J. C. Chi

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Presbycusis, a bilateral sensorineural hearing loss caused by changes in the inner ear, is related to multiple factors such as noise exposure and otologic disease. In institute-based studies, we tried to determine the incidence of presbycusis in Korean populations living in Seoul, Kyunggi and Kangwon provinces by gender and age groups. The subjects were(More)
Using semiconductor optical amplifier (SOA) as gain medium and active mode-locker, and a dispersion-compensating fibre (DCF) to manage cavity dispersion as well as to control and remedy pulse shape, we report an all-optical clock recovery device capable of continuously recovering the clock frequency of optical return-to-zero (RZ) signals with 10 to 12.5 GHz(More)
Access to the full text of the published version may require a subscription. formatting, and other quality control mechanisms may not be reflected in this document. Changes may have been made to this ABSTRACT Understanding the usage of the geographic information system (GIS) among geography teachers is a crucial step in evaluating the current dissemination(More)
A fiber ring laser with a semiconductor optical amplifier (SOA) as active component is investigated using a hybrid model. The SOA is studied using a newly-established 4<sup>th</sup>-order time-domain algorithm, which includes the nonlinear effects of carrier depletion and recovery, as well as gain dispersion. Comparison with existing analytical results(More)
With the prevalence of about 3&#x025; in the general Chinese population, peripheral arterial disease (PAD) has become a serious health issue. To address this issue, vessel wall imaging techniques have been introduced to assess the burden of PAD in terms of vessel wall thickness, area or volume. Recent advances in a 3D black-blood MRI sequence known as the(More)
The paper presents a comparison of the performance of undoped and modulation-doped AlGaN/GaN HFET devices over temperature. The results obtained indicate that the device structure has a significant influence on the device performance. The modulation-doped devices are superior to the undoped devices over the temperatures studied. The stability (the(More)
In conclusion, two channel simultaneous transmission is realized using direct coupling between pitch-matched VCSEL array and multicore fiber. The transmission capacity can be upgraded by using specifically designed VCSELs and fibers (e.g. 3/spl times/3 or 4/spl times/4 arrays) or possibly by 1.3-1.6 /spl mu/m light sources. These results show that the(More)
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