• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.18 no.11
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• pp.1262-1270
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• 2007

In this paper, we propose a new distortion cancellation mechanism for a balanced power amplifier structure using the carrier cancellation loop of a feedforward and post-distortion technique. The proposed cross post-distortion balanced linear amplifier can reduce nonlinear components as much as the conventional feedforward amplifier through the output dynamic range and broad bandwidth. Also the proposed system provides higher efficiency than the feedforward. The capacities of power amplifier and error power amplifier in the proposed system are analyzed and compared with those of feedforward amplifier. Also the operation mechanisms of the three kind loops are explained. The proposed cross post-distortion balanced linear power amplifier is implemented at the IMT-2000($f_0=2.14\;GHz$) band. With the commercial high power amplifiers of total power of 240 W peak envelope power fer base-station application, the adjacent channel leakage ratio measurement with wideband code division multiple access 4FA signal shows 18.6 dB improvement at an average output power of 40 dBm. The efficiency of fabricated amplifier Improves about 2 % than the conventional feedforward amplifier.

• The Journal of the Acoustical Society of Korea
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• v.13 no.6
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• pp.50-59
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• 1994

Spectral analysis of transient elastic waves were carried out in order to identify the propagation modes in glass and unidirectional carbon fibre reinforced plastic (CFRP) plates. Pencil leads were broken on the surface of plates to generate elastic waves, and two broad band transducers of 6.35 mm in diameter and 10 MHz center frequency were placed at the linear location from the source. The frequency spectra of detected signals showed that the wave propagation in the plates obeyed the Lamb wave dispersion relation. The transient signals were the fast propagating modes around maximum group velocity of the lowest and first order symmetric $modes(S_{0} and S_{1}),$ and first order antisymmetric $mode(A_{1})$. The transient signals were not severely distorted due to relatively small dispersion of those modes around the maximum group velocity. The fastest propagating mode in the plates was shown to be $S_{0}$ mode less the than cut-off frequency of $A_{1}$ mode.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.27 no.7
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• pp.477-482
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• 2014

$CaNb_2O_6:RE^{3+}$ (RE=Sm or Eu) phosphor powders were prepared with different contents of activator ions by using solid-state reaction method. The X-ray diffraction patterns exhibited that the phosphors synthesized with different activator ions showed an orthorhombic system with a main (131) diffraction peak. The maximum size of the grain particles, determined from the measurement of scanning electron microscopy, was observed at 0.05 mol of $Eu^{3+}$ ions and at 0.01 mol of $Sm^{3+}$. As for the $Eu^{3+}$-doped phosphor powders, the excitation spectra were composed of a broad band peaked at 278 nm and several weak bands in the range of 350~500 nm, and the highest red emission spectrum was observed at 0.15 mol of $Eu^{3+}$ ions. As for the $Sm^{3+}$-activated phosphor powders, three strong emission bands under excitation at 273 nm were observed at 570, 612, and 659 nm, respectively. The intensities of all the emission bands approached maxima for 0.05 mol of $Sm^{3+}$ ions. The optical properties show that the $Eu^{3+}$- or $Sm^{3+}$-doped $CaNb_2O_6$ powders are promising red-orange emitting phosphor powders applicable to full-color photonic devices.

• Journal of Microbiology and Biotechnology
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• v.24 no.2
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• pp.254-263
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• 2014

Enteromorpha polysaccharides (EP) extracted from green algae have displayed a wide variety of biological activities. However, their high molecular weight leads to a high viscosity and low solubility, and therefore, greatly restrains their application. To solve this problem, bacteria from the surface of Enteromorpha were screened, and an Alteromonas macleodii strain B7 was found to be able to decrease the molecular weight of EP in culture media. Proteins harvested from the supernatant of the A. macleodii B7 culture were subjected to native gel electrophoresis, and a band corresponding to the Enteromorpha polysaccharide lyase (EPL) was detected by activity staining. The enzyme identity was subsequently confirmed by MALDI-TOF/TOF mass spectrometry as the putative ${\alpha}$-amylase reported in A. macleodii ATCC 27126. The amylase gene (amySTU) from A. macleodii B7 was cloned into Escherichia coli, resulting in high-level expression of the recombinant enzyme with EP-degrading activity. AmySTU was found to be cold-adapted; however, its optimal enzyme activity was detected at $40^{\circ}C$. The ${\alpha}$-amylase was highly stable over a broad pH range (5.5-10) with the optimal pH at 7.5-8.0. The highest enzyme activity was detected when NaCl concentration was 2%, which dropped by 50% when the NaCl concentration was increased to 16%, showing an excellent nature of halotolerance. Furthermore, the amylase activity was not significantly affected by tested surfactants or the presence of some organic solvents. Therefore, the A. macleodii strain B7 and its ${\alpha}$-amylase can be useful in lowering EP molecular weight and in starch processing.

