• Proceedings of the KIEE Conference
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• 2005.07c
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• pp.2306-2308
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• 2005

전자파 산란을 측정하는 능동 원격 탐지 시스템은 전자파를 표적에 가한 후, 그 표적으로부터 돌아오는 전자파의 양으로 표적에 대한 정보를 얻는 시스템이다. 본 논문에서는 회로망 분석기(HP8510C)를 이용하여 표적으로부터 돌아오는 전자파의 양을 측정하여 시간 영역에서의 해석을 통하여 K-band에서의 레이더 단면적(RCS)을 측정하는 방법에 대해 서술한다.

• Bulletin of the Korean Chemical Society
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• v.16 no.10
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• pp.929-933
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• 1995

The electronic band structure and electrical properties of KMo4O6 containing chains of condensed molybdenum octahedra are analyzed by means of the extended Hu&ckel tight-binding method. KMo4O6 has partially filled bands of 1D as well as 3D character. They also exhibit the anisotropic band dispersions with bandwidths much larger along the c* axis than along the directions perpendicular to it. Thus, conduction electrons are essentially delocalized along the c* direction (i.e., the chain of condensed molybdenum octahedra) in the solid. The 1D band of two partially filled d-block bands leads to Fermi surface nesting with the wave vector q=0.3c*. The CDW instability due to this nesting is expected to cause the phase transition associated with the resistivity anomaly at low temperature. The characteristics of metallic behavior in the crystallographic ab plane are explained on the basis of the unnested 2D Fermi surfaces.

• The Transactions of the Korean Institute of Electrical Engineers C
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• v.55 no.4
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• pp.172-177
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• 2006

During normal machine operation, partial discharge(PD) tests were performed with partial discharge analyzer(PDA) in two hydrogenerators. Six cable couplers were installed in circuit ring bus and endwinding of three phases. PDA showed that the normalized quantity number(NQN) and the partial discharge magnitude$(Q_m)$ were very low in hydrogenerator #1 and #2, respectively. The trend analyses of NQN and $Q_m$ value are available for monitoring of the insulation condition in hydrogenerator stator windings. The insulation condition of stator winding can be assessed. Discharge at conductor surface was discovered in B phase(C2 coupler) of hydrogenerator #1. Internal discharges were generated in A and C phases(C2 coupler) of hydrogenerator #1 and in A, Band C phases(C1 and C2 couplers) of hydrogenerator #2. Slot discharges occurred in A, Band C phases(C1 coupler) of hydrogenerator #1. The stator windings of two hydrogenerators were in good condition.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.20 no.4
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• pp.366-374
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• 2009

ITU has considered the 3,400$\sim$4,200 MHz band, which is allocated worldwide on a primary basis to the FSS, as a candidate band for future development of IMT system. In this band, this paper presents the results of the sharing studies performed between FSS and IMT systems through the theoretical and simulation analysis on the interference from multiple IMT base stations into a receiving FSS earth station considering the interference mitigation techniques such as antenna tilt angle and 3 sectors on the IMT base station. By using the long-term and short-term interference threshold, the coordination areas for the FSS earth station are provided to share frequency in 3,400$\sim$4,200 MHz band between FSS earth station and multiple IMT base stations in future.

• The Korean Journal of Mycology
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• v.26 no.4 s.87
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• pp.551-561
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• 1998

Plasma membrane from the fungal cells (Aspergillus phoenicis, Rhizopus acidus, Candida albicans) treated with sodium benzoate (S.B), potassium sorbate (P.S) and calcium propionate (C.P) during the cultivation were separated. The contents and patterns of plasma membrane proteins compared with those of the control. The growth of A. phoenicis was decreased by the average 64.0% in the S.B treatment. That of R. acidus was inhibited by the average 69.0% in the P.S treatment. Also, That of C. albicans was showed the deminution of the average 59.5% in the S.B treatment. The contents of protein involved in the plasma membrane of the each fungal cells were inhibited the average 41.0%, 41.7% and 59.5% in the S.B treatment, respectively. In case of A. phoenicis, the changes in the protein pattern involved in the plasma membraneshowed the aspect similar to the control on the 1st day and 2nd day of cultivation in the treatment group, but $116\;KD{\sim}97\;KD$ band almost disappeared in the 5th day of cultivation, and $45\;KD{\sim}29\;KD$ band was uncleared through the cultivation. In S.B treatment group R. acidus was showed the loss of $116\;KD{\sim}97\;KD$ band from the middle stage of cultivation and P.S, and C.P treatment group were started the loss at the early stage and completely lost at the 36 hours of cultivation. In C. albicans, $116\;KD{\sim}97\;KD$ band were started the loss at the early stage to compare with the control and $66\;KD{\sim}45\;KD$ band were dimmed at the 96 hours of cultivation. Especially, the C.P treatment group were perfectly lost at the 96 hours of cultivation.

