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)
All-optical clock recovery (CR) from 10 Gbps non-return-to-zero differential phase-shift-keying (NRZ-DPSK) signal is demonstrated experimentally, with the chromatic dispersion induced clock tone and semiconductor optical amplifier (SOA)-based mode-locked fiber ring laser. The good performance of our proposed configuration is fulfilled with a 20 km standard(More)
We report, for the first time to our knowledge, the presence of concentration-induced nonuniform power in tunable erbium-doped fiber lasers. A theoretical model is proposed with pair-induced quenching taken into account. We obtain good agreement between numerical and experimental results of a high-concentration erbium-doped fiber ring laser with a large(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.
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)
A selective-broadcasting scheme for WDM-PON based fiber access networks is proposed and demonstrated in this paper. The broadcasting data is generated via subcarrier modulation technique. By using an asymmetrical Mach-Zehnder interferometer (MZI), the un-modulated continuous-wave carrier is separated and acts as a seeder for the Fabry-Perot laser diode(More)
A simple sensor head based on a single fiber Bragg grating (FBG) for simultaneous measurement of strain and temperature is proposed. The FBG, inscribed on the fusion splicing joint region between a single-mode fiber and a side-hole fiber, has two Bragg resonant wavelengths, which respond differently to strain and temperature. Strain-temperature(More)