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Metrology Data-Based Simulation of Freeform Optics
摘要： This paper describes the approach to use measurement data to enhance the simulation model for designing freeform optics. Design for manufacturing of freeform optics is still challenging, since the classical tolerancing procedures cannot be applied. In the case of spherical optics manufacturing, tolerances are more or less isotropic, and this relationship is lost in case of freeform surfaces. Hence, an accurate performance prediction of the manufactured optics cannot be made. To make the modeling approach as accurate as possible, integration of measured surface data of fabricated freeform optics in the modeling environment is proposed. This approach enables performance prediction of the real manufactured freeform surfaces as well as optimization of the manufacturing process. In our case study this approach is used on the design of an Alvarez-optics manufactured using a microinjection molding (μIM) process. The parameters of the μIM process are optimized on the basis of simulation analysis resulting in optics, with a performance very close to the nominal design. Measurement of the freeform surfaces is conducted using a tactile surface measurement tool.
关键词： systems design,simulation,form measurements,3D measurements
更新于2025-09-09 09:28:46
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[IEEE 2018 IEEE XXVII International Scientific Conference Electronics (ET) - Sozopol, Bulgaria (2018.9.13-2018.9.15)] 2018 IEEE XXVII International Scientific Conference Electronics - ET - Shieldless Eddy-Current Displacement Sensor with Improved Measurement Sensitivity
摘要： The major limitations of eddy-current displacement sensors, such as low measurement sensitivity and low stability, can be mitigated by using low-inductance flat coils in combination with a ratiometric measurement and a high excitation frequency, thus making eddy-current sensors of interest for high-precision applications. For the ratiometric measurement, the sensing coil is used in combination with a constant inductance reference coil, which are magnetically isolated from each other by a shield. In this paper, the implications of omitting the shield are studied. It is shown that a shieldless design brings several advantages related to sensitivity, compactness and manufacturability.
关键词： eddy-current sensor,magnetic shielding,displacement sensing,ratiometric measurement,sensor design
更新于2025-09-09 09:28:46
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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) - Structuring of Magnetic Nanoparticle Fluids for Decorative and Functional Printing and Coating
摘要： Printing and coating of magnetic inks is widely used in the field of magnetic barcode labels. Nanoparticle inks have gained increasing interest in the field of printed electronics. Controlling the transport of magnetic nanoparticle fluids by external magnetic fields is nowadays mainly applied in environmental and biomedical research, e.g. in order to transport functionalised magnetic particles for drug delivery, sensing, thermal cancer therapy, or for the extraction of pollutants in waste water cleaning. Application examples of field assisted nanoparticle assembly or fluid control in coating and printing, e.g. for the structural colour generation in photonics, are recently emerging. In this paper, we address the topic of field assisted patterning by the design of a versatile magnetic pattering and structuring platform for field assisted nanoparticle assembly and locally tailored pattern formation in printing and thin film coating. 2D finite element modelling for tailored magnetic field patterning, as well as experimental inkjet printing and coating results for Fe2O3 iron oxide nanoparticles on glass are presented and discussed. The developed print patterning technique is of interest for decorative and functional printing and coating, e.g. for further developments in the application field of smart security tags.
关键词： superparamagnetic nanoparticles,coating,patterning system design,inkjet printing,nanoparticle inks,field assisted patterning
更新于2025-09-09 09:28:46
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[IEEE 2018 IEEE 3rd Optoelectronics Global Conference (OGC) - Shenzhen, China (2018.9.4-2018.9.7)] 2018 IEEE 3rd Optoelectronics Global Conference (OGC) - Domestically Designed Integrated Silicon-Based Module for Coherent Optical Transmission Network
摘要： A line card with low power silicon-based module is demoed on current commercial network by Shanghai Telcom. This is China’s first domestically designed silicon-based module in coherent transmission systems. This module has an excellent performance. All key parameters passed the test requirements of Nx100Gbit/s optical wavelength division multiplexing systems and shows a more than 6-watt power consumption reduction.
关键词： silicon photonics,inhouse design,coherent optical transmission network
更新于2025-09-09 09:28:46
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Coupling Pulsed Flying Spot technique with robot automation for industrial thermal characterization of complex shape composite materials
摘要： In a previous work we developed methods based on Pulsed Flying Spot (PFS) to measure the in-plane thermal diffusivity of (an)isotropic materials. Due to the optical laser scanning system, the effective measurement area is around 5 cm x 5cm) to obtain a good spatial resolution and to ensure accurate estimated thermal fields. First, to extend the previous method to largest scanning area, we propose to use a robotic arm to analyse large composite samples of complex shape (more than 50 cm x 50 cm). The main advantage of using the robot is to design by Computer Aided Design the complete geometry of the composite sample in order to scan the complete area of the composite and also to orient the non-plane surface of the sample perpendicular to the IR camera field of view and laser spot. Finally, all the area can be thermally characterized and the retrieved in plane thermal diffusivities maps are pasted on the 3D shape to visualise heterogeneity and anisotropy.
