• Proceedings of the KIPE Conference
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• 2013.07a
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• pp.536-537
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• 2013

전기로와 같은 고압, 대용량의 산업응용분야에서 전원 안정화를 목적으로 하는 변동부하에 의해 발생되는 정상분 및 역상분의 무효전력을 보상하기 위한 고성능의 STATCOM의 개발이 요구되었다. 본 논문에서는 POSCO ICT에서 개발한 22.9kV 5MVA STATCOM(static synchronous compensator)에 대해 기술하였다. 개발된 STATCOM은 다단 멀티레벨 컨버터(Cascaded Multilevel Converter) 방식으로 Delta 구성하였으며, 각상당 12개의 H-Bridge Inverter가 직렬로 구성되어 25 레벨의 전압을 출력한다.

• Bulletin of the Korean Chemical Society
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• v.20 no.1
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• pp.65-68
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• 1999

Novel mononuclear group 13 metal complexes with the formula (R2M){NC5H4C(CH3)NNC(S)NH(C6H5)} (M=Al, R=iC4H9 (1); M=Ga, R=iC4H9 (2); M=Al, R=CH2SiMe3 (3); M=Ga, R=CH2SiMe3 (4)) result when 2-acetyl pyridine 4-phenyl-thiosemicarbazone ligand is mixed with trialkyl aluminum or trialkylgallium. These compounds 1-4 are characterized by microanalysis, NMR (1H, 13C) spectroscopy, mass spectra, and singlecrystal X-ray diffraction. X-ray single-crystal diffraction analysis reveals that 1 is mononuclear metal compound with coordination number of 5 and N, N, S-coordination mode.

• Communications of the Korean Mathematical Society
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• v.9 no.2
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• pp.261-264
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• 1994

Throughout this paper, all rings are assumed to be commutative with identity. By a local ring (R, m), we mean a Noetherian ring R which has the unique maximal ideal m. By dim(R) we always mean the Krull dimension of R. Let I be an ideal in a ring R and t an indeterminate over R. Then the Rees algebra R[It] is defined to be(omitted)

• Journal of Sericultural and Entomological Science
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• v.9
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• pp.43-47
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• 1969

This experiment was carried out to investigate the effect of gamma ray on the eggs of later stage in late fall rearing season. The results are summarized as follows: 1. The duration of larval stage was simmilar to that of control in any dose. The silkworm growth was uniform in does of 4,000 gamma ray, but in does of 8,000r 16000r was irregular. There were not malformed silkworms but many small silkworm. 2. Mortality of silkworms was very high 8,000r and over; virus diseases of 87.6 per cent, flacherie of 5.9 per cent and complication of 6.5 per cent. 3. The more the dose of gamma ray became, the lighter the weight full grown silkworm and matured silkworm became. 4. The uniformness of cocoons was registered in dose of 2,000r and the cocoons were irregular or small in dose of 16,000r

• Bulletin of the Korean Chemical Society
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• v.10 no.2
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• pp.191-196
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• 1989

We obtained the new complexes, $Fe{\eta}^4-R,R'-TPSCp](CO)_3$(R,R'-TPSCp = 1,1-disubstituted 2,3,4,5-Tetraphenyl-1-Silacyclopenta-2,4-diene; R = Ph, R' = Cl, R = R' = Cl) from the reaction of the corresponding R,R'-TPSCp with ironpentacarbonyl under reflux in toluene. Also, the analogous complexes with R = R' = Me and R = Me, R' = Cl were obtained in an identical manner. We have determined the crystal structure of $Fe[Ph(Cl)-TPSCp](CO_)3$ by using Mo ka, ${\lambda}$ = 0.71069${\AA}$, where the unit cell was found to be monoclinic with a = 9.042 (6)${\AA}$, b = 19.870 (9)${\AA}$, c = 17.426 (9)${\AA}$ and ${\beta}$ = 96.28(4)$^{\circ}$. The butadiene moiety of TPSCp ring is planar and the dihedral angle of the butadiene plane and C4-Si-C25 plane was opened up to 41.8$^{\circ}$. The C-C distances in the butadiene moiety were found to be 1.4346, 1.462, and 1.440 ${\AA}$, respectively. It may be said that the four ${\pi}$-electrons are delocalized over the four carbons in five membered ring through coordination with ironcarbonyl. In this complex Fe is either in distorted tetrahedron environment with the centroid of the four C-atom butadiene moiety and three carbons of the three carbonyls or in distorted square-pyramidal environment with two midpoints of double bonds of the butadiene moiety and two carbons of carbonyl defining the base of the pyramid and the carbon of remaining carbonyl the apex.

