- 标题
- 摘要
- 关键词
- 实验方案
- 产品
过滤筛选
- 2019
- 2018
- 2017
- 2016
- Optical pattern
- Phase diagram
- Surfactants
- Optical properties
- TB-MBJ
- FP-LAPW
- Electronic structure
- GGA
- DFT
- Infrared Radiation
- Optoelectronic Information Science and Engineering
- Chemistry
- Materials Science and Engineering
- University of Texas at Arlington
- Macquarie University
- Universiti Malaysia Terengganu
- Devi Ahilya University
- National Institute of Information and Communications Technologies (NICT)
- Povolzhskiy State University of Telecommunications and Informatics (PSUTI)
- University of Sa?da Dr Tahar Moulay
- University of Djillali Liabes
- Assumption University
- National Institute of Advanced Industrial Science and Technology
-
Amplification of the Zeroth Order Mode in Ultra-thin Layers
摘要： The ultra-thin limit regime is characterized by a structure which at least in one dimension is signi?cantly smaller than the incoming light wavelength. The absorption in this regime is characterized either by very weak absorption or by a broad peak attributed to the zeroth order Fabry-Perot mode. We show that this mode provides a 14.5% ultimate ef?ciency in a 25 nm GaAs slab on a gold substrate. GaAs in air achieves only a 5% for a 10 nm slab. Such an ampli?cation of the resonance absorption is attributed to the high losses of the substrate. For very high losses, the zeroth order mode transits from an over-damped regime to an under-damped one.
关键词： absorption,Solar cells,optical coating,quasinormal modes,optics
更新于2025-09-23 15:23:52
-
Métodos para a tomada de decis?o em portfólio de produtos: um levantamento em empresas dos setores eletr?nico, óptico e de informática
摘要： Decision making in product portfolio is a relevant aspect, not only to the good performance of product development, but also to support in the process of business strategy. This article has the objective to present and analyze the main methods for decision making in product portfolio used by large and medium enterprises that operate in Brazil, in electronic, optical and computer sectors. A survey research was conducted in a sample of 40 companies. It was noted, that most of these companies, especially the middle sized companies, followed an informal pattern for decision-making in product portfolio, which is guided, mainly, by the perception of senior management. Among the employed formal methods, financial, market research and mapping methods are the most present in the surveyed sectors.
关键词： Process of Product Development,Survey research,Methods for Decision Making,Product Portfolio Management,Electronic, optical and computing companies
更新于2025-09-23 15:23:52
-
Performance Limits of FSO Based SAC-OCDMA System Under Weather Conditions
摘要： In this paper, the Spectral Amplitude Coding Optical Code Division Multiple Access (SAC-OCDMA) is investigated in Free Space Optics (FSO) using Zero Cross Correlation (ZCC) codes to evaluate its performance limits in terms of link range. The system is analyzed under clear, haze, moderate fog and dense fog weather conditions. This system has been evaluated numerically and by simulation analysis by maintaining the transmitted power at 10 dBm, for safety reason, according to International Telecommunication Union (ITU) and minimum acceptable BER of 10–9. The simulation results shown that the present system can transmit 622 Mbps/1 Gbps up to maximum link range of 1450 m/1100 m and 61 m/54 m under clear and dense fog conditions, respectively.
关键词： fog,haze,free space optic (FSO),spectral amplitude coding optical code division multiple access (SAC-OCDMA),zero cross-correlation (ZCC)
更新于2025-09-23 15:23:52
-
Geometric Calibration of Markerless Optical Surgical Navigation System
摘要： Background: Patient-to-image registration is required for image-guided surgical navigation, but marker-based registration is time consuming and subject to manual error. Markerless registration is an alternative solution to avoid these issues. Methods: This study designs a calibration board and proposes a geometric calibration method to calibrate the near infrared tracking and structured light components of the proposed optical surgical navigation system simultaneously. Results: A planar board and a cylinder are used to evaluate the accuracy of calibration. The mean error for the board experiment is 0.035 mm, and the diameter error for the cylinder experiment is 0.119 mm. A calibration board is reconstructed to evaluate the accuracy of the calibration, and the measured mean error is 0.012 mm. A head phantom is reconstructed and tracked by the proposed optical surgical navigation system. The tracking error is less than 0.3 mm. Conclusions: Experimental results show that the proposed method obtains high accessibility and accuracy and satisfies application requirements.
