Ping Shum

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OBJECTIVE Only scanty information on the prevalence of tardive dyskinesia in Chinese patients has been available. This study was undertaken to examine the prevalence of tardive dyskinesia, tardive dystonia, and respiratory dyskinesia in Chinese psychiatric patients in Hong Kong. METHOD All inpatients of a mental hospital in Hong Kong, except those in the(More)
We proposed a novel polarization maintaining air-core bandgap polymer fiber for terahertz (THz) wave guiding. The periodic arrangement of square holes with round corners in cladding offers bandgap effect for mode guiding. The guiding properties including transmission bandwidth, numerical aperture, phase-index birefringence, modal absorption loss and bend(More)
A novel two-dimensional (2-D) accelerometer based on three fiber Bragg gratings (FBGs) has been developed. Both the magnitude and the direction of the acceleration can be detected simultaneously. Preliminary experimental results show that high sensitivity of 1.23 nm/(m• s-2) and resolution of 0.0008 m/s2 have been achieved. Furthermore, it is(More)
The concept of (∈, ∈ ∨ q)-fuzzy h-ideals of hemirings is introduced and some characterizations are described. We show that a hemiring S is h-hemiregular if and only if for any (∈, ∈ ∨ q)-fuzzy right h-ideal F and (∈, ∈ ∨ q)-fuzzy left h-ideal G, F • 0.5 G = F ∩ 0.5 G. Finally, the concept of implication-based fuzzy h-ideals of hemirings is considered.
We experimentally demonstrate switchable temporal soliton generation from a thulium-doped fiber laser (TDFL), using carbon nanotubes as the mode-locker. With the help of residual polarization dependent loss of a wavelength division multiplexer, a weak nonlinear polarization rotation (NPR) effect can be achieved within the laser cavity, which may provide(More)
We demonstrate fiber torsion sensor based on twist-induced circular birefringence in unbalanced Mach-Zehnder interferometer with two dissimilar abrupt tapers in a short (~1.4cm) highly Er/Yb co-doped fiber for simultaneous measurements of twisting angle and direction.
We interpret physically the dynamics of resonant seed modulation instability of quasi-continuous picosecond pulses in terms of cascaded four-wave mixing and Bragg scattering. We also report a critical condition to excite the resonant seeding effect.