arXiv subjects

Kaicheng Zhang

Publications and source records attributed to Kaicheng Zhang.

39 records · Page 3Linked to original sources

arXiv2014

The THU-NAOC Transient Survey: the Performance and the First-year Result

The Tsinghua University-National Astronomical Observatories of China (NAOC) Transient Survey (TNTS) is an automatic survey for a systematic exploration of optical transients (OTs), conducted with a 60/90 cm Schmidt telescope at Xinglong station of NAOC. This survey repeatedly covers ~ 1000 square degrees of the north sky with a cadence of 3-4 days. With an exposure of 60 s, the survey reaches a limited unfiltered magnitude of about 19.5 mag. This enables us to discover supernovae at their relatively young stages. In this paper, we describe the overall performance of our survey during the first year and present some preliminary results.

astro-ph.IM↗

arXiv2006

Probe to properties of MgB2 thick film on silicon carbide substrate

We have successfully synthesized MgB2 thick films on 4H-SiC substrate by hybrid physical-chemical deposition (HPCVD). The films have transition temperature TC above 40 K. X-ray diffraction (XRD) shows the c-axis oriented structure of MgB2, with Mg and small MgO impurities. The critical current density JC, estimated using the measured magnetic hysteresis loop and the Bean model, is 6 MA/cm2 in self field at 10 K.

cond-mat.supr-con↗

arXiv2006

MgB2 thick film with TC = 40.2 K deposited on sapphire substrate

We have successfully deposited thick MgB2 film on the (0001) crystalline surface of sapphire by the method of hybrid physical-chemical vapor deposition (HPCVD). The film thickness is about 1.3 micron. It has a dense and interlaced structure. The film surface, shown by SEM, is stacked with MgB2 microcrystals. Transport measurements by the 4-probe technique have demonstrated that its critical temperature is about 40.2 K, with a sharp transition width of 0.15 K. The residual resistivity ratio (RRR) is about 11. By extrapolation, HC2(0) is determined as 13.7 T from the magneto-transport measurement. Also by hysteresis measurement and applying the Bean model, the critical current density is estimated as 5*1010 A/m2 in zero magnetic field. The present work has demonstrated that HPCVD is an effective technique to fabricate the MgB2 thick film with decent superconducting properties. Hence, it is important for the future superconducting application, in particular, as a crucial preliminary stage to fabricate superconducting tape.

cond-mat.supr-con↗