We present two ROSAT PSPC observations of the radio-loud, lobe-dominated quasar 3C 351, which shows an ‘ionized absorber’ in its X-ray spectrum. The factor 1.7 change in flux in the ∼2 years between the observations allows a test of models for this ionized absorber. The absorption feature at ∼ 0.7 keV (quasar frame) is present in both spectra but with a lower optical depth when the source inten...

Direct impedance control (DIC) technique used for an electroacoustic absorber in this paper requires a pair of pressure and velocity sensor. However, it can be quite costly to develop array system of this electrostatic absorber for acoustically large space. To overcome this problem, in this paper instead of using velocity sensor, disturbance-observer-type velocity estimator is applied to DIC te...

In this work, we have designed, fabricated and experimentally characterized a printed graphene nano-flakes enabled flexible and conformable wideband radar absorber. The absorber covers both X (8-12 GHz) and Ku (12-18 GHz) bands and is printed on flexible substrate using graphene nano-flakes conductive ink through stencil printing method. The measured results show that an effective absorption (a...

In this paper, two-section mode-locked lasers consisting of monolithic quantum dot gain and absorber sections are studied as a function of absorber voltage, injected current to the gain region, and relative section lengths. We map the regions of stable mode-locking as measured by the electrical and optical spectra. A simple algorithm is presented that evaluates the quality of mode locking and a...

A novel microwave metamaterial absorber design is introduced along with its manufacturing and characterization. Significant results considering both bandwidth and angular stability are achieved. Parametric analysis and simplified equivalent circuit are provided to give an insight on the key elements influencing the absorber performance. In addition, the constitutive parameters of the effective ...

The polarization-sensitive cross slot antenna recently constructed by Papathanakos [1] was used to investigate the possibility of designing a polarization-sensitive bolometric detector. A bolometer or other absorber located near a polarizationsensitive antenna may couple to the antenna, preferentially absorbing electromagnetic waves of the polarization radiated by the antenna. Lock-in amplifica...

In this paper, the method of determining thermal contact resistance of wavy surfaces is discussed exactly. For determining the thermal contact resistance of real contacts, a new method has been presented. In this method, assuming a regular sinusoidal surface profile, the real contact area in terms of applied forces has been determined. Then thermal contact resistance has been calculated. Testin...

Concentrating collectors are also known as focusing collectors. A parabolic trough is a type of concentrating collector in which the energy from the sunlight is reflected and focused on the absorber tube. This paper focused on the performance of parabolic trough collector which has a ceramic-Metal coating on the absorber tube. A comparison of performance has made between with and without coatin...

The influence of recycling on double-pass solar air collectors with welding of the V-corrugated absorber has been studied experimentally and theoretically. Welding the V-corrugated absorber and the recycle-effect concept to the solar air collector was proposed to strengthen the convective heat-transfer coefficient due to turbulence promotion. Both the recycle effect and the V-corrugated absorbe...