• The Transactions of the Korean Institute of Power Electronics
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• v.10 no.2
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• pp.109-116
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• 2005

The high performance drives of the slotless Permanent Magnet Brushless DC(PM BLDC) motor can be achieved by the current control, where the currents flow according to the rotor position and the current phase is suitably controlled according to the operational condition. Rotor position information can be provided by Hall-IC or sensorless algorithm. So, the Hall-ICs are set up in this motor to detect the main flux from the rotor. Instead of using three Hall-ICs and encoder, this paper uses only two Hall-ICs for the permanent magnet rotor position and the speed feedback signals, and uses a micro-controller of 16-bit type (80C196KC). Also because of low resolution obtained by using Hall-IC even low-cost and simple structure, to improve the wide range of speed response characteristic more exactly, we propose the rotor position signal synthesizer using PLL circuit based on two Hall-ICs.

• Journal of Advanced Navigation Technology
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• v.22 no.2
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• pp.148-153
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• 2018

This paper proposes a single-input multiple-output (SIMO) self-resonant wireless power transmission system for transmitting power to multiple receivers and the characteristics are simulated and measured. A 600 mm diameter transmission single loop, a 600 mm diameter helical transmission resonant coil, an external diameter 900 mm planar spiral reception resonant coil, and an $80{\times}60mm^2$ flat plate square coil as a receiver are used to form a wireless power transmission system 600 mm away with the table structure. For optimal characteristics, the wireless power transmission coils are designed by EM simulation and equivalent circuit analysis, and the characteristics are simulated and measured. The variation of the efficiency with distance from the center of the spiral resonant coil is analyzed and the measured efficiency is 57% for one receiver and for the two receivers, the efficiency is 37% for each receiver.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.18 no.7
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• pp.839-846
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• 2007

In this paper, the first attempt to design a novel structure of dual-band feedforward linear power amplifier(FFW LPA) was presented. Up to now, primary technical difficulty has been the extension of the conventional signal canceller to the dual-band operation. Therefore, we propose the design technique of the dual-band equal group delayed carrier canceller, the dual-band equal group delayed intermodulation distortion(IMD) canceller and the dual-band FFW LPA. The operation frequency bands of the implemented dual-band FFW LPA are digital cellular($f_0=880$ MHz) and IMT-2000($f_0=2.14$ GHz) band, which are separated about 1.26 GHz. With the high power amplifier of 120 W PEP for commercial base-station application, IMD cancellation loop shows 20.45 dB and 25.04 dB loop suppression at each band of operation for 100 MHz. From the adjacent channel leakage ratio(ACLR) measurement with CDMA IS-95A 4FA and WCDMA 4FA signal, we obtained 16.52 dB improvement at the average output power of 41.5 dBm for digital cellular band, and 18.59 dB improvement at the average output power of 40 dBm for IMT-2000 band simultaneously.

• Korean Journal of Microbiology
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• v.48 no.2
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• pp.79-86
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• 2012

ErmSF is one of the Erm family proteins which catalyze S-adenosyl-$_L$-methionine dependent modification of a specific adenine residue (A2058, E. coli numbering) in bacterial 23S rRNA, thereby conferring resistance to clinically important macrolide, lincosamide and streptogramin B ($MLS_B$) antibiotics. $^{222}FXPXPXVXS^{230}$ (ErmSF numbering) sequence appears to be a consensus sequence among the Erm family. This sequence was supposed to be involved in direct interaction with the target adenine from the structural studies of Erm protein ErmC'. But in DNA methyltarnsferase M. Taq I, this interaction have been identified biochemically and from the complex structure with substrate. Arginine 223 and 227 in this sequence are not conserved among Erm proteins, but because of the basic nature of residues, it was expected to interact with RNA substrates. Two amino acid residues were replaced with Ala by site-directed mutagenesis. Two mutant proteins still maintained its activity in vivo and resistant to the antibiotic erythromycin. Compared to the wild-type ErmSF, R223A and R227A proteins retained about 50% and 88% of activity in vitro, respectively. Even though those arginine residues are not essential in the catalytic step, with their positive charge they may play an important role for RNA binding.

• Journal of the Korean Magnetics Society
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• v.2 no.3
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• pp.251-256
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• 1992

Artificial superlattices of Co/Pd were prepared by RF magnetron sputtering Multilayered structure and compositional modulation were analyzed with a side angle x-ray diffractometer. It has been found that expansion of Co lattice occured in this artificial superlattice due to the lattice mismatch between Co and Pd. Perpendicular magnetic anisotropy could be observed when the Co layer thickness became less than 8${\AA}$ and maximum coercivity of 2350 Oe could be obtained in [Co(2.5 ${\AA}$)/Pd(9.3 ${\AA})]_{50}$/Pd$(200\;{\AA})$ with a perfect squareness of magnetic hysteresis loop. Characteristic of perpendicular magnetic anisotropy in Co/Pd superlattices could be related to the expansion of Co lattice caused by Pd layer and it turned out that as the thickness of Pd layer increased, perpendicular magnetic anisotropy increased. The interface anisotropy energy and volume anisotropy energy were calculated to be 0.29 ergs/$cm^2$ and -$6.9{\times}10^6$ ergs/$cm^3$ respectively, which are consistent with the values reported elsewhere.

