- 标题
- 摘要
- 关键词
- 实验方案
- 产品
-
Contact Lenses || Optics and Lens Design
摘要： Some aspects of contact lens design and optics are rarely applied nowadays, as they are less relevant to modern practice, but readers may still need to refer to them. They are available at: https://expertconsult.inkling.com/, whereas the more relevant topics are included here. The appendix, available at: https://expertconsult.inkling.com/, also describes various equations that are used in contact lens work, while the online resources include programs relating to both the optics and to lens design. There are two main aspects to be considered when dealing with the optics of contact lenses: the effects on the wearer of the optical differences from spectacles and the necessity for the practitioner to understand the components which affect the back vertex power (BVP) of the contact-lens/liquid*-lens system. There is some overlap of these two aspects, but for the sake of convenience they are discussed separately in the first two sections of the chapter. In the second section a set of approximate rules is included, the use of which should permit practitioners to make quick and reasonably accurate estimates of changes in power caused by altering certain lens parameters. The Cartesian sign convention2 is used throughout. For further understanding of the basic principles involved, readers are referred to the works of Bennett (1985), Tunnacliffe (1993), Freeman and Hull (2003), Douthwaite (2006) and Rabbetts (2007).
关键词： Lens Design,Astigmatism,Optics,Bifocal Contact Lenses,Power Variations,Contact Lenses,Ocular Refraction,Aberrations,Spectacles
更新于2025-09-23 15:23:52
-
Design and Optimization of a Solar Power Conversion System for Space Applications
摘要： This manuscript details a design method for a 500kW solar power based microgrid system for space applications. The design method utilizes multi-objective optimization with the Genetic Algorithm considering four parameters that characterize solar power based microgrids (battery voltage, PV maximum power, PV maximum power point voltage, and number of panels per string). The final optimization metric is the ratio of daily average deliverable power to total system mass (W/kg) metric. The microgrid system is composed of a number of modular DC-DC micro-converters, of which four topologies (buck, boost, buck-boost and non-inverting buck-boost) are evaluated and compared. The non-inverting buck-boost converter is determined to be the best candidate, and the optimal system characteristics are provided and analyzed. The final system design achieves a specific power of 35.56W/kg, with optimized result of 743.7V battery voltage, 439.5W PV maximum power, 182.7V PV maximum voltage, and three panels per string. Based on the optimizations results, a prototype is designed, tested, and analyzed in terms of efficiency and low temperature reliability. The converter achieved a peak efficiency of 98.4%, a power density of 3.54W/cm3, a specific power of 3.76W/g, and operated for over 267 hours of 11-minute low temperature cycles from 0oC to -140oC.
关键词： low temperature testing,photovoltaic systems,wide band gap semiconductors,maximum power point trackers,design optimization,non-inverting buck-boost,space exploration,system-level design,DC-DC power converters,microgrids
更新于2025-09-23 15:22:29
-
System Design for High-Capacity Unrepeatered Optical Transmission
摘要： By basing the figure of merit on the joint evaluation of signal BER and OSNR, the design of single-carrier 400G unrepeatered optical systems using remote optically-pumped amplifiers (ROPAs) with dedicated delivery fiber is discussed and analyzed in this work. Simulation results show very good agreement with experimental measurements, proving the effectiveness of the proposed approach in critical transmission situations.
关键词： remote optically-pumped amplifier (ROPA),distributed Raman amplifier (DRA),optical system design,Unrepeatered coherent transmission
更新于2025-09-23 15:22:29
-
Distance-Range-Oriented Constellation Design for VLC-SCMA Downlink with Signal-dependent Noise
摘要： In this paper, the constellation design for a sparse code multiple access (SCMA) based visible light communication (VLC) downlink is studied. The noise at the receiving avalanche photodiode (APD) is dependent on the signal intensity, and the associated design problems are typically intractable. We point out that for such a system both the minimum Euclidean distance (MED) and Rotated-MED based methods are not the optimal optimization objective, and propose a distance-range-oriented (DRO) modulation, where a linear combination of the minimum and maximum Euclidean distance is considered. We observe in the simulation results that the proposed DRO-based scheme outperform the MED and Rotated-MED based ones across a wide range of signal and noise levels.
关键词： distance range,signal-dependent noise,Constellation design,SCMA,visible light communication
更新于2025-09-23 15:22:29
-
Design status of the ITER core CXRS diagnostic setup
摘要： The Charge eXchange Recombination Spectroscopy diagnostic system on the ITER plasma core (CXRS core) will provide spatially resolved measurements of plasma parameters. The optical front-end is located in upper port 3 and the light of 460–665 nm is routed to spectrometers housed in the tritium building. This paper describes the layout of the optical system in the port plug, cell and interspace areas. The layout is a continuation of the developments described in [1] and takes into account changes in the design of the upper port plug, considerations for the system lifetime as well as internal and external tolerances on the optical chain. The layout was selected also with a number of additional criteria, including optical performance, radiation shielding, maintainability and robustness. A free-space optical chain was added pushing the optical fibres to the port cell. A line-of-sight finder imaging apertures and masks in the optical chain was added to enable determination of deviations within the optical chain and stabilise the image on the fibres. Where feasible, existing solutions for sub-systems such as the shutter were adapted to the layout.
