility of using a small number of sensors to track movement and infer physical activity levels of older adults. Based on activity data from the American Time Use Survey and assisted living apartment layouts, we determined that using three to four doorway sensors can be used to effectively capture a suf?cient amount of movements in order to estimate activity. The research also identi?ed preferred approaches for assigning sensor locations, evaluated the error magnitude inherent in the approach, and developed a methodology to identify which apartment layouts would be best suited for these technologies.
关键词： geriatrics,smart homes,senior citizens,sensors,successful aging,gerontology,Biomedical monitoring
更新于2025-09-23 15:19:57
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Plasmonic FET Terahertz Spectrometer
摘要： An aging and more sedentary population requires interventions aimed at monitoring physical activity, particularly within the home. This research uses simulation, optimization, and regression analyses to assess the feasibility of using a small number of sensors to track movement and infer physical activity levels of older adults. Based on activity data from the American Time Use Survey and assisted living apartment layouts, we determined that using three to four doorway sensors can be used to effectively capture a suf?cient amount of movements in order to estimate activity. The research also identi?ed preferred approaches for assigning sensor locations, evaluated the error magnitude inherent in the approach, and developed a methodology to identify which apartment layouts would be best suited for these technologies.
关键词： successful aging,gerontology,smart homes,Biomedical monitoring,sensors,senior citizens,geriatrics
更新于2025-09-23 15:19:57
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Accelerated aging of absorber coatings for CSP receivers under real high solar flux – Evolution of their optical properties
摘要： The use of durable high solar absorptance receivers is a key element in a CSP plant project. In this article, different receiver materials are studied: four alloy substrates (T91, T22, VM12, Inconel 617) combined with four new absorber coatings, operable in solar towers with molten salts or steam as heat transfer fluids, and a classic Pyromark? paint considered as a reference. In order to test the durability of the coatings, 200 solar accelerated aging cycles were applied on the samples, using a concentrated solar facility (named SAAF). The cycles were defined so as to apply realistic high solar flux and temperature on the front side of the samples, and with high cooling and heating rates reproducing the fast variation of solar irradiation due to cloudy weather and subsequent thermal shocks. The optical characteristics of the coatings were measured at the beginning and at regular intervals during the aging procedure. Different behaviors of the coatings were observed depending on the substrate, before any aging cycle. After this first aging campaign, some evolutions were observed on the solar absorptance or thermal emittance, depending on the substrate and the coating. Nevertheless, the degradations noticed are not significant enough to conclude about the durability of the coatings.
关键词： Optical characterization,CSP receiver absorber coatings,Solar furnace,Accelerated aging
更新于2025-09-19 17:15:36
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Aging effects on prefrontal cortex oxygenation in a posture-cognition dual-task: an fNIRS pilot study
摘要： Background: The aging process alters upright posture and locomotion control from an automatically processed to a more cortically controlled one. The present study investigated a postural-cognitive dual-task paradigm in young and older adults using functional Near-Infrared Spectroscopy (fNIRS). Methods: Twenty healthy participants (10 older adults 72 ± 3 y, 10 young adults 23 ± 3 y) performed a cognitive (serial subtractions) and a postural task (tandem stance) as single-tasks (ST) and concurrently as a dual-task (DT) while the oxygenation levels of the dorsolateral prefrontal cortex (DLPFC) were measured. Results: In the cognitive task, young adults performed better than older adults in both conditions (ST and DT) and could further increase the number of correct answers from ST to DT (all ps ≤ 0.027) while no change was found for older adults. No significant effects were found for the postural performance. Cerebral oxygenation values (O2Hb) increased significantly from baseline to the postural ST (p = 0.033), and from baseline to the DT (p = 0.031) whereas no changes were found in deoxygenated hemoglobin (HHb). Finally, the perceived exertion differed between all conditions (p ≤ 0.003) except for the postural ST and the DT (p = 0.204). Conclusions: There was a general lack of age-related changes except the better cognitive performance under motor-cognitive conditions in young compared to older adults. However, the current results point out that DLPFC is influenced more strongly by postural than cognitive load. Future studies should assess the different modalities of cognitive as well as postural load.
关键词： Attention,Functional near-infrared spectroscopy (fNIRS),Postural control,Aging,Dual-tasking,Executive control,Balance,Elderly
更新于2025-09-19 17:15:36
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The effect of imprint on remanent piezoelectric properties and ferroelectric aging of PbZr <sub/>0.52</sub> Ti <sub/>0.48</sub> O <sub/>3</sub> thin films
摘要： Ferroelectric films suffer from both aging and degradation under high ac-field drive conditions due to loss of polarization with time. In this study, the roles of defect chemistry and internal electric fields on the long-term stability of the properties of piezoelectric films were explored. For this purpose, lead zirconate titanate (PZT) films with a Zr/Ti ratio of 52/48 doped with Mn- (PMZT) or Nb- (PNZT) were deposited on Pt coated Si substrates by the sol-gel method. It was demonstrated that the magnitude of the internal field is much higher in PMZT films compared to PNZT films after poling in the temperature range of 25-200°C under an electric field of -240 kV/cm. The development of the internal field is thermally activated, with activation energies from 0.5±0.06 to 0.8±0.1 eV in Mn doped films and from 0.8±0.1 to 1.2±0.2 eV in Nb doped films. The different activation energies for imprint suggests that the physical mechanism underlying the evolution of the internal field in PMZT and PNZT films differs; the enhanced internal field upon poling is attributed to (1) alignment of oxygen vacancy – acceptor ion defect dipoles (((Mn''_Ti - V_O^{??})_x, (Mn'_Ti - V_O^{??})') in PMZT films, and (2) thermionic injection of electron charges and charge trapping in PNZT films. In either case, the internal field reduces back switching, enhances the remanent piezoelectric properties, and dramatically improves the aging behavior. PMZT films exhibited the greatest enhancement, with reduced high temperature (180°C) aging rates of 2-3%/decade due to improved stability of the poled state. In contrast, PNZT films showed significantly larger high temperature aging rates (15.5%/decade) in the piezoelectric coefficient, demonstrating that the fully poled state was not retained with time.
