Extended Emission of Short Gamma-Ray Bursts

Preliminary results of our analysis on the extended emission of short/medium duration GRBs observed with Swift/BAT are presented. The Bayesian blocks algorithm is used to analyze the burst durations and the temporal structure of the lightcurves in different energy bands. We show here the results of three bursts (GRBs 050724, 061006 and 070714B) that have a prominent soft extended emission component in our sample. The extended emission of these bursts is a continuous, flickering-liked component, lasting $\sim 100$ seconds post the GRB trigger at 15-25 keV bands. Without considering this component, the three bursts are classified as short GRBs, with $T_{90}=2\sim 3$ seconds. GRB 060614 has an emission component similar to the extended emission, but this component has pulse-liked structure, possibly indicating that this emission component is different from that observed in GRBs 050724, 061006, and 070714B. Further analysis on the spectral evolution behavior of the extended emission component is on going.Comment: 2008 Nanjing GRB Conferenc

Spectrum-Efficient Triple-Layer Hybrid Optical OFDM for IM/DD-Based Optical Wireless Communications

In this paper, a triple-layer hybrid optical orthogonal frequency division multiplexing (THO-OFDM) for intensity modulation with direct detection (IM/DD) systems with a high spectral efficiency is proposed. We combine N-point asymmetrically clipped optical orthogonal frequency division multiplexing (ACO-OFDM), N/2-point ACO-OFDM, and N/2-point pulse amplitude modulated discrete multitoned (PAM-DMT) in a single frame for simultaneous transmission. The time- and frequency-domain demodulation methods are introduced by fully exploiting the special structure of the proposed THO-OFDM. Theoretical analysis show that, the proposed THO-OFDM can reach the spectral efficiency limit of the conventional layered ACO-OFDM (LACO-OFDM). Simulation results demonstrate that, the time-domain receiver offers improved bit error rate (BER) performance compared with the frequency-domain with ∼40% reduced computation complexity when using 512 subcarriers. Furthermore, we show a 3 dB improvement in the peak-to-average power ratio (PAPR) compared with LACO-OFDM for the same three layers

Large Magnetoresistance over an Extended Temperature Regime in Monophosphides of Tantalum and Niobium

We report extremely large magnetoresistance (MR) in an extended temperature regime from 1.5 K to 300 K in non-magnetic binary compounds TaP and NbP. TaP exhibits linear MR around $1.8\times 10^4$ at 2 K in a magnetic field of 9 Tesla, which further follows its linearity up to $1.4\times 10^5$ in a magnetic field of 56 Tesla at 1.5 K. At room temperature the MR for TaP and NbP follows a power law of the exponent about $1.5$ with the values larger than $300\%$ in a magnetic field of 9 Tesla. Such large MR in a wide temperature regime is not likely only due to a resonance of the electron-hole balance, but indicates a complicated mechanism underneath.Comment: 13 pages, 4 figures; submitted in May 20, 2015; accepted for publicatio

Exploring Green Innovation Practices: Content Analysis of the Fortune Global 500 Companies

Green innovation has been attracting increasing attention due to its contributions to the conservation of resources and environmental protection. However, in the process of exploring green innovation, the allocation of resources and the direction of innovation are often inaccurate, which leads to a low efficiency of green innovation. If we can learn the green innovation practices from successful companies, we can certainly provide reference strategies for those companies that are exploring green innovation. Therefore, taking the Fortune Global 500 companies as the analysis object, this research develops the criteria of green innovation practices and conducts a cluster analysis of these companies by using a content analysis method. Finally, this paper summarizes the green innovation practices of the six types of industries and provides corresponding countermeasures and suggestions, which provide a strong reference for relevant companies to carry out green innovation