649 research outputs found
An hourglass model for the flare of HST-1 in M87
To explain the multi-wavelength light curves (from radio to X-ray) of HST-1
in the M87 jet, we propose an hourglass model that is a modified two-zone
system of Tavecchio & Ghisellini (hereafter TG08): a slow hourglass-shaped or
Laval nozzle-shaped layer connected by two revolving exponential surfaces
surrounding a fast spine, through which plasma blobs flow. Based on the
conservation of magnetic flux, the magnetic field changes along the axis of the
hourglass. We adopt the result of TG08---the high-energy emission from GeV to
TeV can be produced through inverse Compton by the two-zone system, and the
photons from radio to X-ray are mainly radiated by the fast inner zone system.
Here, we only discuss the light curves of the fast inner blob from radio to
X-ray. When a compressible blob travels down the axis of the first bulb in the
hourglass, because of magnetic flux conservation, its cross section experiences
an adiabatic compression process, which results in particle acceleration and
the brightening of HST-1. When the blob moves into the second bulb of the
hourglass, because of magnetic flux conservation, the dimming of the knot
occurs along with an adiabatic expansion of its cross section. A similar broken
exponential function could fit the TeV peaks in M87, which may imply a
correlation between the TeV flares of M87 and the light curves from radio to
X-ray in HST-1. The Very Large Array (VLA) 22 GHz radio light curve of HST-1
verifies our prediction based on the model fit to the main peak of the VLA 15
GHz radio light curve.Comment: 14 pages, 2 figures, accepted for publication in A
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Non-destructive evaluation of polymer coating structures on pharmaceutical pellets using full-field optical coherence tomography.
Full-field optical coherence tomography (FF-OCT) using a conventional light-emitting diode and a complementary metal-oxide semiconductor camera has been developed for characterising coatings on small pellet samples. A set of en-face images covering an area of 700 × 700 μm(2) was taken over a depth range of 166 μm. The three-dimensional structural information, such as the coating thickness and uniformity, was subsequently obtained by analysis of the recorded en-face images. Drug-loaded pharmaceutical sustained-release pellets with two coating layers and of a sub-millimetre diameter were studied to demonstrate the usefulness of the developed system. We have shown that both coatings can be clearly resolved and the thickness was determined to be 40 and 50 μm for the outer and inner coating layers, respectively. It was also found that the outer coating layer is relatively uniform, whereas the inner coating layer has many particle-like features. X-ray computed microtomography measurements carried out on the same pellet sample confirmed all these findings. The presented FF-OCT approach is inexpensive and has better spatial resolution compared with other non-destructive analysis techniques such as terahertz pulsed imaging, and is thus considered advantageous for the quantitative analysis of thin coatings on small pellet samples.This is the pre-peer reviewed version of the following article: Li, C., Zeitler, J. A., Dong, Y. and Shen, Y.-C. (2014), Non-Destructive Evaluation of Polymer Coating Structures on Pharmaceutical Pellets Using Full-Field Optical Coherence Tomography. J. Pharm. Sci., 103: 161-166. doi: 10.1002/jps.23764, which has been published in final form at http://onlinelibrary.wiley.com/doi/10.1002/jps.23764/abstrac
Research on BOM Mapping transformation for Ship Construction Process
Abstract: Due to the problem about the core departmental "information isolated island" with BOM, various stages of ship product design section are convergence off and impeded the construction of agile ship the product. In this paper, first, establish the various stages of the ship product BOM structure model, based on a comparison of the structural model analysis, design a more practical conversion method, and then describe the conversion process about the ship product life cycle BOM view in order to quickly build a variety of BOM view.
Keywords: BOM; BOM tectonic model; BOM view of conversio
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