| 1. |
- Andersson, Alf, et al.
(författare)
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Inline Process Control – a concept study of efficient in-line process control and process adjustment with respect to product geometry
- 2016
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Ingår i: Swedish Production Symposium 2016 SPS 2016. - Lund, Sweden.
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Konferensbidrag (refereegranskat)abstract
- All manufacturing processes have variation which may violate the fulfillment of assembly, functional, geometrical or esthetical requirements and difficulties to reach desired form in all areas. The cost for geometry defects rises downstream in the process chain. Therefore, it is vital to discover these defects as soon as they appear. Then adjustments can be done in the process without losing products or time. In order to find a solution for this, a project with the overall scope “development of an intelligent process control system” has been initiated. This project consists of five different work packages: Inline measurement, Process Evaluation, Corrective actions, Flexible tooling and demonstrator cell. These work packages address different areas which are necessary to fulfill the overall scope of the project. The system shall both be able to detect geometrical defects, propose adjustments and adjust simple process parameters. The results are demonstrated in a demo cell located at Chalmers University of Technology. In the demonstrator all the different areas have been verified in an industrial case study – assembly of GOR Volvo S80. Efficient offline programming for robot based measurement, efficient process evaluation based on case base reasoning (CBR) methodology, flexible fixtures and process adjustments based on corrective actions regarding in going part positioning.
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| 2. |
- Bauer, Andrej, et al.
(författare)
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The HoTT Library : A formalization of homotopy type theory in Coq
- 2017
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Ingår i: Proceedings of the 6th ACM SIGPLAN Conference on Certified Programs and Proofs. - New York, NY, USA : Association for Computing Machinery (ACM). - 9781450347051 ; , s. 164-172
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Konferensbidrag (refereegranskat)abstract
- We report on the development of the HoTT library, a formalization of homotopy type theory in the Coq proof assistant. It formalizes most of basic homotopy type theory, including univalence, higher inductive types, and significant amounts of synthetic homotopy theory, as well as category theory and modalities. The library has been used as a basis for several independent developments. We discuss the decisions that led to the design of the library, and we comment on the interaction of homotopy type theory with recently introduced features of Coq, such as universe polymorphism and private inductive types.
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| 3. |
- Bauer, Florian, 1975-, et al.
(författare)
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Evaluation of a Micro-Channel Plate PMT in PET
- 2006
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Ingår i: Nuclear Science Symposium Conference Record, 2006, IEEE. - 1424405602 ; , s. 2503-2505
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Konferensbidrag (refereegranskat)abstract
- The focus of this paper is the evaluation of micro-channel plate PMTs for PET detectors. Several properties of MCPs make them interesting for PET applications, such as fast time response, high spatial resolution, compact size, low susceptibility to magnetic fields, high gain and low power consumption. The preliminary tests in this paper are performed with the 51 mm times 51 mm square Burle 85011-501 assembly with 64 anodes (8 times 8). A new version of this MCP will be examined for the full paper. Initial measurements have been performed with a pulsed LASER (Hamamatsu Picosecond Light Pulser PLP-10 with M8903 Laser diode head). The engineering sample of the 85011 exhibited a time resolution of 26 ps. Further measurements will be performed, such as transit time measurements and timing measurements with scintillators. Single-photon timing measurements were presented earlier in [Ref. 1], from the old version as well as the suitability of the device in Cherenkov detectors in [Ref. 2]. For the full paper it is also planned to develop a circuit which allows lossless splitting of the anode signal.
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| 4. |
- Bauer, Maris, et al.
(författare)
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Terahertz detection with graphene field-effect transistors
- 2015
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Ingår i: Graphene Week 2015.
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Konferensbidrag (refereegranskat)abstract
- Detectors for quasi-optical and guide THz waves are key elements of any THz technology. In recent years, there has been much progress in their development. Notably, field-effect transistors (FETs) have been shown to be well suited for detector implementation at room temperature exploiting (self-)mixing effects in their channels [1]. They reach a typical noise-equivalent power (NEP) of several tens of pW/Hz^1/2 at 0.6 THz in CMOS and other technologies. First focal-plane arrays and cameras have been implemented. Frequency coverage to at least 5 THz has been demonstrated. Recently, this type of detection concept has been extended successfully to graphene-based FETs [2] opening the way to freely positionable THz detectors on a wide variety of substrates (also flexible plastics). We have improved the technology (see Fig. 1) [3] and reach, for GFETs on Si, an optical NEP of 150 pW/Hz^1/2 at 0.3 THz, with considerable room for improvement. An unusually strong thermoelectric contribution has been identified [2, 3] which may help to engineer enhanced detector performance.
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| 5. |
- Bauer, Maris, et al.
(författare)
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The potential for sensitivity enhancement by the thermoelectric effect in carbon-nanotube and graphene Tera-FETs
- 2015
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Ingår i: Journal of Physics: Conference Series. - : IOP Publishing. - 1742-6588 .- 1742-6596. ; 647:1, s. UNSP 012004-
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Konferensbidrag (refereegranskat)abstract
- We report on terahertz (THz) measurements with graphene field-effect transistors with integrated antennas (Tera-FETs) lay special emphasis on thermoelectric contributions to the detected THz photoresponse. Graphene Tera-FETs with integrated broad-band bow-tie antennas were fabricated in a CVD-based growth process and were successfully applied for detection at 600 GHz with optical NEPs down to 515 pW/Hz^1/2. While rectification of THz radiation by (distributed) resistive mixing of charge-density waves induced in the gated transistor channel region is well known, significant additional contributions to the detected signal have experimentally been observed and hot-carrier thermoelectric effects have been identified as a possible origin of these signals. We also observe similar signal contributions in carbonnanotube transistors.
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| 6. |
- Cibiraite, D., et al.
(författare)
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Thermal noise-limited sensitivity of FET-based terahertz detectors
- 2017
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Ingår i: 2017 International Conference on Noise and Fluctuations, ICNF 2017, Vilnius, Lithuania, 20-23 June 2017.
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Konferensbidrag (refereegranskat)abstract
- Here we present a detailed study on estimation of noise-dependent parameters, such as signal-to-noise ratio (SNR) or noise equivalent power (NEP), of field-effect-transistor based terahertz detectors (TeraFETs). Commonly, these parameters are estimated from a well-known assumption, that detector's performance is limited by the thermal noise of transistor's channel. However, practice shows that the influence of other noise sources or transient effects is considerable. We summarize TeraFET noise measurements performed on different material systems based transistors, such as AlGaN/GaN, AlGaAs/GaAs, silicon CMOS, and monolayer graphene. We have achieved a good agreement between thermal noise and measured data. However, attention has to be paid to gate leakage currents and slow defect charging and discharging effects, which can strongly influence TeraFET's performance estimation.
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| 7. |
- Zak, Audrey, 1990, et al.
(författare)
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20 μm gate width CVD graphene FETs for 0.6 THz detection
- 2014
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Ingår i: International Conference on Infrared, Millimeter, and Terahertz Waves, IRMMW-THz. - 2162-2027 .- 2162-2035. ; , s. Art. no. 6956250-
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Konferensbidrag (refereegranskat)abstract
- We have fabricated 20 μm gate width graphene field effect transistors (GFETs) based on graphene grown by chemical vapor deposition (CVD). These GFETs are integrated with split bow-tie antennae for room temperature, direct detection of a 0.6 THz signal. Our detectors reach a maximum optical responsivity of 3.0 V/W and a minimum noise-equivalent power (NEP) of 700 pW/Hz^0.5. The successful demonstration of THz detection using CVD graphene introduces the possibility for scalable detector production.
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