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We report transport measurements on Josephson junctions consisting of Bi2Te3 topological insulator (TI) thin films contacted by superconducting Nb electrodes. For a device with junction length L = 134 nm, the critical supercurrent Ic can be modulated by an electrical gate which tunes the carrier type and density of the TI film. Ic can reach a minimum when the TI is near the charge neutrality regime with the Fermi energy lying close to the Dirac point of the surface state. In the p-type regime the Josephson current can be well described by a short ballistic junction model. In the n-type regime the junction is ballistic at 0.7 K < T < 3.8 K while for T < 0.7 K the diffusive bulk modes emerge and contribute a larger Ic than the ballistic model. We attribute the lack of diffusive bulk modes in the p-type regime to the formation of p-n junctions. Our work provides new clues for search of Majorana zero mode in TI-based superconducting devices., 6 pages, 4 figures, The manuscript with the same title will be published by Chinese Physics Letters

A new model for the linear magentoresistance (MR) of the Ag2+δSe and Ag2+δTe thin films is proposed. The thin him is considered as a metal-semiconductor composite and dispersed into an N – N quasi-random resistor network. The network is constructed from four-terminal resistors and the mobility of carries μ within the network has a quasi-random distribution, i.e. a Gaussian distribution with two constraint conditions. The model predicts that the MR increases with the increasing magnetic fields, and increases linearly at high field. Moreover, the MR decreases with the increasing temperatures. A good agreement between the theoretical MR and the available experimental data is found.

We study the circumstellar interaction around SN 1993J by its intermediate-band light curves obtained by the 60/90 cm Schmidt telescope at Xinglong station. The optical emission showed a slow decay of 0.05±0.02 mag/100 d in the period from 1995 to 2003, invoking a main energy contribution from SN-circumstellar interaction at late times. The relatively flat power law SN density model fits better with the observations. In particular, the line ratio of [O III]λλ4959, 5007 and Na I D relative to Hα are well reproduced by the model. Moreover, the Hα light curve displayed obvious bump structures at some epochs, which is probably attributed to the density fluctuations in the ambient material that surrounds the reverse shockwave.

Recently, the distances to type Ia supernova (SN Ia) at z~0.5 have been measured with the motivation of estimating cosmological parameters. However, different sleuthing techniques tend to give inconsistent measurements for SN Ia distances (~0.3 mag), which significantly affects the determination of cosmological parameters. A Bayesian ``hyper-parameter'' procedure is used to analyse jointly the current SN Ia data, which considers the relative weights of different datasets. For a flat Universe, the combining analysis yields ΩM = 0.20±0.07.

The single photon scattering properties in a pair of waveguides coupled by a whispering-gallery resonator interacting with a semiconductor quantum dot are investigated theoretically. The two waveguides support four possible ports for an incident single photon. The quantum dot is considered a V-type system. The incident direction-dependent single photon scattering properties are studied and equal-output probability from the four ports for a single photon incident is discussed. The influences of backscattering between the two modes of the whispering-gallery resonator for incident direction-dependent single photon scattering properties are also presented.

A Bayesian approach is used to derive the probability distribution (PD) of the Hubble constant H 0 from recent measurements including supernovae Ia, the Tully-Fisher relation, population II and physical methods. The discrepancies among these PDs are briefly discussed. The combined value of all the measurements is obtained, with a 95% confidence interval of 58.7

A new nuclide 239Pa was produced by 50 MeV/u 18O bombardment of natural uranium via multi-nucleon transfer reactions (238U-1p+2n). Protactinium was chemically separated from the uranium target and other produced elements. Then in that chemical fraction the growth and decay of 239U gamma rays were observed, identifying the 239U parent as 239Pa. Subsequent to 239Pa β- decay, with a half-life of 106±30 min, gamma rays of 522.0, 562.0, 638.5 and 681.0 keV were also observed.

A new nuclide 238Th was produced via multinucleon transfer reaction by 60 MeV/u 18O ion irradiation of the natural uranium. The thorium was radiochemically separated from the mixture of uranium and reaction products. The growth and decay of 238Pa gamma rays was observed, identifying the 238Pa parent as 238Th. The half-life of 238Th was determined to be 9.4±2.0 min.

The new neutron-rich isotope 186Hf has been produced through a multinucleon transfer reaction by irradiation of natural tungsten targets with 60 MeV/u 18O projectiles. The 186Hf activities were separated radiochemically from the tungsten and reaction product mixture. The γ-ray singles spectra were measured with a high resolution HPGe detector. The new isotope 186Hf was identified based on the growth and decay of 737.5 keV γ rays from the β- decay of its daughter 186Ta. Its half-life has been determined to be 2.6 ± 1.2 min.

Radioisotope of Pa-230 was synthesized by proton irradiation of ThO2 powder targets with thickness of about 2g/cm(2). Pure Pa-230 was extracted and deep purified from thorium and fission products by the radiochemical method. Thin Pa-230 beta(-)/--> U-230 sources were prepared for measuring the cluster decay of U-230. Two cases of decay via heavy ion emission, which were most probably for the neon decays of U-230, were detected by using solid-state track registration detectors. The preliminary branching ration relative to alpha-decay comes out to be (1.3 +/- 0.8) x 10(-14).