• Applied Biological Chemistry
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• v.38 no.2
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• pp.118-122
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• 1995

Escherichia Coli ornithine transcarbamylase is the enzyme which catalyzes the L-citrulline biosynthesis from L-ornithine and carbamyl phosphate. To facilitate the purification of enzyme which will be used for many biochemical studies such as structure and function relationships and catalytic mechanisms, the cloning and expression of E. coli argI gene for ornithine transcarbamylase was conducted. argI was amplified from genomic DNA of E. coli strain of $DH5{\alpha}$, by polymerization chain reaction (PCR) method. The amplified argI gene was ligated to the prokaryotic expression vector pKK223-3 and used for transformation of E. coli TB2 which was deficient of ornithine transcarbamylase. The over-produced enzyme by the tnansformant was purified by ammonium sulfate fractionation, heat denaturation and affinity chromatography. The result of SDS denaturation gel electrophoresis for the purified enzyme showed a single band of about 38 kDa of ornithine transcarbamylase. Kinetic data for the expressed enzyme gave almost the s?????? values as those of the wild type enzyme. The $k_{cat}$, of the enzyme was $1.0{\times}10^5min^{-1}$, and $K_ms$ for ornithine and carbamyl phosphate were 0.35 mM and 0.06 mM, respectively.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.34 no.11C
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• pp.1085-1097
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• 2009

We present a structure and design method of the D8PSK modem compatible with the VDL mode-2 standard and performance test results of the developed modem. In VDL mode-2, the raised cosine filter is used only in the transmitter and a general low pass filter is used in the receiver. Consequently, we can not achieve ISI reduction but can have better spectrum characteristics. Although there is 1~2 dB performance degradation with an un-matched filter compared to that with a matched filter, it is more important to minimize adjacent channel interference in narrow band communications. The transmit signal is generated digitally to avoid the problems(I/Q imbalance and DC offset etc.) of analog modulators. In addition the digital down converter using digital IF sampling technique is adopted for the receiver. This paper contains the overall configuration, design method and simulation results based in part on the previously proposed structures and algorithms. It is confirmed that the modem transmits and receives messages successfully at a speed of max. 870 km/h over ranges of up to 310 km through the ground and in-flight communication tests.

• Journal of the Korean Magnetics Society
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• v.6 no.6
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• pp.405-410
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• 1996

Valence band photoemission spectroscopy (PES) measurements have been performed for $Co_{x}Pd_{100-x}$ alloy films using synchrotron radiation (x = 0, 25, 40, 65). Then the partial spectral weight distributions (PSW's) of Co 3d and Pd 4d electrons have been determined. The Co 3d PSW's exhibit some structures which are quite different from those of the Co film for x < 25 %, whereas they become very similar to those of the Co film for x > 40 %. For x < 25 %, the peak near the Fermi level ($E_F$) and a shoulder around 2 eV binding energy in the Co 3d PSW reflect large hybridization between Pd 4d and Co 3d electrons, suggesting that the hybridization might play an inportant role in determining perpendicualr magnetic anisotropy. The Pd 4d PSW's in Co-Pd alloy films are found to have larger FWHM's (full widths at half maximum), larger binding energies of the main peaks, and larger spectral intensities at $E_F$ than the PES spectrum of the Pd film. The FWHM of the Pd 4d PSW increases with decreasing Pd concentration, which are considered to reflect the disordering effect in the alloy formation or the change in the Pd 4d electronic structure due to hybridization between Co 3d and Pd 4d electrons.

• Journal of the Korean Magnetics Society
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• v.25 no.6
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• pp.175-179
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• 2015

The half-metallicity and magnetism of the (001) surfaces of $(AlP)_1/(CrP)_1$ superlattice were investigated by means of FLAPW (Full-potential Liniarized Augmented Plane Wave) method. We considered four types of (001) surface termination, i.e., Al(S)-, Cr(S)-, P(S)Al(S-1)- and P(S)Cr(S-1)-term systems. We found that only Cr(S)-term system maintains the half-metallicity at the surface as only this system has the calculated magnetic moment of integer number of bohr magnetons. The magnetic moment of Cr(S) atom in the system was $3.02{\mu}_B$ which was increased from the bulk value by the effects of band narrowing and increased spin-splitting at the surface. The electronic density of states of the P(S) atom in the P(S)Al(S-1)-term showed very sharp surface states due to the broken $p_z$ bonds at the surface. We found there is still a strong p-d hybridization between the P(S) and Cr(S-1) layers in the P(S)Cr(S-1)-term which causes a considerable increase of magnetic moment of P(S) atom.