• Journal of Life Science
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• v.12 no.1
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• pp.77-86
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• 2002

Chitin, a $\beta$-1,4 polymer of N-acetyl-D-glucosamine, is one of the most abundant organic compounds in nature. Chitinase (EC 3.2.1.14) is an enzyme that degrades chitin to chito-oligosaccharides, diacetyl rhitobiose and N-acetyl-D-glucosamine. An extracellular chitinase-producing bacterial strain was isolated from soil and named to as Bacillus subtilis JK-56. Optimum culture condition of B. subtilis JK-56 for the production of chitinase was 1% chitin, 0.5% polypepton, 0.1% KCl, 0.05% MnS $O_4$.4$H_2O$, 37$^{\circ}C$, initial pH 7.0 and 40 hour culture time. When B. subtilis JK-56 was grown in the optimum medium, one major active band and two minor active bands were detected by native-PAGE and active staining of the gel. Among them, the major band was purified from the culture supernatant by 70% ammonium sulfate precipitation and native-PAGE with BIO-RAD Model 491 Prep-Cell and named as Chi-56A. Its molecular weight was estimated to be 53kDa monomer and the isoelectric point (pI) was pH 4.3. The pH and temperature for the optimum activity of Chi-56A were pH 6.0 and $65^{\circ}C$, respectively. Chi-56A was stable up to $65^{\circ}C$ and in alkaline region. Its $K_{m}$ value for colloidal chitin was 17.33g/L. HPLC analysis of the reaction products confirmed that Chi-56A was an exo type chitinase.e.

• Korean Journal of Materials Research
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• v.19 no.10
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• pp.522-526
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• 2009

Graphene has been effectively synthesized on Ni/SiO$_2$/Si substrates with CH$_4$ (1 SCCM) diluted in Ar/H$_2$(10%) (99 SCCM) by using an inductively-coupled plasma-enhanced chemical vapor deposition. Graphene was formed on the entire surface of the 500 nm thick Ni substrate even at 700 $^{\circ}C$, although CH$_4$ and Ar/H$_2$ gas were supplied under plasma of 600 W for 1 second. The Raman spectrum showed typical graphene features with D, G, and 2D peaks at 1356, 1584, and 2710 cm$^{-1}$, respectively. With increase of growth temperature to 900 $^{\circ}C$, the ratios of the D band intensity to the G band intensity and the 2D band intensity to the G band intensity were increased and decreased, respectively. The results were strongly correlated to a rougher and coarser Ni surface due to the enhanced recrystallization process at higher temperatures. In contrast, highquality graphene was synthesized at 1000 $^{\circ}C$ on smooth and large Ni grains, which were formed by decreasing Ni deposition thickness to 300 nm.

• Proceedings of the KSRS Conference
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• v.2
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• pp.930-933
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• 2006

A new algorithm for satellite microwave rainfall retrievals over the land of Taiwan using TMI (TRMM Microwave Imager) data on board TRMM (Tropical Rainfall Measuring Mission) satellite is described in this study. The scattering index method (Grody, 1991) was accepted to develop a rainfall estimation algorithm and the measurements from Automatic Rainfall and Meteorological Telemetry System (ARMTS) were employed to evaluate the satellite rainfall retrievals. Based on the standard products of 2A25 derived from TRMM/PR data, the rainfall areas over Taiwan were divided into convective rainfall area and stratiform rainfall areas with/without bright band. The results of rainfall estimation from the division of rain type are compared with those without the division of rain type. It is shown that the mean rainfall difference for the convective rain type is reduced from -6.2mm/hr to 1.7mm/hr and for the stratiform rain type with bright band is decreased from 10.7 mm/hr to 2.1mm/hr. But it seems not significant improvement for the stratiform rain type without bright band.

• The Journal of the Korea institute of electronic communication sciences
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• v.3 no.4
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• pp.289-294
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• 2008

Affordable traffic capacity of each node in networks is expected to reach in Tb/s range in proportion to the rapid growth of Internet users. To transmit more than Tb/s per fiber pair, WDM should be used as well as existing TDM. To increase the capacity of transmission in WDM networks, there are two ways, increasing channel speed or channel quantity. To increase the channel quantity, there are two ways, narrow spacing or expanding transmission bandwidth. To expand bandwidth, ultra-broadband optical amplifier technology is necessary. In this paper, we introduce EDFA in effect at C/L band, FRA, and some optical amplifiers in effect at S band, and analyze the development trend of various amplification technologies.

• Proceedings of the KSRS Conference
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• 1999.11a
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• pp.267-270
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• 1999

Use of coherence data from operational satellite based SAR sensors has been experimented both on C and L band to identify landcover in tropics. While coherence data proved useful to improve accuracy in landcover identification, such data are not readily available. On the other hand, integrated use of backcatter data by multiple satellites is readily feasible. The very question to be asked is whether integration of backscatter data on multiple bands (e.g. C and L band) is either inferior or superior to use of coherence data. We therefore still do not have a solid clue to answer to the very question. The aim of this study is to evaluate the performance of "integrated use" of backscatter data on C and L band (by ERS and JERS respectively) to identify landcover, vis-a-vis the same by combination of backscatter and coherence data by single satellite. The study was carried out for an area in the southern part of the Sumatra Island, Indonesia. The area has been intensively converted from natural forest into plantation. Five categories of landcover exist in this study area. By ERS-1, only 2 or 3 classes may be identified with the backscatter data alone, while adding the coherence data could delineate 4 classes. By JERS-1, only 3 to 4 classes may be identified with the backscatter data alone, while 4 classes could be clearly delineated by adding the coherence data. By integrating backscatter data on two bands, 4 to 5 classes may be identified. It represents the best results among cases examined. The outcome of the study suggests that integrated use of backscatter data on two bands by ERS and JERS is as powerful as use of backscatter and coherence data on single band by one of these satellite.