Cheon-Seok Park

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—In this brief, we present a 60-W power amplifier that is linearized using an RF predistorter for multicarrier wideband code-division multiple-access (WCDMA) applications. The proposed RF predistorter is fully composed of RF or analog circuits, and it has a moderate memory effect compensation capability using a delayed third-order intermodulation (IM3)(More)
Arbutins (α- and β-arbutins) are glycosylated hydroquinones that are commercially used in the cosmetic industry. These compounds have an inhibitory function against tyrosinase, a critical enzyme for generating pigments, which leads to the prevention of melanin formation, resulting in a whitening effect on the skin. Although β-arbutin is found in various(More)
—This paper presents a new adaptive leakage canceler based on a direct leaky coupling method for an RF front-end circuit of an ultrahigh-frequency radio-frequency identication (UHF RFID) reader. For better receiver sensitivity, the leakage signal from a transmitter (TX) to a receiver (RX) should be suppressed. Compared with conventional methods, the(More)
The deduced amino acid sequence from a gene of the hyperthermophilic archaeon Pyrococcus sp. ST04 (Py04_0872) contained a conserved glycoside hydrolase family 57 (GH57) motif, but showed <13 % sequence identity with other known Pyrococcus GH57 enzymes, such as 4-α-glucanotransferase (EC, amylopullulanase (EC, and branching enzyme (EC(More)
α-Arbutin (α-Ab) is a powerful skin whitening agent that blocks epidermal melanin biosynthesis by inhibiting the enzymatic oxidation of tyrosine and l-3,4-dihydroxyphenylalanine (l-DOPA). α-Ab was effectively synthesized from hydroquinone (HQ) by enzymatic biotransformation using amylosucrase (ASase). The ASase gene from Deinococcus geothermalis (DGAS) was(More)
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