• Korean Journal of Optics and Photonics
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• v.19 no.1
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• pp.20-24
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• 2008

A color filter was proposed and demonstrated by incorporating a subwavelength patterned 1-dimensional grating in poly silicon. It was produced by employing the laser interference lithography method, providing much wider effective area compared to the conventional e-beam lithography. A $SiO_2$ layer was introduced on top of the silicon grating layer as a mask for the etching of the silicon, facilitating the etching of the silicon layer. It was theoretically found that the selectivity of the filter was also improved thanks to the oxide layer. The parameters for the designed device include the grating pitch of 450 nm, the grating height of 100 nm and the oxide-layer height of 200 nm. As for the fabricated filter, the spectral pass band corresponded to the blue color centered at 470 nm and the peak transmission was about 40%. Within the effective area of $3{\times}3mm^2$, the variation in the relative transmission efficiency and in the center wavelength was less than 10% and 2 nm respectively. Finally, the influence of the angle of the incident beam upon the transfer characteristics of the device was investigated in terms of the rate of the relative transmission efficiency, which was found to be equivalent to 1.5%/degree.

• Solar Energy
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• v.12 no.3
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• pp.10-20
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• 1992

In this experiment, photochemical reaction has been applied to destroy TCE in water phase. The main target of this work is to investigate the technical feasibility of large scale of solar detoxification reactor for water treatment. The results have revealed that solar detoxification utilizing photon energy from the sun is the most attractive process to decompose organic toxins in water phase at room temperature. The detailed results from this work are as follows; (1) The highest conversion ratio of TCE was obtained by using $TiO_2$, annatase as a photocatalyst among $TiO_2$ anatase, $TiO_2$ rutile and $V_2O_5$ under the same experimental condition. The anatase crystal structure was confirmed with XRD analysis, and its surface area was 7.748 $m^2/g$ from the BET-$N_2$ measurement (2) 0.1 wt% of $TiO_2$ anatase has been adopted as optimal quantity for batch slurry reactor at this experimental conditions. (3) The effect of hydrogen peroxide on the conversion of TCE was investigated. Its optimal quantity was 0.06 vol. % under this experimental conditions. (4) The effect of oxygen on the conversion of TCE also was studied by controlling the head space in photoreactor. Results indicated that sufficient amount of oxygen should be supplied to accomplish the highest conversion rate of TCE in water phase.

• Journal of Life Science
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• v.23 no.3
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• pp.406-414
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• 2013

The influence of a gradual increase in salinity on the diversity of aquatic bacterial in rivers was demonstrated. The denaturing gradient gel electrophoresis (DGGE) was used to analyze the bacterial community shift downstream in the Hyeongsan River until it joins the open ocean. Four water samples were taken from the river showing the salinity gradients of 0.02%, 1.48%, 2.63%, and 3.62%. The samples were collected from four arbitrary stations in 2.91 km intervals on average, and a DGGE analysis was performed. Based on the results of this analysis, phylogenetic similarity identification, tree analysis, and a comparison of each station were performed. The results strongly suggested that the response of the bacterial community response was concomitant to gradual changes in salinity, which implies that salt concentration is a major factor in shifting the microbiota in aquatic habitats. The results also imply a huge diversity in a relatively small area upstream from the river mouth, compared to that in open oceans or coastal regions. Therefore, areas downstream towards a river mouth or delta are could be good starting points in the search for new bacterial species and strains ("biotypes").

