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IEEE Open Journal of Circuits and systems 2025年

作者： Scherzer, Maximilian Auer, Mario Graz University of Technology Institute of Electrical Measurement and Sensor Systems Austria

In this article an integrated fully differential current amplifier is presented. It was designed for inductive sensor excitation, in this case for a fluxgate sensor, however the concept is applicable wherever a low noise and precise current is required. A brief review of some of the basic elements of the circuit is given, followed by the development of a model that takes into account output impedance limitations due to mismatch and stability criteria, an essential consideration in the design of a stable current amplifier for inductive loads. Based on the proposed model, the design and implementation of the current amplifier is outlined, identifying potential difficulties for on-chip integration. The final design was then fabricated using a standard 180 nm CMOS technology. measurement results show that the circuit draws only 2.8 mA from a 3.3 V supply voltage and occupies a total area of 0.64 mm2. Special efforts were made to accurately evaluate the output impedance, whereby a value of 436 kΩ was recorded. In addition, the current amplifier achieves an output-referred noise current of 2.5 nA/Hz, resulting in a measured signal-to-noise ratio of more than 105.2 dB for a bandwidth of 512 Hz at an output current of 9 mAp-p. © 2025 IEEE.

关键词： Differential amplifiers

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Phase manipulating Fresnel lenses for wide-field quantitative phase imaging

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Optics Letters 2025年第8期50卷 2683-2686页

作者： Wang, Shengjia Dong, Bo Xiong, Jianxuan Liu, Lei Shan, Mingguang Koch, Alexander W. Gao, Shuai Key Laboratory of Photonic Materials and Device Physics for Oceanic Applications Ministry of Industry and Information Technology Harbin Engineering University Harbin150001 China Department of Physics Politecnico di Milano Piazza Leonardo Da Vinci 32 Milano20133 Italy College of Information and Communication Engineering Harbin Engineering University Harbin150001 China Institute for Measurement Systems and Sensor Technology Technical University of Munich Arcisstr. 21 Munich80333 Germany

For well-magnified imaging systems that satisfy the Nyquist criterion, camera pixels resolve the fine details provided by the objective lens. However, the mismatch in a space-bandwidth product (SBP) between the objective lenses and digital cameras leads to major sacrifices in the optical field of view (FOV). This Letter presents a framework of phase manipulating Fresnel lenses (PMFL) to bridge this SBP gap in quantitative phase imaging (QPI) modality. This framework breaks through the conventional design paradigm of interferometric QPI, converting it from the combination of individual optical elements to a direct phase transform of the optical field. The wide-field QPI is implemented by a single dynamic PMFL mask, which conducts differential interference and scans the opticalFOVacross the camera sensor. We built a microscopic platform equipped with the PMFL module to image both natural and artificial samples and expanded the FOV for a given camera by factors of 3×3, 2×2, and 4×1, respectively. © 2025 Optica Publishing Group.

关键词： Digital cameras

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Refractive index characterization and modeling of polymerization-dependent refractive index variations in two-photon polymerization resins

Optics Continuum

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Optics Continuum 2025年第5期4卷 996-1005页

作者： Golf Feigl Daniel Zaugg Jakob W Hinum-Wagner Samuel M Hörmann Alexer Bergmann Graz University of Technology Institute of Electrical Measurement and Sensor Systems Inffeldgasse 33 8010 Graz Austria Christian Doppler Laboratory for Structured Matter Based Sensing 8010 Graz Austria ams OSRAM Group Tobelbader Strasse 30 8141 Premstaetten Austria

Two-photon polymerization (2PP) is a cutting-edge technique for fabricating precise micro- and nanostructures, with applications in photonics, biomedical engineering, and micro-optics. A critical factor influencing the optical performance of 2PP-fabricated structures is the refractive index (RI) of the printed parts. This study analyzes the refractive indices of three resins developed by UpNano GmbH . Using a Pulfrich refractometer, dispersion curves of the polymerized resins were measured across the visible to near-infrared spectrum (450 nm – 1550 nm), and temperature-dependent RI behavior was characterized for both liquid and polymerized resins (15°C – 50°C). The RI of the polymerized resins ranges from 1.496 to 1.567. What we believe to be a novel model was developed to account for periodic RI fluctuations inherent in 2PP-printed parts due to voxel-based polymerization patterns. The model fits experimental data well and provides additional insights into the degree of polymerization within printed samples. These findings not only enhance understanding of the optical properties of 2PP-fabricated structures but also suggest opportunities for tailoring materials for gradient-index optics and other advanced optical applications.

关键词： Femtosecond lasers Gradient index optics Optical components Optical properties Refractive index Ultrafast lasers

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Portable Electronic Devices in Cabin and Cockpit – Analysis of Hazards

Portable Electronic Devices in Cabin and Cockpit – Analysis...

