On the Galactic Disk Metallicity Distribution from Open Clusters I. New   Catalogues and Abundance Gradient
  In this paper we have compiled two new open cluster catalogues. In the first one, there are 119 objects with ages, distances and metallicities available, while in the second one, 144 objects have both absolute proper motion and radial velocity data, of which 45 clusters also with metallicity data available. Taking advantages of the large number of objects included in our sample, we present an iron radial gradient of about -0.063$\pm$0.008 dex/kpc from the first sample. By dividing clusters into age groups, we show that iron gradient was steeper in the past, which is consistent with the recent result from Galactic planetary nebulae data, and also consistent with the inside-out galactic disk formation scenarios. Based on the cluster sample, we also discussed the metallicity distribution, cluster kinematics and space distribution. A disk age-metallicity relation could be implied from those properties, although we could not give conclusive result from the age metallicity diagram based on the current sample. More observations are needed for metal poor clusters. 
L. Chen, J.L. Hou, J.J. Wang (Shanghai Astronomical Observatory, CAS,   China)