• Proceedings of the Korea Contents Association Conference
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• 2004.11a
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• pp.121-124
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• 2004

The Contemporary animation style based on technology become various within some categories and genres as recreating the importance and meaning of many formalities. According to the variation of the contemporary animation style, The computer animation that has affected on continuous development of science and its following broad-band culture takes charge of the important position in producing the contemporary visual art. On this thesis, I will research < Ani-matrix > which has 9 episode each for the different Matrix world focused on its animation style. I will analyze their forms of expression into the both aspects of esthetics viewpoint technologically and film making style traditionally regarding to the matter of reality and reemergence on a viewpoint of a realistically esthetics. Also I will analyze mutual connection among the reinterpretation for the reality, philosophical message, and animation style within < Ani-Matrix> suggested by influence of Post-modernism. Thus, I intend to prospect the formation of animation style followed by its esthetics construction and effect on computer animation of the film genre.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.12 no.2
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• pp.600-604
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• 2011

In this paper, the scintillation properties of $LaCl_3:Eu^{2+}$ crystal were investigated as new scintillator. This scintillation material was grown by a Czochralski method. $LaCl_3:Eu^{2+}$ was determined to have a hexagonal $P_63$/m space group with cell parameters a = b = $7.48{\AA}$, c = $4.37{\AA}$. Under 335 nm UV excitation, the crystal shows a broad emission band between 370 nm and 640 nm wavelength range, peaking at 430 nm. At room temperature, the crystal exhibits one exponential decay time component. The component of scintillation time profile of the crystal emission decays with a $2.82{\pm}0.72{\mu}s$ time constant. The energy resolution of the crystal was measured to be 8.8% (FWHM) for $^{137}Cs$ 662 keV ${\gamma}$-rays.

• Journal of Advanced Navigation Technology
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• v.15 no.6
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• pp.1241-1249
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• 2011

There are TOA, TDOA and AOA method to estimate the position of the electromagnetic wave transmitter by using the multiple receivers at the fixed position. Among these methods, AOA method is suitable for the jammer localization system. Because TOA method can be adopted for the clocks of the transmitter and the receiver are synchronized each other, and TDOA method can be only adopted for a broad-band jamming signal. This paper, therefore, analyzes the characteristics of the AOA measurements and the sensitivity of the positioning performance according to the system design parameters. Based on the analyzed results, the jammer localization system to meet the desired performance is designed, and it has been checked that the positioning error for the jammer located at a distance of 10km is lower than 38m through the simulation results.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.28 no.3
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• pp.32-43
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• 2014

This paper presents the intra capacitance modeling according to the winding method, section bobbin and coil structure for hybrid choke coil capable of the EMI attenuation of broad bands from lower frequency bands to higher frequency bands and high frequency type common-mode choke coil capable of the EMI attenuation of high frequency band used in the EMI Block of LED-TV SMPS. In case of high frequency type CM choke coil, it can be explained the parasitic capacitance of A type and section bobbin type winding methods among them is much smaller than the other. The first resonant frequency of the proposed CM choke coil tends to increase as the parasitic capacitance becomes small and its impedance characteristics also show improved performance as the first resonant frequency increases. In case of hybrid choke coil using rectangular copper wire, it has investigated its parasitic capacitance compared to CM choke coil of conventional toroidal type becomes small. Also it has confirmed through the experiment results that CE margin and RE margin in frequency bands 0.5MHz to 5MHz and 30MHz to 200MHz are respectively 10dB and 15dB greater than that of conventional type in case of one stage EMI filter structure adopting hybrid choke coil compared to two stage EMI Filter structure using two of each CM choke coil used in the lower and higher frequency bands or two of CM choke coil used in only the lower frequency bands. In the future, the hybrid choke coil and CM choke coil of high frequency type show it can be practically used in not only LED/LCD-TV SMPS but also several applications such as LED Lighting, Laptop Adapter, Server Power Supply and so on.

• The Transactions of the Korea Information Processing Society
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• v.4 no.6
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• pp.1589-1600
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• 1997

The construction of optical access network costs upper 40% in total installation cost of total optical network. Optimization of access network therefore is core in optical network. Advanced countries include EU, Japan and USA already have researched access network. This paper presents analysis of three broad-band fiber-optics subscriber loop architectures(HFC, ATM-PON, Super PON). The analyses focus on the specific demonstrated architectures and use component cost projections to estimate future network costs on a per-subscriber basis. We use TITAN(Tool for Introduction Scenarios and Techno-Economic Evaluation of The Access Network) model. We find that ATM-PON can deliver voice and ISDN data at installed first costs than the other architectures. This is due to the sharing bandwidth among a cluster of subscribers within Curb. This work intends to support establishing guidelines for strategic decisions regarding the development of the access network alternatives of different operators.

• Korean Journal of Veterinary Research
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• v.38 no.2
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• pp.328-335
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• 1998

Outer membrane proteins(OMPs) of Brucella abortus 1119-3 strain were extracted by Triton X-100 treatment, and fractionated by DEAE-cellulose column chromatography and Sephacryl S-300 column chromatography. The antigenic proteins in these fractions were identified by Western blot analysis. In Western blot analysis, a single band(38kDa) was observed in the DEAE fractions from 36th fraction to 38th fraction against sera of cattle infected with B abortus. And other fractions have several bands. However, the Sephacryl S-300 fractions exhibited a total of 3 peaks of proteins with a broad range from about 30 to 116kDa. In order to characterize further, the extracted OMPs and the DEAE fractions were analyzed by two dimensional polyacrylamide gel electrophoresis(2-DE) and Western blot using serum from naturally infected cattle with Brucella spp. The 2-DE immunoblots of DEAE fraction showed immunoreactive spots more than twenty two. The major protein spots have ranging from about 32 to 47kDa. The pI values of the spots were detected from pH 4.7 to 5.4. Among the major protein spots, the 38kDa protein which is a specific antigen, located at the point of approximately a pI 4.8.