关键词： aging,PZT,sol-gel,thin film,donor,acceptor,imprint
更新于2025-09-19 17:15:36
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[IEEE 2019 Conference on Lasers and Electro-Optics Europe & European Quantum Electronics Conference (CLEO/Europe-EQEC) - Munich, Germany (2019.6.23-2019.6.27)] 2019 Conference on Lasers and Electro-Optics Europe & European Quantum Electronics Conference (CLEO/Europe-EQEC) - Towards a Suburban Quantum Network Link
摘要： This paper presents a physics-based compact modeling approach that incorporates the impact of total ionizing dose (TID) and stress-induced defects into simulations of metal-oxide-semiconductor (MOS) devices and integrated circuits (ICs). This approach utilizes calculations of surface potential (ψs) to capture the charge contribution from oxide trapped charge and interface traps and to describe their impact on MOS electrostatics and device operating characteristics as a function of ionizing radiation exposure and aging effects. The modeling approach is demonstrated for bulk and silicon-on-insulator (SOI) MOS device. The formulation is verified using TCAD simulations and through the comparison of model calculations and experimental I-V characteristics from irradiated devices. The modeling approach is suitable for simulating TID and aging effects in advanced MOS devices and ICs, and is compatible with modern MOSFET compact modeling techniques. A circuit-level demonstration is given for TID and aging effects in SRAM cells.
关键词： compact modeling,SOI,ionizing radiation,semiconductor devices,MOSFET,Aging effects
更新于2025-09-19 17:13:59
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[IEEE 2019 Workshop on Recent Advances in Photonics (WRAP) - Guwahati, India (2019.12.13-2019.12.14)] 2019 Workshop on Recent Advances in Photonics (WRAP) - Shadowgraphic Imaging of Cavitation Bubble Dynamics in Pulsed Laser Ablation of a Solid in Liquid
摘要： Insulated-gate bipolar transistor (IGBT) power modules find widespread use in numerous power conversion applications where their reliability is of significant concern. Standard IGBT modules are fabricated for general-purpose applications while little has been designed for bespoke applications. However, conventional design of IGBTs can be improved by the multiobjective optimization technique. This paper proposes a novel design method to consider die-attachment solder failures induced by short power cycling and baseplate solder fatigue induced by the thermal cycling which are among major failure mechanisms of IGBTs. Thermal resistance is calculated analytically and the plastic work design is obtained with a high-fidelity finite-element model, which has been validated experimentally. The objective of minimizing the plastic work and constrain functions is formulated by the surrogate model. The nondominated sorting genetic algorithm-II is used to search for the Pareto-optimal solutions and the best design. The result of this combination generates an effective approach to optimize the physical structure of power electronic modules, taking account of historical environmental and operational conditions in the field.
关键词： fatigue,power cycling (PC),insulated-gate bipolar transistors (IGBTs),thermal cycling (TC),reliability,optimization methods,finite-element (FE) methods,Aging,multiobjective
更新于2025-09-19 17:13:59
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Nondestructive Evaluation of Thermal Aging in Al6061 Alloy by Measuring Acoustic Nonlinearity of Laser-Generated Surface Acoustic Waves
摘要： The structures in high-temperature environments are prone to undergo hardening and embrittlement as a result of thermal aging; this can cause variations in their mechanical properties. Because these changes occur at the microstructural level, it is difficult to evaluate them through linear ultrasonic techniques. In this work, a surface acoustic wave (SAW) was used to measure and compare the acoustic nonlinearity and mechanical properties of Al6061 alloys heat-treated at 220°C for different durations (0 min, 20 min, 40 min, 1 h, 2 h, 10 h, 100 h, 1000 h). The SAW was generated by a pulsed laser and then received by an interferometer. Moreover, the yield strength, ultimate strength, and elongation to failure were measured by tensile tests. The results demonstrate that the critical variations in the mechanical properties can be detected by monitoring the variation features in the acoustic nonlinearity. Transmission electron microscopy images were captured to observe the microstructural changes, which shows that the acoustic nonlinearity varied according to the change in the precipitation phase. This supports the acoustic nonlinearity measurement using the laser-generated SAW being an effective technique for the fully noncontact nondestructive evaluation of material degradations as well as changes in mechanical properties.
关键词： surface acoustic wave,material degradation,laser,heat treatment,mechanical property,thermal aging,nonlinear parameter,precipitation,acoustic nonlinearity
更新于2025-09-19 17:13:59