• Title/Summary/Keyword: Str

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An Improved PFC & Low Noise Power Supply using Quasi-Resonant Mode Hybrid IC of STR-G9600 (의사공진형 Hybrid IC STR-G9600을 이용한 저 노이즈 역률 개선형 전원 장치)

  • Lee Myung Jun;Ahn Jun Young;Shin Ho Jun;Bae Jun Sung
    • Proceedings of the KIPE Conference
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    • 2002.07a
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    • pp.233-236
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    • 2002
  • The solution for PFC(Power Factor Correction), as a regulation in energy Policy, is becoming a hot Issue in every country because of the shortage of electrical energy. Therefore, a new improved idea for PFC problem has been introduced in this study. A lot of merits, effective cost by simple circuit, reduced PCB size, lighter than reactor in the view of weight, lower level of screen noise by leakage inductance in CTV applications, have been stated by comparing to the earlier method of using a Reactor. All test results in this statement were done by using a power device of STR-G9600 series based on the real load condition of color television. furthermore, the study shows that the test results also meets the IEC-1000-3-2 class D, which regulates the PFC when input power of a set is more than 75watts. More improved PFC in other applications hopes to be implemented by using the proposed method.

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Synthesis and Anticonvulsant Activities of N-Cbz-${\alpha}$-aminoglutarimidooxy Carboxylate Derivatives

  • Byun, Ae-Sun;Choi, Jong-Won;Moon, Kyung-Ho;Lee, Chung-Gyu;Park, Min-Soo
    • Archives of Pharmacal Research
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    • v.29 no.6
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    • pp.459-463
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    • 2006
  • Previous studies on the anticonvulsant activity of $N-Cbz-{\alpha}-aminoglutarmides$ have shown that the derivatives of $N-Cbz-{\alpha}-amino-N-alkoxy$ glutarimide have significant anticonvulsant activity. In addition, their anticonvulsant activities are dependent on the presence of N-alkoxy groups. Based on these results, a series of $N-Cbz-{\alpha}-amino-glutarimidooxy$ carboxylates derivatives (3a-e) were synthesized in moderate yield using a known synthetic procedure. Their anticonvulsant activities were evaluated using the maximal electroshock seizure (MES) test, the pentylene tetrazole induced seizure (PTZ) test, and the strychinine (Str) threshold test with the ultimate aim of developing more active anticonvulsants. None of the compounds (3a-e) tested showed anticonvulsant activity in the MES and PTZ test. However, all the compounds tested exhibited significant anticonvulsant activity in the Str. test. The most active compound in the Str. test was the methyl ester of $N-Cbz-{\alpha}-amino-glutarimidooxy$ acetic acid 3a $(ED_{50}\;=\;42.9\;mg/kg)$.

Shikimate Metabolic Pathway Engineering in Corynebacterium glutamicum

  • Park, Eunhwi;Kim, Hye-Jin;Seo, Seung-Yeul;Lee, Han-Na;Choi, Si-Sun;Lee, Sang Joung;Kim, Eung-Soo
    • Journal of Microbiology and Biotechnology
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    • v.31 no.9
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    • pp.1305-1310
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    • 2021
  • Shikimate is a key high-demand metabolite for synthesizing valuable antiviral drugs, such as the anti-influenza drug, oseltamivir (Tamiflu). Microbial-based strategies for shikimate production have been developed to overcome the unstable and expensive supply of shikimate derived from traditional plant extraction processes. In this study, a microbial cell factory using Corynebacterium glutamicum was designed to overproduce shikimate in a fed-batch culture system. First, the shikimate kinase gene (aroK) responsible for converting shikimate to the next step was disrupted to facilitate the accumulation of shikimate. Several genes encoding the shikimate bypass route, such as dehydroshikimate dehydratase (QsuB), pyruvate kinase (Pyk1), and quinate/shikimate dehydrogenase (QsuD), were disrupted sequentially. An artificial operon containing several shikimate pathway genes, including aroE, aroB, aroF, and aroG were overexpressed to maximize the glucose uptake and intermediate flux. The rationally designed shikimate-overproducing C. glutamicum strain grown in an optimized medium produced approximately 37.3 g/l of shikimate in 7-L fed-batch fermentation. Overall, rational cell factory design and culture process optimization for the microbial-based production of shikimate will play a key role in complementing traditional plant-derived shikimate production processes.