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AIAA Science and technology Forum and Exposition, AIAA SciTech Forum 2025

作者： Holz, Simon Pfaff, Jonas Kuder, Jürgen Schopferer, Sebastian May, Michael Norrefeldt, Victor Pathak, Arnav Pschirer, Marie Kienberger, Maximilian Fraunhofer Institute for High-Speed Dynamics Ernst-Mach-Institut Research Group Computational Physics EMI Dpt. Materials and Simulation Methods Freiburg79104 Germany Fraunhofer Institute for High-Speed Dynamics Dpt. Measurement and Sensor Technology Ernst-Mach-Institut EMI Freiburg79104 Germany Fraunhofer Institute for High-Speed Dynamics Department Resilience Safety and Security Ernst-Mach-Institut EMI Freiburg79104 Germany Fraunhofer Institute for Building Physics IBP Research Group Vehicle Climate Control Systems Dpt. Indoor Climate Valley83626 Germany Fraunhofer Institute for Building Physics IBP Valley83626 Germany

ISBN: (数字)9781624107238

ISBN: (纸本)9781624107238

Multiple portable electronic devices (PED) such as smartphones and laptops are carried during flight in cabin and cockpit by passenger and crew. When the Lithium-Ion batteries of PEDs go into thermal runaway flammable and toxic gases are released. In the first part of this study a total of 26 laptops, tablets, smartphones, and power tool batteries have been forced into thermal runaway in a ventilated test box (V=350 l, V=13 l/s) observing smoke and fire as the main hazards. Correlations of the venting volume depending on the energy content of the PED are presented. The volume released during fire hazard is seven times the volume released during smoke hazard. Up to 3 l of electrolyte and up to 0.4 l hydrogen fluoride, hydrogen chloride and formaldehyde as well as up 20 l of combustion products of plastics are released during the full test time. For tablets and smartphones, the smoldering of plastics prior to the thermal runaway could be noted visually and due to a rise in propane emissions. In the second part of this study thermal runaway tests with laptops in a A320 mockup (V=13 m³) under realistic ventilation (V=60 l/s) are presented. The nine tested laptops were used to generate thermal runaway events on the floor, on seats and in the overhead bin. The increase of air temperature in the cabin depends on the distance from the floor, and may be as high as 60 K. The CO2 concentration level in the cabin increases and it takes 16 to 26 min to restore 105 % of the level measured prior to thermal runaway. Finally, the absolute amounts of vent gases are presented and clustered for e.g. toxic and flammable gases or evaporated electrolyte. The presented data will enable the prediction of local concentrations inside occupied areas of the cabin during thermal runaway by CFD simulations. © 2025, American institute of Aeronautics and Astronautics Inc, AIAA. All rights reserved.

关键词： Fire hazards

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Fiber optic sensor network for lightning impact localization and classification in wind turbines

Fiber optic sensor network for lightning impact localization...

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2006 IEEE International Conference on Multisensor Fusion and Integration for Intelligent systems, MFI

作者： Krämer, Sebastian G. M. León, Fernando Puente Appert, Benoît Institute for Measurement Systems and Sensor Technology Distributed Measurement Systems Area Technical University of Munich 80290 Munich Germany

ISBN: (纸本)1424405661

As wind turbines are increasing both in number and in height, they are exposed to a major threat in form of lightning strikes. The protection of these structures from the effects of lightning is an important issue in today's wind turbine development. However, as lightning is random in nature, a complete protection against its damages is not achievable. The presented method for lightning impact localization and classification using a fiber optic current sensor network helps to detect damages caused by lightning and to monitor the blades. The system is connected to the wind turbine control and monitoring system. © 2006 IEEE.

关键词： Wind turbines

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Design of a Thermal Battery Dummy with Integrated sensor Node 32

Design of a Thermal Battery Dummy with Integrated Sensor Nod...

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32nd IEEE International Symposium on Industrial Electronics, ISIE 2023

作者： Grubmuller, Michael Schweighofer, Bernhard Wegleiter, Hannes Graz University of Technology Institute of Electrical Measurement and Sensor Systems Graz Austria

ISBN: (纸本)9798350399714

High-performance Li-ion battery systems require sophisticated thermal management to ensure safe operation and long battery life. Testing such thermal management systems comes with some disadvantages and safety concerns. For this reason, the use of thermal battery dummies is advantageous. In this work, we present the design of a thermal battery dummy with 26650 cylindrical cell geometry with an integrated sensor node. The control of the heating power and the temperature measurement is done inside the dummy cell. Power supply and communication with a test bench computer are done through the supply lines. Thus, the only cell connections are the battery terminals, resulting in a dummy cell with geometric characteristics equivalent to a real Li-ion cylindrical cell. This and an addressing-based communication protocol allows parallel operation of multiple battery dummies in a dummy pack compound. The design of the thermal parameters is based on preceding thermal measurements on a real battery cell;in the following we explain the concept of the thermal dummy and go into more detail on the main electronic circuits. With final measurements on a prototype we show the achieved properties of the thermal dummy. © 2023 IEEE.

