• 제목/요약/키워드: Pi

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폴리이미드 박막의 공간전하현상 (Space Charge Phenomena in Polyimide Films)

  • 윤주호;최용성;이경섭
    • 한국전기전자재료학회:학술대회논문집
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    • 한국전기전자재료학회 2007년도 추계학술대회 논문집
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    • pp.311-312
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    • 2007
  • Polyimide is widely used as a high-temperature insulating material. Space charge distributions in polyimide (PI) films strongly depend upon electric field, temperature, water content and so on. We observed space charge distributions in PI films with various water contents. When a dc field was applied to as-received PI films or water-treated PI films, positive and negative homo space charges were observed near the respective electrodes at 333 K. In dried PI films, the homo space charges were much reduced, and positive and negative hetero space charges in the bulk were clearly observed. The space charge amounts in water-treated PI films were smaller than in as-received ones, while the current density in water-treated PI film was larger than that in as-received one by two or more orders of magnitude. These suggest not only that the charge injection from the electrode is enhanced by absorbed water but also that absorbed water makes carriers mobile. The decay of space charge was also faster in water-treated PI than in as-received or dried one. This also supports the enhancement of apparent mobilities of carriers in PI by absorbed water.

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SVC를 포함한 전력시스템의 안정도 향상을 위한 최적 퍼지-PI 제어기의 설계 (A Design of Optimal Fuzzy-PI Controller to Improve System Stability of Power System with Static VAR Compensator)

  • 김해재;주석민
    • 전기학회논문지P
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    • 제53권3호
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    • pp.122-128
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    • 2004
  • This paper presents a control approach for designing a fuzzy-PI controller for a synchronous generator excitation and SVC system. A combination of thyristor-controlled reactors and fixed capacitors(TCR-FC) type SVC is recognized as having the most flexible control and high speed response, which has been widely utilized in power systems, is considered and designed to improve the response of a synchronous generator, as well as controlling the system voltage. A Fuzzy-PI controller for SVC system was proposed in this paper. The PI gain parameters of the proposed Fuzzy-PI controller which is a special type of PI ones are self-tuned by fuzzy inference technique. It is natural that the fuzzy inference technique should be based on humans intuitions and empirical knowledge. Nonetheless, the conventional ones were not so. Therefore, In this paper, the fuzzy inference technique of PI gains using MMGM(Min Max Gravity Method) which is very similar to humans inference procedures, was presented and applied to the SVC system. The system dynamic responses are examined after applying all small disturbance condition.

폴리이미드 박막의 공간전하현상에 관한 연구 동향 (A Research Trend on High Density Polyethylene Electrical Strength)

  • 최근호;오창근;신현만;황종선;최용성;이경섭
    • 대한전기학회:학술대회논문집
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    • 대한전기학회 2007년도 제38회 하계학술대회
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    • pp.1984-1985
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    • 2007
  • Polyimide is widely used as a high-temperature insulating material. Space charge distributions in polyimide (PI) films strongly depend upon electric field, temperature, water content and so on. We observed space charge distributions in PI films with various water contents. When a dc field was applied to as-received PI films or water-treated PI films, positive and negative homo space charges were observed near the respective electrodes at 333 K. In dried PI films, the homo space charges were much reduced, and positive and negative hetero space charges in the bulk were clearly observed. The space charge amounts in water-treated PI films were smaller than in as-received ones, while the current density in water-treated PI film was larger than that in as-received one by two or more orders of magnitude. These suggest not only that the charge injection from the electrode is enhanced by absorbed water but also that absorbed water makes carriers mobile. The decay of space charge was also faster in water-treated PI than in as-received or dried one. This also supports the enhancement of apparent mobilities of carriers in PI by absorbed water.

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넙치에서 분리된 phosphoinositide 3-kinase γ 유전자의 클로닝 및 특성 연구 (Cloning and Characterization of Phosphoinositide 3-Kinase γ cDNA from Flounder (Paralichthys olivaceus))

  • 정태혁;윤주연;지근호;서용배;김영태
    • 생명과학회지
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    • 제24권4호
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    • pp.343-351
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    • 2014
  • Phosphoinositide 3-kinase (PI3K)는 항산화 제어반응, 심근세포 성장, 및 세포 내 특수반응 뿐만 아니라 세포분화, 생장, 운동, 식균 및 내항작용, 세포 골격유지에 관여하는 등 세포 신호체계에서 핵심 역할을 하는 효소이다. PI3K는 세 그룹으로 나누어지며 type I PI3K는 leukocyte에서 우선적으로 발현되고 G-proteins의 ${\beta}{\gamma}$ subunits에 의해서 활성화 된다. 본 연구에서는 넙치(Paralichthys olivaceus)의 $PI3K{\gamma}$를 암호화하는 cDNA를 클로닝하였다. 넙치의 $PI3K{\gamma}$는 1,341 bp 염기로 구성되는 한 개의 ORF를 가지며 이 단백질은 447 아미노산으로 구성되어있다. $PI3K{\gamma}$는 zebrafish의 $PI3K{\gamma}$와 89.6%, mouse와는 84.7%, Norway rat와는 84%, human의 $PI3K{\gamma}$와는 74.9%가 아미노산 상동성을 나타내었다. $PI3K{\gamma}$유전자의 대장균에서 발현을 위하여 pET-44a(+)-PI3K 재조합 DNA를 구축하여 대장균에서 발현시킨 결과 49 kDa의 재조합 단백질이 과발현 됨을 확인 할 수 있었다. His-tag affinity chromatography를 이용하여 $PI3K{\gamma}$단백질을 순순 분리하였으며 wortmannin을 이용하여 $PI3K{\gamma}$의 활성을 분석하였다.