• Korean Journal of Poultry Science
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• v.45 no.3
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• pp.209-217
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• 2018

The innate immune recognition is based on the detection of microbial products. Toll-like receptors (TLRs) located on the cell surface and the endosome senses microbial components and nucleic acids, respectively. Chicken TLRs mediate immune responses by sensing ligands from pathogens, have been studied as immune adjuvants to increase the efficacy of vaccines. Single nucleotide polymorphisms (SNPs) of TLR3 and TLR4 genes in chicken were associated with resistance and susceptibility to viral infection. In this study, SNPs of chTLR3 and chTLR4 genes were retrieved from public database and annotated with chicken reference genome. Three-dimensional models of the chTLR3 and chTLR4 proteins were built using a Swiss modeler. We identified 35 and 13 nsSNPs in chTLR3 and chTLR4 genes respectively. Sorting Intolerant from Tolerant (SIFT) and Polymorphism Phenotyping v2 (Polyphen-2) analyses, suggested that, out of 35 and 13 nsSNPs, 4 and 2 SNPs were identified to be deleterious in chTLR3 and chTLR4 gene respectively. In chTLR3, 1 deleterious SNP was located in ectodomain and 3 were located in the Toll / IL-1 receptor (TIR) domain. Further structural model of chTLR3-TIR domain suggested that 1 deleterious SNP be present in the B-B loop region, which is important for TIR-TIR domain interactions in the downstream signaling. In chTLR4, the deleterious SNPs were located both in the ectodomain and TIR domain. SNPs predicted for chTLR3 and chTLR4 in this study, might be related to resistance or susceptible to viral infection in chickens. Results from this study will be useful to develop the effective measures in chicken against infectious diseases.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.39 no.12
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• pp.1237-1244
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• 2015

A gerotor can be manufactured in a miniature size because it has a high discharge per cycle and a simple structure. Gerotors are widely used for the lubrication oil of an engine and as the hydraulic source of an automatic transmission. Recently, improvements in fuel efficiency and noise reduction have come to the fore in the automobile industry, and it has been necessary for better fuel efficiency to continuously improve the flow rate and noise of internal gear pumps through the optimal design of the gerotor and port shape. In this study, gerotors were generated based on the equations derived for a lobe shape with multiple profiles (ellipse 1-elliptical involute-ellipse 2). The ranges of the design parameters were considered to prevent a cusp and loop. In addition, the optimal lobe shape was obtained by determining the influence of the lobe shape on the performances (flow rate, irregularity, etc.), according to the values of the design parameters.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2004.07b
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• pp.960-964
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• 2004

[ $Ba_2NaNb_5O_{15}$ ](BNN) thin films have been prepared by the ion beam sputter deposition (IBSD) method on Pt coated Si substrate at temperature as low as $600^{\circ}C$ XRD, SEM were used to investigate the crystallization and microstructure of the films. It was found that the films were crack-free and uniform in microstructure. The electric properties of thin films were carried out by observation of D-E hysteresis loop, dielectric constant and leakage current. It was found the deposition rate strongly influenced the phase formation of the films, where the phase of $BaNb_2O_6$ was always formed when the deposition rate was high. However, the single phase (tungsten bronze structure ) BNN thin film was obtained with the deposition rate as low as $22{\AA}/min$. The remanent polarization Pr and dielectric constant are about 1-2 ${\mu}C/cm^2$ and $100\sim200$, respectively. It was also founded the electric properties of thin films were influenced by the deposition rate. The Pr and dielectric constant of films increased with the decrease of deposition rate. The effects of annealing temperature and annealing time to the crystallization behavior of films were studied. The crystallization of thin film started at about $600^{\circ}C$. The adequate crystallization was gotten at the temperature of $650^{\circ}C$ when the annealing time is 0.5 hour or at the temperature of $600^{\circ}C$ when the annealing time is long as 6 hours.

• Journal of Korea Society of Industrial Information Systems
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• v.19 no.4
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• pp.17-24
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• 2014

In this paper, we propose a CMOS FM RX front-end structure with an automatic tunable input matching network and implement it using a 65nm CMOS technology. The proposed FM RX front-end is designed to change the resonance frequency of the input matching network at the low noise amplifier (LNA) according to the channel frequency selected by a phase-locked loop (PLL) for maintaining almost constant sensitivity level when an embedded antenna type with high frequency selectivity characteristic is used for FM receiver. The simulation results of implemented FM front-end show about 38dB of voltage gain, below 2.5dB of noise figure, and -15.5dBm of input referred intercept point (IIP3) respectively, while drawing only 3.5mA from 1.8V supply voltage including an LO buffer.

• Journal of the Institute of Electronics Engineers of Korea SD
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• v.38 no.11
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• pp.765-770
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• 2001

Metal-ferroelectric-insulator- semiconductor(MFTS) devices by using rapid thermal annealed (RTA) LiNbO$_3$/AIN/Si(100) structures were successfully fabricated and demonstrated nonvolatile memory operations. Metal-insulator-semiconductor(MIS) C-V properties with high dielectric AIN thin films showed no hysteresis and good interface properties. The dielectric constant of the AIN film calculated from the capacitance at the accumulation region in the capacitance-voltage(C-V) characteristics was about 8. The C-V characteristics of MFIS capacitor showed a hysteresis loop due to the ferroelectric nature of the LiNbO$_3$ thin films. Typical dielectric constant value of LiNbO$_3$ film of MFIS device was about 23. The memory window width was about 1.2 V at the gate voltage of $\pm$5 V ranges. Typical gate leakage current density of the MFIS structure was the order of 10$^{-9}$ A/$\textrm{cm}^2$ at the range of within $\pm$500 kV/cm. The ferroelectric capacitors showed no polarization degradation up to about 10$^{11}$ switching cycles when subjected to symmetric bipolar voltage pulse(peak-to-peak 8 V, 50 % duty cycle) in the 500 kHz.