- 标题
- 摘要
- 关键词
- 实验方案
- 产品
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MODELLING AND SIMULATION OF P-I-N QUANTUM DOT SEMICONDUCTOR SATURABLE ABSORBER MIRRORS
摘要： Semiconductor saturable absorber mirror (SESAM) based on InAs quantum dot (QD) is important in designing fast mode-locked laser devices. A self-consistent time-domain material travelling-wave (TDTW) model for the simulation of self-assembled QD-SESAM is developed. The 1-D TDTW model takes into consideration the time-varying QD optical susceptibility, refractive index variation resulting from the intersubband free-carrier absorption, homogeneous and inhomogeneous broadening. The carrier concentration rate equations are considered simultaneously with the travelling wave model. The model is used to analyze the characteristics of 1.3-μm p-i-n QD InAs-GaAs SESAM. The ?eld distribution resulting from the TDTW equations, in both the SESAM absorbing region and the distributed Bragg re?ectors, is obtained and used in ?nding the device characteristics including the modulation depth and recovery dynamics. These characteristics are studied considering the e?ects of QD surface density, inhomogeneous broadening, the number of QD absorbing layers, and the applied reverse voltage. The obtained results, based on the assumed device parameters, are in good agreement, qualitatively, with the experimental results.
关键词： Travelling-wave model,Quantum dot,Modulation depth,Semiconductor saturable absorber mirror,Recovery dynamics
更新于2025-09-11 14:15:04
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Heat-Recovery Solar Cell
摘要： Heat-recovery (HERC) solar cell—a concept of solar cells utilizing the heat for improving the power conversion e?ciency—is presented. HERC solar cell, characterized by an absorber hotter than electrodes, recovers heat as electricity to have high conversion e?ciency exceeding the detailed balance limit when carrier-energy ?ltering is employed. Being di?erent from hot-carrier solar cells, HERC solar cell does not require fast carrier extraction within the thermalization time, which largely improves its feasibility (feasible even with Si). An increment in the conversion e?ciency originates from thermoelectricity produced by the temperature di?erence. Requirements for materials of the ?ltering layers are also given based on a nonideal device simulation with the thermoelectric properties.
关键词： Si solar cells,Heat-recovery solar cell,carrier-energy filtering,thermoelectricity,power conversion efficiency
更新于2025-09-11 14:15:04
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[IEEE 2018 25th IEEE International Conference on Image Processing (ICIP) - Athens, Greece (2018.10.7-2018.10.10)] 2018 25th IEEE International Conference on Image Processing (ICIP) - Matching Pursuit Based on Kernel Non-Second Order Minimization
摘要： The orthogonal matching pursuit (OMP) is an important sparse approximation algorithm to recover sparse signals from compressed measurements. However, most MP algorithms are based on the mean square error (MSE) to minimize the recovery error, which is suboptimal when there are outliers. In this paper, we present a new robust OMP algorithm based on kernel non-second order statistics (KNS-OMP), which not only takes advantages of the outlier resistance ability of correntropy but also further extends the second order statistics based correntropy to a non-second order similarity measurement to improve its robustness. The resulted framework is more accurate than the second order ones in reducing the effect of outliers. Experimental results on synthetic and real data show that the proposed method achieves better performances compared with existing methods.
关键词： kernel non-second order measurement,correntropy,sparse recovery,Orthogonal matching pursuit
更新于2025-09-11 14:15:04
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A Novel Control Technique for Grid-tied Inverters Considering Unbalanced Grid Voltage Conditions and Control Input Saturation
摘要： This paper presents a new method to design a current controller for grid-tied inverters under both balanced and unbalanced grid voltage conditions. The proposed controller consists of combining feedback-output controller with a disturbance observer (DO). The control design is carried out in the αβ reference frame. Thus, the objective of the composite controller is to ensure that the output of the system tracks a sinusoidal reference signal with zero steady-state error. A feedback controller only cannot achieve a good tracking performance because of the presence of model uncertainties and unknown disturbances. To account for the natural mismatch between the actual system and the mathematical model, the system dynamics is firstly augmented with an additional state-variable, representing the disturbance, and the feedback controller is designed based on the assumption that the disturbance input is available for feedback. Then, an observer is constructed to estimate the disturbance, which is assumed to be a sine wave oscillating at the grid frequency. Another feature of the disturbance observer is its ability to compensate for the effect of the saturation blocks required to limit the control input during transients, leading to improved dynamic performance. Several experimental tests were conducted to verify the effectiveness of the proposed controller, and the results demonstrated its capability to achieve accurate, fast, and stable responses.