• Journal of the Korean institute of surface engineering
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• v.53 no.4
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• pp.131-137
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• 2020

A series of Dy³⁺, Sm³⁺, and Dy³⁺/Sm³⁺ doped Gd₂WO₆ phosphors were synthesized by the conventional solid-state reaction. The X-ray diffraction patterns revealed that all of the diffraction peaks could be attributed to the monoclinic Gd₂WO₆ crystal structure, irrespective of the type and the concentration of activator ions. The photoluminescence (PL) excitation spectra of Dy³⁺-doped Gd₂WO₆ phosphors contained an intense charge transfer band centered at 302 nm in the range of 240-340 nm and two weak peaks at 351 and 386 nm. Under an excitation wavelength of 302 nm, the PL emission spectra consisted of two strong blue and yellow bands centered at 482 nm and 577 nm. The PL emission spectra of the Sm³⁺-doped Gd₂WO₆ phosphors had a series of three peaks centered at 568 nm, 613 nm, and 649 nm, corresponding to the ⁶G_5/2 → ⁶H_5/2, ⁶G_5/2 → ⁶H_9/2, and ⁶G_5/2 → ⁶H_11/2 transitions of Sm³⁺, respectively. The PL emission spectra of the Dy³⁺- and Sm³⁺-codoped Gd₂WO₆ phosphors showed the blue and yellow emission lines originating from the ⁴F_9/2 → ⁶H_15/2 and ⁴F_9/2 → ⁴H_13/2 transitions of Dy³⁺ and reddish-orange and red emission bands due to the ⁴G_5/2 → ⁶H_7/2 and ⁴G_5/2 → ⁶H_9/2 transitions of Sm³⁺. As the concentration of Sm³⁺ increased from 1 to 15 mol%, the intensities of two PL spectra emitted by the Dy³⁺ ions gradually decreased, while those of the three emission bands due to the Sm³⁺ ions slowly increased, thus producing the color change from white to orange. The CIE color coordinates of Gd₂WO₆:5 mol% Dy³⁺, 1 mol% Sm³⁺ phosphors were (0.406, 0.407), which was located in the warm white light region.

• Journal of the Korean Geophysical Society
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• v.3 no.2
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• pp.77-90
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• 2000

Five electrical resistivity dipole-dipole and two seismic reflection surveys were performed in the southeastern margin of the Yongdong basin to delineate the shallow basin architecture. To investigate the intra-basin structure, twenty four resistivity sounding points and three dipole-dipole lines were selected especially in the vicinity of volcanic masses. The basin-fault boundaries are identified in electrical dipole-dipole resistivity section as high resistivity-contrast of approximately $1,500\;{\Omega}{\cdot}m$, characterized as a band of high standard-deviation. They are also effectively clarified in the seismic reflection data: amplitude and continuity contrasts in the common shot gather, first-arrival profiles, complex attribute plots. The intra-basin resistivity structures are constructed by interpolating vertical electrical sounding data and dipole-dipole profiles. The high-resistivity anomalies most likely originate from the northsouth-trending and northeast-dipping volcanic masses, which are to be further quantitatively investigated with geomagnetic and magnetotelluric surveys.

• Journal of the Korean earth science society
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• v.37 no.6
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• pp.332-345
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• 2016

The columnar joints in Goheung are developed in three places of Yuju-san area, Palyeong-san and Yongbawi area. Vertical and fan-shaped columnar joints which have maximum width 100 m and maximum heigh 50 m are developed in the Yuju-san area Columnar joints are developed next to the road near the the Yuju-san and along the coast of Jijuk-do. Thick columnar joints of maximum width 1m are developed in the Paryeong-san area. Horizontal columnar joints of maximum width 50 cm at length of polygon side are developed on dyke in the Yongbawi area. The columnar joints show high rate of rectangles and pentagons in the number of polygons. The length of polygon side of columnar joints in study area ranges from 10 to 100 cm, and 20 cm among the range appears in high frequency. Columnar joints are developed vertically to the ground from the cooling surface in Yuju-san and Palyeong-san area. Columnar joints in Yongbawi area are developed vertically to the contact of country rocks. As a result, the columnar joints began cooling from the country rock contact. And columnar joints are developed vertically to contact surface. The rocks in columnar joints is rhyolitic welded tuff in Yuju-san and Palyeong-san area, dacite in Yongbawi area. In the acid volcanic rocks flow structure well developed. The white phenocryst mineral about 2 mm size by eye, is usually feldspar, and includes some quartz. The rate of $SiO_2$ is 70wt.% or more. It is the last stage of differentiation to calc-alkaline series. The columnar joints of the Yuju-san area are expected to be distributed along a band that extends to about 1km east of the stone pit.