• Smart Media Journal
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• v.11 no.8
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• pp.9-20
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• 2022

With the rise of the metaverse industry worldwide, relevant national strategies and nurturing systems have been prepared in Korea. As the complexity of policies increases, the importance of establishing data-based policymkaing is growing, and studies diagnosing national R&D trends in the metaverse field are still lacking. Therefore, this paper collected NTIS national R&D information for 9,651 R&D projects promoted from 2002 to 2020. And this study looked at the current status and identified major topics based on the topic modeling, and considered time-series changes in the topics. Eleven major topics of R&D tasks in the metaverse field were derived, hot topics were service/content/platform development and medical/surgical fields of application fields, and cold topics were urban/environment/spatial information fields. Strategic R&D Management, metaverse-related laws, and institutional studies were proposed as policy directions.

• Clinical and Experimental Pediatrics
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• v.46 no.6
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• pp.548-553
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• 2003

Purpose : Matrix metalloproteinase(MMP)-9 is known to breakdown the blood-brain barrier by degrading the extracellular matrix of the subendothelial basement membrane in meningitis. Tissue inhibitor of metalloproteinase(TIMP)-1, a known inhibitor of MMP-9, has been postulated to inhibit the proteolytic activity of MMP-9 by bindng to MMP-9, but their interaction has not been fully understood yet. So far, there have been some reports on the relationship of MMP-9 and TIMP-1 in bacterial meningitis, but few reports in viral meningitis. Furthermore, there has been no report on this in Korea. We investigated the concentrations of MMP-9 and TIMP-1 in cerebrospinal fluid (CSF) and serum of patients with viral meningitis and control subjects, and evaluated their relationship with other clinical parameters of meningitis. Methods : CSF and blood were obtained from 25 subjects with viral meningitis and 14 control subjects. After centrifugation, supernatants were stored at $-20^{\circ}C$ and we assayed concentrations of MMP-9 and TIMP-1 by the sandwich ELISA method. Results : Concentrations of CSF MMP-9 and TIMP-1 were significantly elevated in patients with viral meningitis, when compared with those in control subjects. Their serum levels showed no differences between the two groups. MMP-9 levels were closely correlated with TIMP-1 levels in the CSF($r_s=0.42$, P<0.05). CSF MMP-9/TIMP-1 ratios were significantly higher in patients with viral meningitis than those in the control subjects(P<0.05). Both CSF MMP-9 and TIMP-1 levels positively correlated with CSF total leukocyte counts($r_s=0.43$, P<0.05, $r_s=0.48$, P<0.05). TIMP-1 levels positively correlated with total protein concentrations in the CSF($r_s=0.43$, P<0.05). Conclusion : MMP-9 and TIMP-1 may play an important role in the breakdown and maintenance of BBB in viral meningitis, respectively.

• Proceedings of the Korean Operations and Management Science Society Conference
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• 1988.10a
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• pp.9-9
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• 1988

• Bulletin of the Korean Chemical Society
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• v.22 no.9
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• pp.1033-1036
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• 2001

• YAKHAK HOEJI
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• v.39 no.3
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• pp.268-275
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• 1995

A novel polyacetylene was isolated from Cirsium spp., as well as five known ones, and its chemical structure was determined as heptadeca-1-en-11.13-diyne-8R, 9S, 10R-triol(1) on the basis of spectral data and chemical reactions. $^{1}$H-and $^{13}$C-NMR data of these polyacetylenes were completely assigned by the appfication of 2D-NMR techniques.