A New Lower Bound for the Distinct Distance Constant

The reciprocal sum of Zhang sequence is not equal to the Distinct Distance Constant. This note introduces a $B_2$-sequence with larger reciprocal sum, and provides a more precise estimation of the reciprocal sums of Mian-Chowla sequence and Zhang sequence.Comment: 4 pages, 3 ancillary table

Timing, glitches and braking index of PSR B0540-69

We report a pulse-time history of PSR B0540$-$69 based on the analysis of an extended Data set including ASCA, BeppoSAX and RXTE observations spanning a time interval of about 8 years. This interval includes also the epoch of the glitch episode reported by Zhang et al. (2001). Our analysis shows the presence of a relevant timing noise and does not give a clear evidence of the glitch occurrence. We performed an accurate evaluation of the main timing parameters, $\nu$, $\dot{\nu}$ and $\ddot{\nu}$ and derived a mean braking index of $n=2.125\pm0.001$ quite different from the lower value found by Zhang et al. (2001), but in rather good agreement with other several values reported in the literature.Comment: 9 pages 5 figures, accepted by A&A, main journa

Yingjin Zhang. The city in modern Chinese literature and film : configurations of space, time, and gender

This article reviews the book The City in Modern Chinese Literature and Film: Configurations of Space, Time, and Gender written by Yingjin Zhang

Observations on the basic (G′/G)-expansion method for finding solutions to nonlinear evolution equations

The extended tanh-function expansion method for finding solutions to nonlinear evolution equations delivers solutions in a straightforward manner and in a neat and helpful form. On the other hand, the more recent but less efficient (G′/G)-expansion method delivers solutions in a rather cumbersome form. It is shown that these solutions are merely disguised forms of the solutions given by the earlier method so that the two methods are entirely equivalent. An unfortunate consequence of this observation is that, in many papers in which the (G′/G)-expansion method has been used, claims that 'new' solutions have been derived are often erroneous; the so-called 'new' solutions are merely disguised versions of previously known solutions

Cayley graphs generated by small degree polynomials over finite fields

We improve upper bounds of F. R. K. Chung and of M. Lu, D. Wan, L.-P. Wang, X.-D. Zhang on the diameter of some Cayley graphs constructed from polynomials over finite fields