Strongly screening electron capture rates of chromium isotopes in presupernova

Taking into account the effect of electron screening on the electron energy and electron capture threshold energy, by using the method of Shell-Model Monte Carlo and Random Phase Approximation theory, we investigate the strong electron screening capture rates of chromium isotopes according to the linear response theory screening model. The strong screening rates can decrease by about 40.43\% (e.g., for $^{60}$Cr at $T_9=3.44,Y_e=0.43$). Our conclusions may be helpful to the researches of supernova explosion and numerical simulation.Comment: 9 pages, 2 figures,Accepted for publication in Astronomy and Astrophysics (RAA

Searching for initial stage of massive star formation around the H II region G18.2-0.3

Sometimes the early star formation can be found in cold and dense molecular clouds, such as infrared dark cloud (IRDC). Considering star formation often occurs in clustered condition, HII regions may be triggering a new generation of star formation, so we can search for initial stage of massive star formation around HII regions. Based on that above, this work is to introduce one method of how to search for initial stage of massive star formation around HII regions. Towards one sample of the HII region G18.2-0.3, multiwavelength observations are carried out to investigate its physical condition. In contrast and analysis, we find three potential initial stages of massive star formation, suggesting that it is feasible to search for initial stage of massive star formation around HII regions.Comment: 15 pages, 8 figures, 5 tables. Accepted by Research in Astron. Astrophy

Investigation of a Side-polished Fiber MZI and Its Sensing Performance

A novel all-fiber Mach–Zehnder interferometer (MZI), which consists of lateral core fusion splicing of a short section of side-polished single mode fiber (SMF) between two SMFs was proposed and demonstrated. A simple fiber side-polished platform was built to control the side polished depth through a microscope. The sensitivity of the fiber MZI structure to the surrounding refractive index (RI) can be greatly improved with the increase of the side-polished depth, but has no effect on the temperature sensitivity. The sensor with a polished depth of 44.2 μm measured RI sensitivity up to -118.0 nm/RIU (RI unit) in the RI range from 1.333 to 1.387, which agrees well with simulation results by using the beam propagation method (BPM). In addition, the fiber MZI structure also can achieve simultaneous measurement of both RI and temperature. These results show its potential for use in-line fiber type sensing application

Development of compress air transportation (CAT) for alternative energy utilization

Compress Air Transportation (CAT) is a new concept of transportation that utilizes air as the source of energy. Work on alternative power system for vehicle is becoming very important for the future due to combination of high prices on fuel, emission factor and also the source of the current energy will eventually run out. Several advantages for utilizing air as the source of energy compared to other alternative energy sources makes it become the subject for this project. In this project, a simple transportation utilizing air as the source of energy has been developed. The main component of the engine of the CAT is a device called the "Air Impact Wrench" which can be purchased from local stores. The CAT was tested and analyzed for further studies on expanding this new technology

Variability of the giant X-ray bump in GRB 121027A and possible origin

The particular giant X-ray bump of GRB 121027A triggered by \emph{Swift} is quite different from the typical X-ray flares in gamma-ray bursts. There exhibit four parts of the observed structural variabilities in the rise and decay phase of the bump. Considering the quality of four parts of the data, we can only analyze the data from about 5300 s to about 6100 s in the bump using the stepwise filter correlation method (Gao et al. 2012), and find that the $86^{+5.9}_{-9.4}~\rm s$ periodic oscillation may exist, which is confirmed by the Lomb-Scargle method (Scargle 1982). Furthermore, a jet precession model (Liu et al. 2010) is proposed to account for such a variability.Comment: 5 pages, 3 figures, accepted for publication in MNRA

Experimental Long-Distance Decoy-State Quantum Key Distribution Based On Polarization Encoding

We demonstrate the decoy-state quantum key distribution (QKD) with one-way quantum communication in polarization space over 102km. Further, we simplify the experimental setup and use only one detector to implement the one-way decoy-state QKD over 75km, with the advantage to overcome the security loopholes due to the efficiency mismatch of detectors. Our experimental implementation can really offer the unconditionally secure final keys. We use 3 different intensities of 0, 0.2 and 0.6 for the pulses of source in our experiment. In order to eliminate the influences of polarization mode dispersion in the long-distance single-mode optical fiber, an automatic polarization compensation system is utilized to implement the active compensation.Comment: 4 pages,3 figure