关键词： thermal diffusivity,robotic arm,Pulsed flying spot,computer aided design
更新于2025-09-09 09:28:46
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Computer-Aided Panoramic Images Enriched by Shadow Construction on a Prism and Pyramid Polyhedral Surface
摘要： The aim of this study is to develop an efficient and practical method of a direct mapping of a panoramic projection on an unfolded prism and pyramid polyhedral projection surface with the aid of a computer. Due to the fact that straight lines very often appear in any architectural form we formulate algorithms which utilize data about lines and draw panoramas as plots of functions in Mathcad software. The ability to draw panoramic images of lines enables drawing a wireframe image of an architectural object. The application of the multicenter projection, as well as the idea of shadow construction in the panoramic representation, aims at achieving a panoramic image close to human perception. The algorithms are universal as the application of changeable base elements of panoramic projection—horizon height, station point location, number of polyhedral walls—enables drawing panoramic images from various viewing positions. However, for more efficient and easier drawing, the algorithms should be implemented in some graphical package. The representation presented in the paper and the method of its direct mapping on a flat unfolded projection surface can find application in the presentation of architectural spaces in advertising and art when drawings are displayed on polyhedral surfaces and can be observed from multiple viewing positions.
关键词： polyhedra,panoramic projection,shadow construction,Computer Aided Design (CAD),maps on surfaces,descriptive geometry
更新于2025-09-09 09:28:46
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Resource optimization of optical aggregation network for efficient software-defined datacenters
摘要： Software-defined datacenters (SDDCs) have recently received much attention for rapid delivery of cloud-based applications. In this paper, we consider the design of an optical aggregation network for cost-efficient software-defined datacenters (SDDCs). Here, an optical aggregation network connects a server accommodating virtual network functions (VNFs) with access gateway nodes (AGNs) via a time-division-multiplexing (TDM)-based point-to-multipoint (P2MP) wavelength path to aggregate traffic from geographically distributed end users to cloud datacenters. Each VNF must be placed on an adequate server in consideration of the efficiency of wavelength paths to reduce network cost for cloud access. However, existing VNF placement algorithms determine VNF placement without considering the efficiency of P2MP wavelength paths, which deteriorates network performance and increases network cost. To solve this problem, VNFs must be placed so that a P2MP wavelength path can be efficiently shared by multiple AGNs to reduce network cost. For this purpose, we propose a VNF placement algorithm, called the decomposition-based VNF placement algorithm (DVA), in a TDM-wavelength-division-multiplexing (WDM)-based optical aggregation network for cost-efficient SDDCs. DVA can find approximate solutions of sufficient quality within practical computation time.
关键词： network optimization,VNF placement,aggregation network,network design,NFV
更新于2025-09-09 09:28:46
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Alternative designs of parabolic trough solar collectors
摘要： Parabolic trough collector (PTC) is the most established solar concentrating technology worldwide. The conventional parabolic trough collectors are used in various applications of medium and high-temperature levels. However, there are numerous studies which investigate alternative designs. The reasons for examining different PTC configurations regard the thermal efficiency increase, the reduction of the manufacturing cost and the development of more compact designs. The objective of this review paper is to summarize the existing alternative designs of PTC and to suggest the future trends in this area. Optical and thermal modifications are examined, as well as the use of concentrating thermal photovoltaic collectors. The optical modifications include designs with secondary concentrators, stationary concentrators and strategies for achieving uniform heat flux. The thermal modifications regard the use of nanofluids, turbulators and the use of thermally modified receivers with insulation, double-coating and radiation shields. The concentrating thermal photovoltaics are systems with flat or triangular receivers which can operate in low or in medium temperature levels with the proper alternative designs. It has been found that there are many promising choices for designing PTC with higher thermal performance and lower cost. The conclusions of this work can be used as guidelines for future trends in linear parabolic concentrating technologies.
关键词： Nanofluids,Solar energy,Alternative design,Secondary reflector,Parabolic trough collector,Thermal enhancement
更新于2025-09-09 09:28:46
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Optical Filter Designs for Multi-Color Visible Light Communication
摘要： In visible light communication (VLC), using multiple colors is an efficient way to enhance data rate, leading to multi-color VLC (MC-VLC). However, the performance of MC-VLC is jeopardized by the spectral overlaps of different colors. Thin-film optical filters, as the key component of MC-VLC systems, are usually adopted to separate colors. The passband bandwidth (BW) and center wavelength (CWL) of optical filters are critical to mitigate the crosstalk among colors, and thus must be carefully designed. Moreover, due to the intrinsic wavelength shift of the CWL with the varying of the angle of incidence (AoI), it is challenging to support mobility for MC-VLC. In this paper, we consider a joint design of multiple optical filters for MC-VLC by properly selecting the BW and CWL of each filter. We first investigate the optical filter design for a fixed receiver location. Then, to support mobility, we propose two robust optical filter designs, namely statistically and worst-case robust designs, which do not rely on the exact receiver location. Efficient methods are developed to solve the corresponding design problems and obtain the optimized optical filters. Compared with the existing optical filters, the proposed optical filters exhibits much better performance in various scenarios.
关键词： robust design,optical filter,spectrum shift,Mobility,multi-color LED,visible light communication,spectral overlap
更新于2025-09-09 09:28:46
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Characterization of additively manufactured cellular alumina dielectric structures
摘要： Additive manufacturing (AM, also known as 3D printing) can produce novel three-dimensional structures using low-loss dielectric materials. This enables the construction of dielectrics with complex shapes that enable innovative microwave applications such as resonators, filters, and metamaterial lenses. This paper addresses the production and characterization of cellular structures of various designed densities created with a low loss ceramic material, alumina (aluminum oxide), via vat photopolymerization. The permittivity of these printed structures is variable over roughly an octave, with a range of relative permittivites from 1.78 to 3.60, controlled via part geometry.
关键词： electromagnetic metamaterials,dielectric materials,ceramics,printing,design for manufacture
更新于2025-09-09 09:28:46