Control of fast electron propagation in foam target by high-Z doping

The influence of high-Z dopant (Bromine) in low-Z foam (polystyrene) target on laser-driven fast electron propagation is studied by the 3D hybrid particle-in-cell (PIC)/fluid code HEETS.It is found that the fast electrons are better confined in doped targets due to the increasing resistivity of the target, which induces a stronger resistive magnetic field which acts to collimate the fast electron propagation.The energy deposition of fast electrons into the background target is increased slightly in the doped target, which is beneficial for applications requiring long distance propagation of fast electrons, such as fast ignition

Double-layer Perfect Metamaterial Absorber and Its Application for RCS Reduction of Antenna

To reduce the radar cross section (RCS) of a circularly polarized (CP) tilted beam antenna, a double-layer perfect metamaterial absorber (DLPMA) in the microwave frequency is proposed. The DLPMA exhibits a wider band by reducing the distance between the three absorption peaks. Absorbing characteristics are analyzed and the experimental results demonstrate that the proposed absorber works well from 5.95 GHz to 6.86 GHz (relative bandwidth 14.1%) with the thickness of 0.5 mm. Then, the main part of perfect electric conductor ground plane of the CP tilted beam antenna is covered by the DLPMA. Simu¬lated and experimental results reveal that the novel antenna performs well from 5.5 GHz to 7 GHz, and its monostatic RCS is reduced significantly from 5.8 GHz to 7 GHz. The agreement between measured and simulated data validates the present design

Optical properties of 4 A single-walled carbon nanotubes inside the zeolite channels studied from first principles calculations

The structural, electronic, and optical properties of 4 A single-walled carbon nanotubes (SWNTs) contained inside the zeolite channels have been studied based upon the density-functional theory in the local-density approximation (LDA). Our calculated results indicate that the relaxed geometrical structures for the smallest SWNTs in the zeolite channels are much different from those of the ideal isolated SWNTs, producing a great effect on their physical properties. It is found that all three kinds of 4 A SWNTs can possibly exist inside the Zeolite channels. Especially, as an example, we have also studied the coupling effect between the ALPO_4-5 zeolite and the tube (5,0) inside it, and found that the zeolite has real effects on the electronic structure and optical properties of the inside (5,0) tube.Comment: 9 pages, 6figure