Jeongwoo Lee

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This paper presents the design of a fully-integrated CMOS frequency synthesizer for PCS- and cellular-CDMA wireless systems. The proposed charge-averaging charge pump scheme suppresses fractional spurs and the VCO combined with coarse tuning improves phase noise characteristics. The improved architecture of the dual-path loop filter makes it possible to(More)
A fully integrated dual-band frequency synthesizer in 0.35 /spl mu/m CMOS technology achieves a phase noise of -141 dBc/Hz at 1.25 MHz offset in the PCS band with a reference frequency doubler. Fractional spurs are reduced by 8.6 dB at 50 kHz offset with a replica compensated charge pump.
The frequency synthesizer with two LC-VCOs is fully integrated in a 0.35-/spl mu/m CMOS technology. In supporting dual bands, all building blocks except VCOs are shared. A current compensation scheme using a replica charge pump improves the linearity of the frequency synthesizer and, thus, suppresses spurious tones. To reduce the quantization noise from a(More)
STUDY OBJECTIVE To evaluate the reliability of assessments of nasal flow rate for improved nostril selection for nasotracheal intubation. DESIGN Prospective, randomized, double-blinded study. SETTING Operating room of a university-affiliated hospital. PATIENTS 118 ASA physical status 1 and 2 patients, aged 18-65 years, scheduled for elective(More)
BACKGROUND We performed this study to determine the beneficial effects of viewing an animated cartoon and playing with a favorite toy on preoperative anxiety in children aged 3 to 7 years in the operating room before anesthesia induction. METHODS One hundred thirty children aged 3 to 7 years with ASA physical status I or II were enrolled. Subjects were(More)
Silica nanotubes were synthesized using the multi-walled carbon nanotubes (MWCNTs) as the template material. First, we prepared silica coated MWCNT composites by surface oxidation of MWCNTs using KMnO(4) in the presence of a phase transfer catalyst and followed by grafting of 2-aminoethyl 3-aminopropyl trimethoxy silane, AEAPS. The amine groups in grafted(More)
Core-polystyrene/shell-silica nanocomposite particles are synthesized by simple soap-free emulsion polymerization employing positively charged silica sol. The polymerization is initiated with conventional anionic KPS. It is found that the silica sol should be added after the initiation and nucleation of the soap-free emulsion polymerization in order to(More)
As models for the physical properties of the corona above solar active regions grow more sophisticated, we will require better means for testing them. In this paper we discuss and apply such a test to a magnetic eld model for an active region. This test is based on the expectation that the temperatures at diierent points on a given magnetic eld line should(More)
Polymerization-induced phase separation of nanoparticle-filled solution is demonstrated as a simple approach to control the structure of porous composites. These composites are subsequently demonstrated as the active component for sodium ion battery anode. To synthesize the composites, we dissolved/dispersed titanium oxide (anatase) nanoparticles (for(More)
A systematic motion of Ha kernels during solar Ñares can be regarded as the chromospheric signature of progressive magnetic reconnection in the corona, in that the magnetic Ðeld lines swept through by the kernel motion are those connected to the di†usion region at the reconnection point. In this paper, we present high-cadence and high-resolution Ha[1.3(More)