  We report new spectroscopic results, obtained with UKIRT/CGS4, of a sample of
14 candidate ultracool dwarfs selected from the DENIS (Deep Near-Infrared
Survey of the Southern Sky) database. A further object, selected from the 2MASS
Second Incremental Release, was observed at a later epoch with the same
instrument. Six objects are already known in the literature; we re-derive their
properties. A further four prove to be very nearby (~10 pc) mid-to-late
L-dwarfs, three unknown hitherto, two of which are almost certainly substellar.
These findings increase the number of L-dwarfs known within ~10 pc by ~25%. The
remainder of the objects discussed here are early L or very late M-type dwarfs
lying between ~45 and 15 pc and are also new to the literature. Spectral types
have been derived by direct comparison with J-,H- and K- band spectra of known
template ultracool dwarfs given by Leggett et al.
(ftp://ftp.jach.hawaii.edu/pub/ukirt/skl/dL.spectra/) For the known objects, we
generally find agreement to within ~1 subclass with previously derived spectral
types. Distances are determined from the most recent M_J vs. spectral type
calibrations, and together with our derived proper motions yield kinematics for
most targets consistent with that expected for the disk population; for three
probable late M-dwarfs, membership of a dynamically older population is
postulated. The very nearby L-type objects discussed here are of great interest
for future studies of binarity and parallaxes.