Mode of Action of Streptomycin Resistance in the Citrus Canker Pathogen (Xanthomonas smithii subsp. citri) in Jeju Island

  • Hyun, Jae-Wook;Kim, Hyo-Jung;Yi, Pyoung-Ho;Hwang, Rok-Yeon;Park, Eun-Woo
    • The Plant Pathology Journal
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    • v.28 no.2
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    • pp.207-211
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    • 2012
  • It has been known that streptomycin resistance in bacteria can occur as a results of chromosomal mutation or through gene acquisition or both. Chromosomal mutations for resistances are point mutations in the rpsL gene, which alter ribosomal protein S12. Acquired resistance has occurred when an $Sm^R$ plasmid carrying transposon Tn5393 with tandem strA-strB gene is transferred by conjugation. A total of 686 isolates of Xanthomonas smithii subsp. citri causal agent of citrus canker disease were collected from 26 citrus orchards in Jeju Island in 2003 and 2004 seasons. Forty-nine of 111 isolates from streptomycin non-sprayed orchards in 2003 season were resistant to streptomycin. Of 107 isolates from orchards sprayed one time with streptomycin, 58 isolates were resistant, and 166 of 221 isolates from orchards sprayed two times with streptomycin were resistant. In 12 orchards sprayed three or more times with streptomycin, 219 of 247 isolates were resistant to streptomycin. Twenty-five isolates of X. smithii subsp. citri were surveyed to identify the mechanisms of streptomycin resistance in this study. Twenty-one of these 25 isolates were resistant to streptomycin, and it was proven by PCR assay that 18 of the 21 streptomycin resistant isolates have the strB gene. In sixteen of the 21 streptomycin resistant isolates, it was occurred a point mutation altered codon lysine (AAG)-41 of rpsL gene to arginine (AGG). The streptomycin-sensitive isolates easily acquired the resistance by mixed culture with resistant isolates. The strB gene was amplified from the isolates that acquired the resistance by mixed culture, and one isolate of them was also point-mutated in codon 41 of rpsL gene to be resistant. In this study, most of the streptomycin-resistant isolates of X. smithii sub sp. citri in Jeju island expressed the resistance by both chromosomal point mutation and gene acquisition, and the resistance was easily acquired through conjugation by culture mixed with streptomycin resistant and sensitive strains.

Growth Inhibition of Enteropathogenic Escherichia coli $A_2$and Escherichia coli $G_7$ by the Organic Acid Producing Bacteria (유기산 생성균에 의한 병원성 Escherichia Coli $A_2$와 Escherichia Coli $G_7$의 생육억제)

  • 백영진;배형석
    • Microbiology and Biotechnology Letters
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    • v.16 no.2
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    • pp.111-118
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    • 1988
  • The growth inhibition of enteropathogenic Escheriohia coli $A_2$and Escherichia coli G$_7$, causing the diarrhea in piglets, by the organic acid producing bacteria was studied in vitro. The metabolites of the organic acid bacteria, such as lactic acid, acetic acid inhibited the growth of E. coli $A_2$and E. coli G$_7$ in BL medium. The more the organic acid producing bacteria have ability to produce the organic acids, the higher these bacteria excelled the inhibitory efficacy against enteropathogenic E. coli. Among the strains examined, Lactobacillus casei Y and Streptococcus faecium C showed relatively strong growth inhibition against enteropathogenic E. coli.. When the organic acid producing bacteria and the enteropathogenic E. coli were incubated simultaneously in BL medium, bacteriostasis of E. coli was observed when the pH of BL culture was lowered to 5.0, and bacteriocidal effect was observed when the pH became Bess than 4.5, E. coli. $A_2$was more resistant to the organic acid bacteria than E. coli G$_7$.

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Seismic Performance-based Design using Computational Platform for Structural Design of Complex-shaped Tall Building (전산플랫폼을 이용한 비정형 초고층 건축물 성능기반 내진설계기술의 실무적용)

  • Lee, Dong-Hun;Cho, Chang-Hee;Youn, Wu-Seok;Kang, Dae-Eon;Kim, Taejin;Kim, Jong-Ho
    • Journal of the Computational Structural Engineering Institute of Korea
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    • v.26 no.1
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    • pp.59-67
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    • 2013
  • Complex-shaped tall building causes many structural challenges due to its structural characteristics regarding inclined members and complexed shape. This paper is aimed at development of design process using computational-platform which is effective design tool for responding frequent design changes, particularly as to overseas projects. StrAuto, a parametric structural modeling and optimizing system, provides the optimized alternatives according to design intent and realize a swift process converting a series of structural information necessary to nonlinear analytical models. The application of the process was to a 45-story hotel building in Ulanbator, Mongolia adopting shear wall and special moment frame with outrigger systems. To investigate the safety of lateral force resisting system against maximum considered earthquake(MCE), nonlinear response history analysis was conducted using StrAuto.

적응 제어의 소개

  • 최종호
    • 전기의세계
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    • v.30 no.12
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    • pp.770-772
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    • 1981
  • 적응 제어의 이론을 설명하기 위하여 STR 방법과 MARC방법에 대하여 각각 하나의 방법을 소개하였고 이들을 사용하는데 고려하여야 할 점들을 기술하였다.

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