- 标题
- 摘要
- 关键词
- 实验方案
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Slab RF-discharge carbon dioxide laser with active mode-locking
摘要： Mode-locking with an acousto-optic modulator was for the first time demonstrated for a repetitively pulsed (150 Hz) slab RF discharge CO2 laser. The mode-locked CO2 laser emitted trains of 5.5 ns pulses following with 27.25 MHz repetition rate. Mode-locking also affected the laser pulses envelope in respect to free-runing mode. The numerical estimation of the laser system scalability indicated an opportunity to develop a very compact CO2 laser emitting sub-nanosecond pulses.
关键词： slab design,mode-locking,RF discharge,CO2 laser,nanosecond pulse
更新于2025-09-23 15:19:57
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High sensitivity sensing system theoretical research base on waveguide-nano DBRs one dimensional photonic crystal microstructure
摘要： In this paper, we propose a novel wavelength modulation system dedicated to improve the performance of the integrated silicon microsensor. This system includes light source, waveguide, distributed Bragg reflectors (DBRs) and optical spectrum analyzer. Here, the silicon waveguide and two nano DBRs were designed to be one dimensional photonic crystal structure, which can implement wider modulation range in the photonic band gap. The rigorous coupled wave analysis (RCWA) method was used to quantitatively calculate transmissivity of each wavelength photon, and then spectral data in different displacement were obtained. By analyzing the defect modes in the spectrum, typical performance indicators of this modulation system are demonstrated as follows: The wavelength defect mode can be modulated from 1.2 μm to 2.7 μm, corresponding displacement is from 0 to 1.5 μm; System sensitivity is up to 1.23-1.41, linearity ranges from 0.99 to 0.9999 for order 1 defect mode; The minimum peak transmittance of defect mode is greater than 0.68 based on 1 pm wavelength calculated step. Compared with the same type of system reported, the performance indicators have obvious advantages, and it is expected to directly improve the sensor performance by combining with the existing micro-mechanical structure.
关键词： Optical instruments,Optical spectrum analysis,Optical systems,Optical design of instruments
更新于2025-09-23 15:19:57
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Rate Equation Modeling of Interband Cascade Lasers on Modulation and Noise Dynamics
摘要： An intelligent hybrid Taguchi-genetic algorithm (IHTGA) is used to optimize bearing offsets and shaft alignment in a marine vessel propulsion system. The objectives are to minimize normal shaft stress and shear force. The constraints are permissible reaction force, bearing stress, shear force, and bending moment in the shaft thrust ?ange under cold and hot operating conditions. Accurate alignment of the shaft for a main propulsion system is important for ensuring the safe operation of a vessel. To obtain a set of acceptable forces and stresses for the bearings and shaft under operating conditions, the optimal bearing offsets must be determined. Instead of the time-consuming classical local search methods with some trial-and-error procedures used in most shipyards to optimize bearing offsets, this paper used IHTGA. The proposed IHTGA performs Taguchi method between the crossover operation of the conventional GA. Incorporating the systematic reasoning ability of Taguchi method in the crossover operation enables intelligent selection of genes used to achieve crossover, which enhances the performance of the IHTGA in terms of robustness, statistical performance, and convergence speed. A penalty function method is performed using the ?tness function as a pseudo-objective function comprising a linear combination of design objectives and constraints. A ?nite-element method is also used to determine the reaction forces and stresses in the bearings and to determine normal stresses, bending moments, and shear forces in the shaft. Computational experiments in a 2200 TEU container vessel show that the results obtained by the proposed IHTGA are signi?cantly better than those obtained by the conventional local search methods with some trial-and-error procedures.
