Jingqiang Li

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We present high-resolution X-ray spectra of the multiple (hierarchical quadruple) weak-lined T Tauri star system HD 98800, obtained with the High Energy Transmission Gratings Spectrograph (HETGS) aboard the Chandra X-ray Observatory (CXO). In the zeroth-order CXO/HETGS X-ray image, both principle binary components of HD 98800 (A and B, separation 0.8) are(More)
We report the discovery, by the Chandra X-Ray Observatory, of X-ray emission from the bipolar planetary nebula Menzel 3. In Chandra CCD imaging, Mz 3 displays hot [∼ K] gas within its twin, coaxial 6 (3–6) # 10 bubbles of optical nebulosity as well as a compact X-ray source at the position of its central star(s). The brightest diffuse X-ray emission lies(More)
We report the discovery, by the Chandra X-ray Observatory, of X-ray emission from the bipolar planetary nebula Menzel 3. In Chandra CCD imaging, Mz 3 displays hot (∼ 3 − 6 × 10 K) gas within its twin, coaxial bubbles of optical nebulosity, as well as a compact X-ray source at the position of its central star(s). The brightest diffuse X-ray emission lies(More)
Chandra X-Ray Observatory (CXO) images have revealed that the X-ray–emitting regions of the moleculerich young planetary nebulae (PNe) BD +30 3639 and NGC 7027 are much more asymmetric than their optical nebulosities. To evaluate the potential origins of these X-ray asymmetries, we analyze X-ray images of BD +30 3639, NGC 7027, and another PN resolved by(More)
We present polarimetric imaging of the protoplanetary nebula RAFGL 2688 obtained at 4.5 μm with the Infrared Space Observatory (ISO). We have deconvolved the images to remove the signature of the point spread function of the ISO telescope, to the extent possible. The deconvolved 4.5 μm image and polarimetric map reveal a bright point source with faint,(More)
Subpixel event repositioning (SER) techniques have been demonstrated to significantly improve the already unprecedented spatial resolution of Chandra X-ray imaging with the Advanced CCD Imaging Spectrometer (ACIS). Chandra CCD SER techniques are based on the premise that the impact position of events can be refined, based on the distribution of charge among(More)
In this paper, a new method for the separate extraction of the temperature-dependent source (<inline-formula> <tex-math notation="LaTeX">$R_{s}$ </tex-math></inline-formula>) and drain (<inline-formula> <tex-math notation="LaTeX">$R_{d}$ </tex-math></inline-formula>) access resistances in gallium nitride (GaN) high electron-mobility transistors (HEMTs) by(More)
We further investigate subpixel event repositioning (SER) algorithms in application to Chandra X-ray Observatory (CXO) CCD imaging. SER algorithms have been applied to backside illuminated (BI) Advanced CCD Imaging Spectrometer (ACIS) devices, and demonstrate spatial resolution improvements in Chandra/ACIS observations. Here a new SER algorithm that is(More)
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