arXiv subjects

W. Sun

Publications and source records attributed to W. Sun.

22 records · Page 2Linked to original sources

arXiv2011

Discovery of a Be/X-ray pulsar binary and associated supernova remnant in the Wing of the SMC

We report on a new Be/X-ray pulsar binary located in the Wing of the Small Magellanic Cloud (SMC). The strong pulsed X-ray source was discovered with the Chandra and XMM-Newton X-ray observatories. The X-ray pulse period of 1062 s is consistently determined from both Chandra and XMM-Newton observations, revealing one of the slowest rotating X-ray pulsars known in the SMC. The optical counterpart of the X-ray source is the emission-line star 2dFS 3831. Its B0-0.5(III)e+ spectral type is determined from VLT-FLAMES and 2dF optical spectroscopy, establishing the system as a Be/X-ray binary (Be-XRB). The hard X-ray spectrum is well fitted by a power-law with additional thermal and blackbody components, the latter reminiscent of persistent Be-XRBs. This system is the first evidence of a recent supernova in the low density surroundings of NGC 602. We detect a shell nebula around 2dFS 3831 in H-alpha and [O III] images and conclude that it is most likely a supernova remnant. If it is linked to the supernova explosion that created this new X-ray pulsar, its kinematic age of (2-4)x10^4 yr provides a constraint on the age of the pulsar.

astro-ph.SR↗

arXiv2008

In-Plane Bistable Nanowire For Memory Devices

We present a nanomechanical device design to be used in a non-volatile mechanical memory point. The structure is composed of a suspended slender nanowire (width : 100nm, thickness 430nm length : 8 to 30$μ$m) clamped at its both ends. Electrodes are placed on each sides of the nanowire and are used to actuate the structure (writing, erasing) and to measure the position through a capactive bridge (reading). The structure is patterned by electron beam lithography on a pre-stressed thermally grown silicon dioxide layer. When later released, the stressed material relaxes and the beam buckles in a position of lower energy. Such symmetric beams, called Euler beams, show two stable deformed positions thus form a bistable structure. This paper will present the fabrication, simulation and mechanical and electrical actuation of an in plane bistable nanowire. Final paper will include a section on FEM simulations.

cs.OH↗

arXiv1996

Onsager Relations and Hydrodynamic Balance Equations in 2D Quantum Wells

In this letter we clarify the role of heat flux in the hydrodynamic balance equations in 2D quantum wells, facilitating the formulation of an Onsager relation within the framework of this theory. We find that the Onsager relation is satisfied within the framework of the 2D hydrodynamic balance equation transport theory at sufficiently high density. The condition of high density is consonant with the requirement of strong electron-electron interactions for the validity of our balance equation formulation.

cond-mat↗

arXiv1996

Tests of a High Resolution Time of Flight System Based on Long and Narrow Scintillator

We have tested a prototype time-of-flight system based on bulk scintillator block of dimensions $2.5 \times 2.5 \times 200$ cm. Using a calibration scheme similar to the one used in actual collider experiments, we have achieved a resolution of 71 ps using Amperex XP2020/UR photomultipliers and 81 ps using proximity-focusing fine-mesh photomultipliers (Hamamatsu R2021). Results are also obtained for scintillating fiber blocks of the same dimensions. Good internal reflectivity of the bulk scintillator block resulted in resolutions superior to the fibre blocks. A single-photon pulsed laser system was used to study photomultipliers and the results were used in a Monte Carlo simulation of the system to study the critical elements that determine the resolution.

hep-ex↗