关键词： Calibration,Markerless,Structure light,Optical surgical navigation system
更新于2025-09-23 15:23:52
-
[IEEE 2018 IEEE International Conference on Computer and Communication Engineering Technology (CCET) - Beijing, China (2018.8.18-2018.8.20)] 2018 IEEE International Conference on Computer and Communication Engineering Technology (CCET) - Elastic Optical Network Spectrum Fragmentation Algorithm
摘要： Aiming at spectrum allocation problem in elastic optical networks, a spectrum allocation method that combines the advantages of genetic algorithm and ant colony algorithm is proposed. This method uses genetic algorithm to generate the initial solution with rapid random population global search ability. Then the initial solution of the genetic algorithm is transformed into the initial distribution of pheromone required by the ant colony algorithm using the cohesion strategy. Finally, the positive feedback and efficient convergence of the ant colony algorithm are used. Features Find the optimal solution and provide a solution for improving network efficiency
关键词： Network Spectrum,Elastic Optical Network,Fragmentation Algorithm
更新于2025-09-23 15:23:52
-
Photo-Optical <i>In-Situ</i> Measurement of Drop Size Distributions: Applications in Research and Industry
摘要： The exact knowledge of Drop Size Distributions (DSD) plays a major role in various fields of applications to control and optimise processes as well as reduce waste. In the microbial production of advanced biofuels, oil droplets are produced under turbulent conditions in an aqueous medium containing many surface active components, which might hinder the recovery of the product. Knowledge of DSD is thus essential for process optimisation. This study demonstrates the capability of a photo-optical measurement method for DSD measurement in fermentation broth and in plate separators aimed at cost reduction in the microbial production of advanced biofuels. Measurements were made with model mixtures in a bioreactor, and at the inlet and outlet of a plate separator. In the bioreactor, the method was effective in detecting a broad range of droplet sizes and in differentiating other disperse components (e.g. microbial cells and gas bubbles). In the plate separator, the method was effective in determining the influence of the varied parameters on the separation efficiency.
关键词： biofuels,in-situ measurement,fermentation broth,Drop Size Distributions,plate separator,photo-optical measurement
更新于2025-09-23 15:23:52
-
Performance of Bandwidth Extension Techniques for High-Speed Short-Range IM/DD Links
摘要： In recent years, advanced modulation formats for short-range high-speed communications have been increasingly discussed to achieve the transmission rates needed to satisfy the future demand of broadband services. A key parameter in such applications is the use of low-cost optical components, which mainly means the use of intensity modulation (IM) and direct detection (DD) schemes. In order to exploit the available bandwidth offered by the latest optical components, high-speed data converters (DAC and ADC) are required. However, the available bandwidth of DACs and ADCs is generally smaller, than that of their optical counterparts, resulting in a capacity bottleneck. This issue can be addressed by bandwidth extension techniques, which enable the full use of the optical components. In this paper, two high-speed systems are presented and experimentally analyzed for an optical link based on IM/DD, utilizing a bandwidth extension technique based on electrical up/down-conversion and passive signal combining. The experiment for the first system uses two independent sub-signals, with a total bandwidth beyond 40 GHz and enables transmission rates up to 180 Gb/s. Different aspects of the system are highlighted including general performance, transmission distance, use of different modulation formats and the influence of important components. For the second system, the experiment consists of the generation of a spectrally continuous pulse amplitude modulation (PAM) signal with the help of two sub-signals and its transmission over an optical IM/DD link. The challenges and requirements for hardware and software are discussed and the impact of power and phase mismatches between both sub-signals are investigated as well.
关键词： Fiber optics and optical communications,Fiber optics links and subsystems
更新于2025-09-23 15:23:52
-
Passive Sub-Carrier Multiplexing for Discriminating Overlapped Optical Spectra
摘要： A passive technique for multiplexing spectrally overlapping optical network signals is proposed and experimentally verified. The system utilizes arrayed fiber delay lines for multiplexing signal generation and offers simultaneous plotting of multiple optical spectra. Accurate recovery of individual spectrum of multiplexed long-period gratings spectra is experimentally demonstrated in a refractive index sensing application. This system provides an all-optical platform for economical multiplexing system in optical sensing networks.
关键词： Multiplexing scheme,optical sensor network,temporal shifting
更新于2025-09-23 15:23:52
-
Human activity recognition via optical flow: decomposing activities into basic actions
摘要： Recognizing human activities using automated methods has emerged recently as a pivotal research theme for security-related applications. In this research paper, an optical flow descriptor is proposed for the recognition of human actions by considering only features derived from the motion. The signature for the human action is composed as a histogram containing kinematic features which include the local and global traits. Experimental results performed on the Weizmann and UCF101 databases confirmed the potentials of the proposed approach with attained classification rates of 98.76% and 70%, respectively, to distinguish between different human actions. For comparative and performance analysis, different types of classifiers including Knn, decision tree, SVM and deep learning are applied to the proposed descriptors. Further analysis is performed to assess the proposed descriptors under different resolutions and frame rates. The obtained results are in alignment with the early psychological studies reporting that human motion is adequate for the perception of human activities.
关键词： Optical flow,Motion descriptor,Action recognition,Decomposing activities
更新于2025-09-23 15:23:52
-
Dense Descriptors for Optical Flow Estimation: A Comparative Study
摘要： Estimating the displacements of intensity patterns between sequential frames is a very well-studied problem, which is usually referred to as optical flow estimation. The first assumption among many of the methods in the field is the brightness constancy during movements of pixels between frames. This assumption is proven to be not true in general, and therefore, the use of photometric invariant constraints has been studied in the past. One other solution can be sought by use of structural descriptors rather than pixels for estimating the optical flow. Unlike sparse feature detection/description techniques and since the problem of optical flow estimation tries to find a dense flow field, a dense structural representation of individual pixels and their neighbors is computed and then used for matching and optical flow estimation. Here, a comparative study is carried out by extending the framework of SIFT-flow to include more dense descriptors, and comprehensive comparisons are given. Overall, the work can be considered as a baseline for stimulating more interest in the use of dense descriptors for optical flow estimation.
关键词： feature descriptors,optical flow estimation,dense descriptors
更新于2025-09-23 15:23:52