关键词： proportional resonant controller,nominal performance recovery,grid-tied inverter,Anti-windup compensator,unbalanced grid voltages,disturbance observer,sinusoidal disturbance rejection
更新于2025-09-11 14:15:04
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[IEEE 2018 20th International Conference on Transparent Optical Networks (ICTON) - Bucharest (2018.7.1-2018.7.5)] 2018 20th International Conference on Transparent Optical Networks (ICTON) - A Proactive Restoration Strategy for Optical Cloud Networks Based on Failure Predictions
摘要： Failure prediction based on the anomaly detection/forecasting is becoming a reality thanks to the introduction of machine learning techniques. The orchestration layer can leverage on this new feature to proactively reconfigure cloud services that might find themselves traversing an element that is about to fail. As a result, the number of cloud service interruptions can be reduced with beneficial effects in terms of cloud service availability. Based on the above intuition, this paper presents an orchestration strategy for optical cloud networks able to reconfigure vulnerable cloud services (i.e., the ones that would be disrupted if a predicted failure happens) before an actual failure takes place. Simulation results demonstrate that, with a single link failure scenario, proactive restoration can lead to up to 97% less cloud services having to be relocated. This result brings considerable benefits in terms of cloud service availability, especially in low load conditions. It is also shown that these improvements come with almost no increase in the cloud service blocking probability performance, i.e., resource efficiency is not impacted.
关键词： Cloud services,Software defined networking (SDN),Availability,Failure prediction,Orchestration,Cloud service relocation,Resiliency,Proactive recovery,Restoration
更新于2025-09-10 09:29:36
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Pixel-Wise MTInSAR Estimator for Integration of Coherent Point Selection and Unwrapped Phase Vector Recovery
摘要： Coherent point (including persistent and distributed scatterers) selection and phase ambiguity treatment (or parameter estimation) are the key tasks involved in multitemporal InSAR (MTInSAR) algorithms, which are usually conducted separately with empirical thresholds. It is not rare to see that due to the discrepancies on threshold setting, even for the same MTInSAR technique with the same data sets, it will raise different (sometimes quite notable) results and affect the applicability of InSAR techniques. We propose here an integrated MTInSAR estimator that combines the coherent point selection and phase vector unwrapping into a single step. Essentially, the estimator aims to recover the unwrapped phase vector at coherent points. Therefore, it could serve as an alternative solution of spatial–temporal phase unwrapping problem. In the estimator, wrapped phase at all pixels in short baseline interferograms are taken as observations. Starting from the phase differences at arcs of a fully connected network of pixels, based on the residual analysis and spatial closure of phase triangularity, the estimator can detect and delete the arcs having unacceptable phase noise and phase ambiguities. By integrating the phase differences at the remained arcs, the unwrapped phase at coherent points in consecutive acquisition intervals can be obtained. Impressively, the estimator is immune to the bias raised by improper deformation model. The performance of the proposed estimator is evaluated via semisynthetic and real data tests. Considering that the phase enhancement algorithms (e.g., phase-linking and Extended Minimum Cost Flow-Small BAseline Subset) that can reconstruct high-quality wrapped phases are gaining popularity, the proposed estimator can also be implemented as a postprocessing module of these algorithms for retrieval of unwrapped phase vectors at coherent points.
