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University of Twente Publications (48,515 recursos)
University of Twente Repository provides publications of UT scientific staff, in many cases full text and publicly available.

Type = Article

Mostrando recursos 1 - 20 de 22,184

1. On-chip microwave photonic beamformer circuits operating with phase modulation and direct detection - Zhuang, L.; Hoekman, M.; Taddei, C.; Leinse, A.; Heideman, R.G.; Hulzinga, A.; Verpoorte, J.; Oldenbeuving, R.M.; Dijk, P.W.L. van; Boller, K.J.; Roeloffzen, C.G.H.
We propose and experimentally demonstrate the working principles of two novel microwave photonic (MWP) beamformer circuits operating with phase modulation (PM) and direct detection (DD). The proposed circuits incorporate two major signal processing functionalities, namely a broadband beamforming network employing ring resonator-based delay lines and an optical sideband manipulator that renders the circuit outputs equivalent to those of intensity-modulated MWP beamformers. These functionalities allow the system to employ low-circuit-complexity modulators and detectors, which brings significant benefits on the system construction cost and operation stability. The functionalities of the proposed MWP beamformer circuits were verified in experimental demonstrations performed on two...

2. Nanosheet controlled epitaxial growth of PbZr0.52Ti0.48O3 thin films on glass substrates - Bayraktar, M.; Chopra, A.; Bijkerk, F.; Rijnders, G.
Integration of PbZr0.52Ti0.48O3 (PZT) films on glass substrates is of high importance for device applications. However, to make use of the superior ferro- and piezoelectric properties of PZT, well-oriented crystalline or epitaxial growth with control of the crystal orientation is a prerequisite. In this article, we report on epitaxial growth of PZT films with (100)- and (110)-orientation achieved by utilizing Ca2Nb3O10 (CNO) and Ti0.87O2 (TO) nanosheets as crystalline buffer layers. Fatigue measurements demonstrated stable ferroelectric properties of these films up to 5 × 109 cycles. (100)-oriented PZT films on CNO nanosheets show a large remnant polarization of 21 μC/cm2 that is the highest...

3. De taakinhoud, de taakomvang en de taakbelasting van schoolleiders in het basisonderwijs - Stoel, W.G.R.

4. Inleiding: Nuances in autonomie - Scheerens, J.

5. Het ontwerpen van tests met verschillende optimaliteitscriteria - Berger, Martijn P.F.; Linden, Wim J. van der

6. Classroom composition and individual achievement : effects of classroom composition and teacher goals in Dutch elementary education - Luyten, Hans; Hoeven-van Doornum, Anneke

7. De opbrengsten van het basisonderwijs: een repliek - Linden, W.J. van der; Zwarts, M.A.

8. Robustness of judgments in evaluation research - Linden, W.J. van der; Zwarts, M.A.

9. School- en sekseverschillen in vakkenkeuzen in het VWO - Bosker, Roel J.; Dekkers, H.P.J.M.

10. School effects on drop out : a multi-level logistic approach to assessing school-level correlates of drop out of ethnic minorities - Bosker, Roel; Hofman, W.H. Adriaan

11. The school-level context of instructional effectiveness: a comparison between school effectiveness and restructuring models - Scheerens, Jaap

12. Coördinatie en de effectiviteit van het onderwijs op het vakgebied wiskunde - Witziers, B.

13. The effects of teachers' attitudes and practices on the achievements of dutch low SES pupils - Velden, Lud van der

14. Training voor transfer van statistische vaardigheden : toepassing van een vier-componenten instructie-ontwerpmodel - Paas, Fred G.W.C.; Merriënboer, Jeroen J.G. van

15. Onderwijskundig leiderschap en leerlingprestaties in het basisonderwijs - Grift, W. van de; Akkermans, W.

16. Leren en transfer : het gebruik van een leerkiem - Vos, H.

17. De contextgebondenheid van effectiviteitsbevorderende schoolkenmerken - Brandsma, Hennie; Knuver, Anja

18. De consistentie van schooleffecten in het basisonderwijs - Bosker, Roel J.

19. Onderwijseffectiviteit : overwegingen voor een programma van onderzoek - Creemers, Bert P.M.; Scheerens, Jaap

20. Development and validation of a patient-tailored dose regime in myocardial perfusion imaging using czt-spect - Dijk, J.D. van; Jager, P.L.; Mouden, M.; Slump, C.H.; Ottervanger, J.P.; Boer, J. de; Oostdijk, A.H.J.; Dalen, J.A. van
Background: Guidelines for SPECT myocardial perfusion imaging (MPI) traditionally recommend a fixed tracer dose. Yet, clinical practice shows degraded image quality in heavier patients. The aim was to optimize and validate the tracer dose and scan time to obtain a constant image quality less dependent on patients’ physical characteristics. Methods: 125 patients underwent Cadmium Zinc Telluride (CZT)-SPECT stress MPI using a fixed Tc-99m-tetrofosmin tracer dose. Image quality was scored by three physicians on a 4-point grading scale and related to the number of photon counts normalized to tracer dose and scan time. Counts were correlated with various patient-specific parameters dealing with...

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