关键词： bearing offsets,optimal design,Marine vessel propulsion system,shaft alignment,genetic algorithm
更新于2025-09-23 15:19:57
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[IEEE 2019 6th International Conference on Systems and Informatics (ICSAI) - Shanghai, China (2019.11.2-2019.11.4)] 2019 6th International Conference on Systems and Informatics (ICSAI) - An electromagnetic and piezoelectric coupled energy harvester using cantilever beam for low frequency vibration
摘要： With the emergence of the Microsoft Kinect sensor, many developer communities and research groups have found countless uses and have already published a wide variety of papers that utilize the raw depth images for their specific goals. New methods and applications that use the device generally require an appropriately large ensemble of data sets with accompanying ground truth for testing purposes, as well as accurate models that account for the various systematic and stochastic contributors to Kinect errors. Current error models, however, overlook the intermediate infrared (IR) images that directly contribute to noisy depth estimates. We, therefore, propose a high fidelity Kinect IR and depth image predictor and simulator that models the physics of the transmitter/receiver system, unique IR dot pattern, disparity/depth processing technology, and random intensity speckle and IR noise in the detectors. The model accounts for important characteristics of Kinect’s stereo triangulation system, including depth shadowing, IR dot splitting, spreading, and occlusions, correlation-based disparity estimation between windows of measured and reference IR images, and subpixel refinement. Results show that the simulator accurately produces axial depth error from imaged flat surfaces with various tilt angles, as well as the bias and standard lateral error of an object’s horizontal and vertical edge.
关键词： simulation,Computer-aided design (CAD),Microsoft Kinect,infrared (IR) dot pattern,structured-light 3-D scanner,speckle noise
更新于2025-09-23 15:19:57
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Deep Learning for the Inverse Design of Mid-Infrared Graphene Plasmons
摘要： We theoretically investigate the plasmonic properties of mid-infrared graphene-based metamaterials and apply deep learning of a neural network for the inverse design. These artificial structures have square periodic arrays of graphene plasmonic resonators deposited on dielectric thin films. Optical spectra vary significantly with changes in structural parameters. To validate our theoretical approach, we carry out finite difference time domain simulations and compare computational results with theoretical calculations. Quantitatively good agreements among theoretical predictions, simulations, and previous experiments allow us to employ this proposed theoretical model to generate reliable data for training and testing deep neural networks. By merging the pre-trained neural network with the inverse network, we implement calculations for inverse design of the graphene-based metameterials. We also discuss the limitation of the data-driven approach.
关键词： inverse design,plasmonics,deep learning,graphene,metamaterials
更新于2025-09-23 15:19:57
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Approaches to The Hagfeldt Donor and Use of Next Generation Bulky Donor Designs in Dyea??Sensitized Solar Cell Dyes
摘要： 'The Hagfeldt donor' is a bulky triarylamine building block with 4 alkyl chains in a 3-dimensional arrangement which is used with organic dyes in dye-sensitized solar cells (DSCs) in over 140 manuscripts. Many of the highest performing DSC devices in literature make use of this group due to exceptional TiO2 surface protection properties which slows recombination of electrons in TiO2 with the electrolyte. Importantly, record-setting cobalt and copper redox shuttle based-DSCs require exceptional surface protection to slow a facile recombination of electrons to these positively charged redox shuttles. Several syntheses have emerged for the Hagfeldt donor due to the need for iterative aryl-halide cross couplings complicating a straight forward route. The six synthetic strategies found in literature are described along with the challenges of each route. A recent method that has been put forward in the literature as a scalable, regioisomerically pure route is highlighted.
关键词： dye design,masked halide,dye-sensitized solar cells,low recombination functionality,Hagfeldt donor
更新于2025-09-23 15:19:57
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Biomimetic design and laser additive manufacturinga??A perfect symbiosis?
摘要： Biomimetics as well as additive manufacturing have prominently produced novel design approaches for parts and products independently from each other. The combination of both has resulted in numerous innovative part designs that were unseen before. However remarkable the marketing impact of individual 3D printed biomimetic parts has been, a widespread industrial application is missing to date. This publication, therefore, takes a closer look at how biomimetic design in additive manufacturing is currently pursued and evaluates the different design approaches based on their suitability for industrial application. The assessment reveals that algorithms and thesaurus tools should be preferred in an industrial biomimetic design process. From the various additive manufacturing methods, laser additive manufacturing today is a dominating industrial application when it comes to metal parts. Thus, several case studies of biomimetic designs produced with laser additive manufacturing are presented. On the basis of the selected examples, the added value through biomimetic design is discussed and reviewed critically, raising the question of when a biomimetic design approach is promising compared to conventional design approaches. Based on the review of current use cases and the potentials that the combination of biomimetics and additive manufacturing offer, recommended fields of research are concluded. Finally, the road to industry for biomimetic additive manufacturing design is outlined, taking into account the findings on existing biomimetic design methodologies and tools.