关键词： phase unwrapping,phase recovery,InSAR (MT-InSAR),consistency,Ambiguity detection,coherent points detection
更新于2025-09-10 09:29:36
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A power scalable 2–10?Gb/s PI-based clock data recovery for multilane applications
摘要： This paper presents a power scalable clock data recovery (CDR) suitable for multilane and multirate applications. To make the power consumption scale with the data rate and guarantee appropriate edge overlaps for the phase interpolation, a delay-locked loop-based global biasing strategy is proposed to automatically adjust the bandwidth of the current-mode logic buffers and phase interpolator (PI). The I, Q clocks are generated by a local clock conditioner, which employs an open-loop voltage-controlled delay line to produce the evenly spaced multiple phases and adopts a two-stage timing averaging to correct the duty cycle distortion and I, Q mismatch. Additionally, a phase-compensating technique is adopted in the PI to optimize its linearity. Implemented in a 65-nm CMOS process with an area occupation of 0.12 mm2, the presented CDR can operate from 2 to 10 Gb/s with a scalable power consumption from 11 to 42 mW. When it operates at 10 Gb/s, the maximum tolerable amplitude of the sinusoidal jitter at 50 MHz is 0.52 UIpp, and the total jitter of the recovered clock is 16.6 ps at a BER of 1e-12.
关键词： Clock data recovery (CDR),Timing averaging (TA),Local clock conditioner,Voltage-controlled delay line (VCDL),Power scaling,Phase interpolator (PI),Global biasing strategy
更新于2025-09-10 09:29:36
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Rapid Self-healing Film From Novel Photo Polymerization Additive.
摘要： Self-healing materials have ability to repair damage by themselves. Their properties have been developed to increase the reliability of materials. Generally, self-healing polymers have been developed by thermal polymerization. Especially, hydrogel materials showed relatively rapid recovery and good-healing efficiency. However, it is very difficult to restore their properties without the self-healing mediator such as water. Herein, we report the novel type of self-healing polymer using photo-polymerization. This is achieved through an unprecedented concept of an additive of photopolymerization, named as ‘healer’ which can act as a physical crosslinker between main chains and a self-healing mediator in hydrogel materials. This transparent, easily fabricated self-healing polymer healed scratch in 40 seconds as well as restored the mechanical properties to 82%.
关键词： Self-healing properties,Supramolecular chemistry,Scratch recovery,Photo-polymerization,Polymers
更新于2025-09-10 09:29:36
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Potentiality of zinc oxide nanosensor prepared by a new electroplating method on p-Si (1?1?1) wafer substrate
摘要： Nanostructured ZnO thin films were deposited on p-Si (1 1 1) substrates using a new electrodeposition method. Electrical and sensing properties were investigated. Variations of the resistance measured between two points of the ZnO film, have shown a maximum sensitivity (d = 10) in the presence of gas ?CO? and (d = 14,70) in the presence of ?C2H5OH? at a temperature of 300 (cid:1)C. Therefore, we can say that the sensitivity tests indicate that the sensor consisting of a nanometer zinc oxide layer is more efficient at temperatures beyond 100 (cid:1)C. Moreover, the sensing element has demonstrated a good response to reducing gases species.
关键词： Sensitivity,ZnO,Ethanol/carbon monoxide sensor,Electrodeposition,Response/recovery times
更新于2025-09-10 09:29:36
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[IEEE 2018 25th IEEE International Conference on Image Processing (ICIP) - Athens, Greece (2018.10.7-2018.10.10)] 2018 25th IEEE International Conference on Image Processing (ICIP) - Closed-Form Solution of Simultaneous Denoising and Hole Filling of Depth Image
摘要： This paper presents a novel Time-of-Flight (ToF) depth recovery algorithm minimizing a new quadratic energy function utilizing depth and infrared data. The proposed energy function consists of a filtering term and a reconstruction term to remove noise and fill holes simultaneously in a depth image. In the filtering term, a new multilateral weight is introduced by fully using available spatial, depth, and infrared information. In the reconstruction term, a Poisson equation for reconstructing a depth image from its gradients is used whereas the depth gradients inside hole regions are interpolated with the proposed infrared-guided moving least squares. The recovered depth data can be obtained by solving a sparse linear system derived from minimizing the proposed energy function. Experimental results demonstrate that the proposed algorithm provides good depth recovery performance without introducing texture copy or blur artifacts compared to the existing methods.
关键词： hole filling,inpainting,time-of-flight depth,denoising,quadratic energy function,Depth recovery
更新于2025-09-10 09:29:36