关键词： Plasma diagnostic system,Diagnostic design,CXRS,Core Charge Exchange Recombination Spectroscopy,ITER
更新于2025-09-23 15:22:29
-
Siting and building-massing considerations for the urban integration of active solar energy systems
摘要： This paper aims to determine the optimum geometry of the building blocks in order to ensure the viable building integration of active solar energy systems in the urban fabric. Through literature review, similar research objectives are reported and analysed, whilst the building integration of active solar systems in urban areas is explored. The motivation for the proposed research emanates for a need for an analysis at the scale of urban blocks and of building massing configurations at the scale of a cluster of buildings rather than that of an individual building. These sets of physical characteristics are examined to arrive at simplified archetypes, while at the same time the habitation density is held constant. A set of twelve simplified building block configurations is created, whereby the geometrical parameters examined include the width of the streets separating the building blocks, the height of existing and proposed buildings and the massing configurations of the buildings that can be accommodated in the proposed building blocks. These parameters are manipulated to effect changes in collective building massing and siting decisions that result in the optimal integration of active solar energy systems that may be integrated on a building cluster's facades and roofs. Subsequently, the energy production potential of the buildings' integrated systems was calculated for each case so that the twelve simplified massing and siting configurations could be compared and contrasted, so as provide architectural designers as well as planning authorities a way of quantifying solar planning decisions at the neighbourhood scale.
关键词： Solar planning,Building integration,Sustainable development,Building massing,Urban design,Building insolation
更新于2025-09-23 15:22:29
-
[IEEE 2018 41st International Conference on Telecommunications and Signal Processing (TSP) - Athens, Greece (2018.7.4-2018.7.6)] 2018 41st International Conference on Telecommunications and Signal Processing (TSP) - Studying an Optimal Approach to Design Combined Fiber-Wireless Telecom Systems
摘要： We proposed a new approach to design interface hardware for next-generation telecom systems of combined fiber-wireless architecture based on nonlinear behavioral modeling in widespread off-the-shelf CAD tool NI AWRDE. To validate the approach, we research in detail a prospective base station operating in EU-assigned band (3.4-3.8 GHz) of 5G networks, which has easy-to-configure layout using the same cost- and power-efficient LW-VCSEL in downlink and uplink channels and direct modulation of LW-VCSEL in period-doubling state.
关键词： fronthaul fiber-wireless architecture,vertical cavity surface-emitting laser,base station,fifth-generation telecom network,computer-aided design
更新于2025-09-23 15:22:29
-
White light interferometry and MountainsMap? - case studies in static load capacity of bearings and surface finish optimisation of orthotic knee joints
摘要： This paper deals with two case studies demonstrating the combined use of white light interferometry and MountainsMap? software to: 1) accurately measure indentation diameters on race elements with an accuracy of a 1/100th of a micrometer and to examine static load capacity of bearings compared to the industry standard. In this case study, static load capacity of the ball bearings was shown to be 31% lower than that specified by ISO and ANSI/ABMA bearing standards; 2) characterise machined surfaces with 2D and 3D parameters, with the goal of producing optimal surface finish on orthotic knee joints used by Cerebral Palsy patients. In this case study, 2D roughness parameters Ra, Rq, Rp, Rz, and 3D roughness parameters Sa, Sq, Sp, Sz, were improved by 34%, 31%, 8%, 20%, and 36%, 33%, 6%, 6% respectively. Both case studies demonstrate the significance of modern topography techniques in enhancing the measurement accuracy of surface characteristics.
关键词： robust design,MountainsMap?,surface roughness,signal-to-noise (S/N) ratio,interferometry,WLI,static load capacity,white light,ball bearing indentations
更新于2025-09-23 15:22:29
-
A Design Principle for Actuation of Nematic Glass Sheets
摘要： A continuum mechanical framework is developed for determining (a) the class of stress-free deformed shapes and corresponding director distributions on the undeformed configuration of a nematic glass membrane that has a prescribed spontaneous stretch field and (b) the class of undeformed configurations and corresponding director distributions on it resulting in a stress-free given deformed shape of a nematic glass sheet with a prescribed spontaneous stretch field. The proposed solution rests on an understanding of how the Lagrangian dyad of a deformation of a membrane maps into the Eulerian dyad in three dimensional ambient space. Interesting connections between these practical questions of design and the mathematical theory of isometric embeddings of manifolds, deformations between two prescribed Riemannian manifolds, and the slip-line theory of plasticity are pointed out.
关键词： Thin sheets,Nematic glass,Actuation,Design
更新于2025-09-23 15:22:29
-
PEDOT:PSS temperature sensor ink-jet printed on paper substrate
摘要： In this work we present an ink-jet printed temperature sensor consisting of PEDOT:PSS printed on paper suitable for packaging, flexible electronics and other printed applications. The substrate showed to have a large influence on both the resistance as well as the temperature sensitivity of the PEDOT:PSS ink. This effect is most likely due to NaCl content in the photo paper coating, which reacts with the PEDOT:PSS. The temperature coefficient of a prepared device of α = ?0.030 relative to room temperature (22°C) was measured, which is higher than compared to for example Silicon α = ?0.075.
关键词： Manufacturing,Detector design and construction technologies and materials
更新于2025-09-23 15:22:29