关键词： laser additive manufacturing,biomimetic design,3D printing
更新于2025-09-23 15:19:57
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Recent Progress in Chlorinated Organic Photovoltaic Materials
摘要： Over the past few years, the development of new materials has contributed to rapid increases in the power conversion efficiencies (PCEs) of organic photovoltaic (OPV) cells to over 17%, showing great potential for the commercialization of this technology in the near future. At this stage, designing new materials with superior performance and low cost simultaneously is of crucial importance. Chlorinated materials are emerging as new stars with very high PCEs, creating a molecular design trend to replace the most popular fluorinated materials. For example, by using chlorinated non-fullerene acceptors, we recently got a record PCE of 17% for single-junction OPV cells. Firmly based on recent advances, herein we focus on the topic of chlorinated OPV materials, aiming to provide a guideline for further molecular design.
关键词： chlorinated materials,organic photovoltaic cells,power conversion efficiencies,non-fullerene acceptors,molecular design
更新于2025-09-23 15:19:57
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Evaluating economic feasibility and maximization of social welfare of photovoltaic projects developed for the Brazilian northeastern coast: An attribute agreement analysis
摘要： Recently, renewable energy projects, such as photovoltaic systems, have become interesting generation alternatives thanks to the incentive strategies developed by several countries. For the user of photovoltaic microgeneration, there is interest in the financial return of the investment, which is most often financed by public banks with a limited budget. Therefore, it is necessary to analyze variables related both to the point of view of the investor in microgeneration and to the public banks that subsidize them. However, defining the configuration of photovoltaic systems that guarantees the economic feasibility for those who invest without excessively burdening the public resource is a complex task and requires the analysis of different experts. To fill this gap, this paper proposes an innovative approach for evaluating photovoltaic projects based on Attribute Agreement Analysis. Experts on photovoltaic systems with different profiles and experience were asked about 16 scenarios, planned according to a factorial design with four factors: installed power capacity, PV cell type, debt ratio, and loan interest rate. The results demonstrated that the proposed approach fulfills the objective of simultaneously assessing the impact of investments in photovoltaic systems, considering the investors’ and public banks’ viewpoints. In the case analyzed, although the evaluations are performed in a judicious way (Wwithin> 0.85), there is a low agreement between the experts (Woverall < 0.70). In addition, an expert bias was observed regarding loan interest for economic feasibility (W ? 0.61), as well as a controversial perception of the maximization of social welfare (W ? 0.2361). The Net Present Value profile, determined by the installed power capacity of the system, was used with these results to discuss the current Brazilian renewable energy financing policy. The results supported that experts tend to overestimate the impact of the financing interest rate on financial returns.
关键词： Social welfare,Factorial design,Attribute agreement analysis,PV microgeneration,Economic feasibility
更新于2025-09-23 15:19:57
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[IEEE 2018 IEEE International Conference on Computational Electromagnetics (ICCEM) - Chengdu (2018.3.26-2018.3.28)] 2018 IEEE International Conference on Computational Electromagnetics (ICCEM) - Frequency-Dependent Implicit Space-Mapping Algorithm for Wideband Microwave Prototyping
摘要： In this paper, a frequency-dependent implicit space mapping method is proposed for the prototyping of wideband microwave device. In the proposed method, frequency-dependent mapping is established between the fabricated device and a fast surrogate model. In this way, the practical variance of electromagnetic properties in a wide frequency range can be properly approximated. The parameter extraction process fabrication can be becomes more reliable, significantly reduced. To verify the proposed method, a wide-band impedance transformer is fabricated and tested as an example. The testing results achieve design specification within only two fabrications.
关键词： space mapping,microwave design,optimization
更新于2025-09-23 15:19:57