Conformal phased array with beam forming for airborne satellite communication

For enhanced communication on board of aircraft novel antenna systems with broadband satellite-based capabilities are required. The installation of such systems on board of aircraft requires the development of a very low-profile aircraft antenna, which can point to satellites anywhere in the upper hemisphere. To this end, phased array antennas which are conformal to the aircraft fuselage are attractive. In this paper two key aspects of conformal phased array antenna arrays are addressed: the development of a broadband Ku-band antenna and the beam synthesis for conformal array antennas. The antenna elements of the conformal array are stacked patch antennas with dual linear polarization which have sufficient bandwidth. For beam forming synthesis a method based on a truncated Singular Value Decomposition is proposed

Technical challenges for FLASH proton therapy

There is growing interest in the radiotherapy community in the application of FLASH radiotherapy, wherein the dose is delivered to the entire treatment volume in less than a second. Early pre-clinical evidence suggests that these extremely high dose rates provide significant sparing of healthy tissue compared to conventional radiotherapy without reducing the damage to cancerous cells. This interest has been reflected in the proton therapy community, with early tests indicating that the FLASH effect is also present with high dose rate proton irradiation. In order to deliver clinically relevant doses at FLASH dose rates significant technical hurdles must be overcome in the accelerator technology before FLASH proton therapy can be realised. Of these challenges, increasing the average current from the present clinical range of 1–10 nA to in excess of 100 nA is at least feasible with existing technology, while the necessity for rapid energy adjustment on the order of a few milliseconds is much more challenging, particularly for synchrotron-based systems. However, the greatest challenge is to implement full pencil beam scanning, where scanning speeds 2 orders of magnitude faster than the existing state-of-the-art will be necessary, along with similar improvements in the speed and accuracy of associated dosimetry. Hybrid systems utilising 3D-printed patient specific range modulators present the most likely route to clinical delivery. However, to correctly adapt and develop existing technology to meet the challenges of FLASH, more pre-clinical studies are needed to properly establish the beam parameters that are necessary to produce the FLASH effect

Large interfacial spin-orbit torques in layered antiferromagnetic insulator NiPS3/ferromagnet bilayers

Finding efficient ways of manipulating magnetic bits is one of the core goals in spintronic research. Electrically-generated spin-orbit torques (SOTs) are good candidates for this and the search for materials capable of generating highly-efficient SOTs has gained a lot of traction in the recent years. While antiferromagnet/ferromagnet bilayer structures have been employed extensively for passive applications, e.g. by using exchange bias fields, their active properties are not yet widely employed. Here we show the presence of large interfacial SOTs in bilayer of a ferromagnet and the two-dimensional layered antiferromagnetic insulator NiPS$_3$. We observe a large in-plane damping-like interfacial torque, showing a torque conductivity of $\sigma_\mathrm{DL} \approx 1 \times 10^{5} \mathrm{(\frac{\hbar}{2e}) /(\Omega m)}$ even at room temperature, comparable to the best devices reported in the literature for standard heavy-metal-based and topological insulators-based devices. Additionally, our devices also show an out-of-plane field-like torque arising from the NiPS$_3$/ferromagnet interface, further indicating the presence of an interfacial spin-orbit coupling in our structures. Temperature-dependent measurements reveal an increase of the SOTs with a decreasing temperature below the N\'eel temperature of NiPS$_3$ ($T_N \approx 170 \mathrm{K}$), pointing to a possible effect of the magnetic ordering on our measured SOTs. Our findings show the potential of antiferromagnetic insulators and two-dimensional materials for future spintronic applications.Comment: 19 pages, 3 figures, 1 table. Changed units of the torque normalized by the electric field from $\mathrm{\mu m \, T/V}$ to $\mathrm{nm \, T/V}

Bijzondere apparatuur op de Waiboerhoeve

In dit artikel wordt een deel van de speciale machines die op de Waiboerhoeve in gebruik zijn kort beschreven: - een voermengwagen voor vleeskalveren; - een graszaaimachine voor het goed aanleggen van verschillende grasrassen; - een monsterapparaat voor het nemen van grondmonsters; - een kunstmeststrooier; - een grasoogstmachin

Wat is er komend jaar te zien op de Waiboerhoeve

Per jaar wordt op de Waiboerhoeve aan ongeveer 90 proeven aandacht besteed. Deze proeven zijn op te delen in twee soorten, het systeemonderzoek en het detailonderzoek