Forecast of China’s grain production development and its self-support rate analysis

This paper discuses four stern difficulties and challenges faced by the development of grain production in China. According to the basic national conditions of China and the amount of grain resources in the world market, China must meet the grain demands mainly by her own domestic production. Using the input-occupancy-output techniques and system science methods, this paper makes a forecast about China’s grain output, grain import and self-support rate in the year 2030. The research was supported by the National Natural Science Foundation of China.     

Relative astrometry and near‐infrared differential photometry of nearby southern orbital binaries with adaptive optics

We present relative astrometry and differential photometry measurements for a sample of nearby southern orbital binaries making use of the technique of Adaptive Optics. The observations were made in December 2000, with the ADONIS camera mounted at the 3.6‐m ESO telescope from La Silla Observatory, equipped with the broad‐band near‐infrared filters (J ‐, H ‐, K ‐passbands). Our sample contains stars which do not fit very well the empirical mean mass‐luminosity relation (according to our previous study), but for which accurate parallaxes (determined by the Hipparcos satellite) and high‐quality orbits were available thanks to many previous efforts. We derived accurate positions and J, H, K magnitudes of the individual components of those binaries. The individual stellar components have near‐infrared colour indices well grouped in those plots and are comparable to standard single stars. The data reduction procedure used for deriving those results is described in detail. It is based on a least‐squares fit of Moffat‐Lorentz profiles in direct imaging for well‐resolved systems and on Fourier analysis for very close pairs. (© 2013 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)     

One of the first members of RS CVn‐type systems: MM Herculis

We present the long‐term multi‐colour photometry of MM Her which is one of the first members of the RS CVn‐type of eclipsing binary systems. We took advantage of its photometry‐spanning 33 years to evaluate its long‐term variation, which is caused by the evolution of the activity structures located on the surface of the cooler component. In this study we found that the long‐term variation in the brightness, colour, and amplitude of seasonal light curves over the years could be represented by two periods: one of which is of around 22.5 years, and is similar to all in this regard, but the other is a period value of about 9.5 years for the brightness variation, and of about 7.5 years for the variation in colour and amplitude. The analysis of the spot minimum phases gives a migration period of approximately 7.8 years. We also presented a new light curve analysis solution, and improved its light elements in this study. (© 2013 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)     

Pulsation analysis of the high amplitude δ Scuti star CW Serpentis

Time-series photometric observations were made for the high amplitudeδScuti star CW Ser between 2011 and 2012 at the Xinglong Station of National Astronomical Observatories,Chinese Academy of Sciences.After performing the frequency analysis of the light curves,we confirmed the fundamental frequency of f=5.28677 c d 1,together with seven harmonics of the fundamental frequency,which are newly detected.No additional frequencies were detected.The O C diagram,produced with the 21 newly determined times of maximum light combined with those provided in the literature,helps to obtain a new ephemeris formula of the times of maximum light with the pulsation period of 0.189150355±0.000000003 d.