关键词： sensor nodes

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Fiber-optic current sensors for lightning detection in wind turbines

Fiber-optic current sensors for lightning detection in wind ...

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Optical Fiber sensors, OFS 2006

作者： Krämer, Sebastian G.M. León, Fernando Puente Institute for Measurement Systems and Sensor Technology Technical University Munich 80290 Munich Germany

ISBN: (纸本)1557528179

Fiber optic sensors are immune against electromagnetic interference (EMI). Hence a fiber optic current sensor network can be used for lightning detection and classification in insulating materials. The first application includes the monitoring of big structures made of composite materials like wind turbine blades. © 2006 OSA/OFS 2006.

关键词： Wind turbine blades

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Configuration of a sparse network of LIDAR sensors to identify security-relevant behavior of people

Configuration of a sparse network of LIDAR sensors to identi...

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Unmanned/Unattended sensors and sensor Networks VI Conference

作者： Wenzl, Konrad Ruser, Heinrich Kargel, Christian Bundeswehr University Munich Institute for Measurement and Automation Division of Sensor Technology and Measurement Systems 85577 Neubiberg/Munich Germany

ISBN: (纸本)9780819477866

Surveillance is an important application of sensor networks. In this paper it is demonstrated how a sparse network of stationary infrared (IR) sensors with highly directional, stationary beam patterns based on the LIDAR principle can be used to reliably track persons. Due to the small number of sensors and their narrow beam patterns a significant portion of the area to be surveilled is not directly assessed by the sensors. To nonetheless achieve reliable tracking of moving targets in the entire area to be monitored, we employ the most appropriate sensor network configuration and propose a probabilistic tracking approach. The behavior of a person moving through the area of observation is classified as "normal" or "abnormal" depending upon the trajectory and motion dynamics. The classification is based on a linear Kalman prediction. © 2009 Copyright SPIE - The International Society for Optical Engineering.

关键词： Optical radar

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Detection and tracking of humans with a sparse network of LIDAR sensors

Detection and tracking of humans with a sparse network of LI...

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Intelligent Sensing, Situation Management, Impact Assessment, and Cyber-Sensing

作者： Ruser, Heinrich Wenzl, Konrad Kargel, Christian Bundeswehr University Munich Institute for Measurement and Automation Division of Sensor Technology and Measurement Systems 85577 Neubiberg/Munich Germany

ISBN: (纸本)9780819476180

The applicability of a sparse sensor network with only two sensor nodes and a small number of directional LIDAR sensors to detect and track humans in an area of surveillance is investigated. The detection and tracking performances are evaluated for various positions of the two nodes as a function of the number of sensors per node and the sensor beamwidths. A quality factor incorporating the area coverage ratio and the position error is introduced to find the best network configuration with a minimal number of sensors yielding a position accuracy sufficient for the task at hand. Extensive simulations and measurements with two laserscanners to emulate the LIDAR sensors were carried out for straight trajectories uniformly distributed over the area of surveillance. In order to improve the tracking performance, we used a Kalman filter based approach. As in our application a spatial mean RMS position error of approx. 0.6 m is sufficient, each of the two sensor nodes must be equipped with 4 LIDAR sensors with a -3dB-beamwidth of 12. ©2009 SPIE.

关键词： Optical radar

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Ageing of roughness artefacts - Impact on the measurement results 17

Ageing of roughness artefacts - Impact on the measurement re...

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17th International Conference of the European Society for Precision Engineering and Nanotechnology, EUSPEN 2017

作者： Klauer, Katja Eifler, Matthias Schneider, Frank Seewig, Jörg Aurich, Jan C. University of Kaiserslautern Institute for Measurement and Sensor-Technology Germany University of Kaiserslautern Institute for Manufacturing Technology and Production Systems Germany

ISBN: (纸本)9780995775107

Ageing effects can influence the properties of engineering surfaces, especially when highly precise surface structures like roughness artefacts are considered. In order to describe the behaviour of roughness artefacts after a given period of use and storage, the impact of ageing on their use and recommendations for their handling are investigated. In the experimental studies the roughness artefacts were exposed to constant temperatures in a climatic chamber and extracted after individually defined time spans before their surface topography was characterised with a large number of stylus instrument measurements. As a quality indicator the ISO 13565-2 roughness parameters were evaluated to characterise the ageing process at different temperatures.

关键词： Surface roughness

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