국내분리 Aujeszky's disease virus의 실험적 감염 자돈에 대한 바이러스학적 연구 (Experimental infection of piglets with a field isolate of Aujeszky's disease virus in Korea: Pathogenecity, excretion, distribution and immunogenicity of virus)

  • 박정우;전무형;안수환
    • 대한수의학회지
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    • 제30권2호
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    • pp.177-186
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    • 1990
  • To investigate the etiology, pathogenicity and virological properties of NYJ-1-87 strain of Aujeszky's disease virus (ADV) that was isolated from the diseased piglet in Korea, the virus at $10^{6.0}TCID_{50}/0.1ml$ was inoculated intranasally and subcutaneously into 30 to 35 days-old piglets. Results obtained through the experiments were summarized as follows. 1. Ten of the infected piglets were clinically observed for 15 days. On the 2nd day post-inoculation(pi), the signs of pyrexia, anorexia and convulsion were noted. On the 4th to 7th days pi, nervous signs of incoordination and intermittent spasm were shown in the most of piglets, and one out of 5 piglets infected intranasally was died with severe nervous signs at the 7th day pi. The signs became relieved on the 8th day pi and all of remainder were completely recovered on the 13th to 14th days pi. 2. In hematological study, prominent decrease in the number of total leukocyte and lymphocyte was shown in the ADV-infected piglets on the 6th day pi. On the 8th day pi, the cell numbers were slightly increased and returned to normal level on the 10th day pi. 3. Viral excretion of the ADV-inoculated piglets was examined by swabbing of nasal and oral cavities, and rectal feces. During the periods of the 3rd to 11th days pi, the virus was excreted intermittently from nasal and oral cavities, and rectal feces. The nasal excretions were shown the highest virus concentration of $10^{5.2}TCID_{50}/0.1ml$ at the 5th day pi. 4. Recovery of the inoculated virus from various organs of the piglets that were died or experimentally slaughtered was attempted, and the virus was isolated from the tissues of brain and tonsil by the cultured cell-inoculation method. The highest recovery rate was noted in the tonsil. By indirect immunofluorescence antibody assay using ADV-monoclonal antibody, the viral antigens were detected in tissues of spleen and liver as well as brain and tonsil on the 7th to 9th days pi. The virus was not isolated from blood and the tissues of lung and kidney throughout the experiments. 5. Titers of virus neutralizing antibody in the piglets experimentally infected with ADV became increased after the 6th to 9th days pi in both of intranasal and subcutaneous inoculation showing the highest titers of 64 to 128 on the 29th day pi. When the antibody levels were measured by radial immunodiffusion enzyme assay, the reactive diameter was enlarged to be positive after the 4th to 6th days pi in both of intranasal and subcutaneous inoculation showing the largest diameter of 13 to 14mm on the 29th day pi.

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Chitosan이 함유된 보존제의 첨가가 돈육 Patty의 저장에 미치는 효과 (Effects of Preservative Containing Chitosan on the Shelf Life of Pork Patty)

  • 박나영;정은주;이신호
    • 한국식품영양과학회지
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    • 제42권9호
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    • pp.1446-1451
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    • 2013
  • Chitosan 함유 보존제를 각각 1%, 3%, 5% 첨가하여 제조한 patty의 관능검사 결과, 맛과 종합적 기호도의 경우 PI-1 처리구, PII-1 처리구가 대조구보다 유의적으로 높은 값을 나타내었다. DPPH 라디칼 소거능은 대조구, 1% PI-1 처리구, 1% PII-1 처리구가 각각 13.54%, 21.78%, 14.07%로 PI-1 처리구가 대조구보다 유의적으로 높았다. 총균수는 저장 10일째 PI-1 처리구는 $10^4$ CFU/g으로 대조구보다 약 1 log cycle 낮았으며, 대장균군수는 저장 10일째 PI-1 처리구가 2.98 log CFU/g으로 가장 낮았으며, 다음은 PII-1 처리구 낮았다. 가열 감량은 PI-1 처리구와 PII-1 처리구가 대조구보다 낮았고, 저장기간이 경과할수록 유의적으로 감소하는 경향을 나타내었다. 보수력은 PI-1 처리구가 65.84%로 가장 높았으며, 저장기간 동안 대조구보다 높은 값을 유지하였다. 휘발성 염기태 질소는 대조구가 5일째까지, 보존제 처리구는 10일째까지 가식권의 한계치 이하로 나타났다. L 값은 저장기간 동안 뚜렷한 변화는 나타나지 않았고 a 값은 저장 5일째부터 급격히 낮아졌으며, b 값은 저장기간 동안 서서히 증가하는 경향을 나타내었다.

인체상피조직 및 타액내 해독효소로서의 glutathione transferase Pi (Pi Class of Glutathione Transferase is the Major Form of Detoxifying Enzyme in the Human Epithelial Tissues and Saliva)

  • 박상철;곽상순;서희명;김옥경;정윤미;최경호;김우호
    • 한국환경성돌연변이발암원학회지
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    • 제11권2호
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    • pp.148-160
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    • 1991
  • 인체의 여리 조직을 대상으로하여 면연조직화학전방법을 통하여 glutathione transferase isoenzyme의 분포를 비교 분석하였다. 상피조직중의 GST-Pi의 다랑분포가 확인되었으며, 특히 외인성 화학물질에 노출되기 쉬운 피부, 유두, 신도 등의 과립층과 췌장, 담도, 타액선, 신세뇨관등의 배설관의 상피 또는 난소의 theca와 granulosa, 고환의 Leydig세포, 부신피 질의 zona reticularis 등의 steroid 생합성이 왕성한 부위에서 높은 GST-Pi 분포가 관찰되었다. 면역조직화학적 분석과 병행하여 Western blot 분석을 시행해본 결과 이러한 GST-Pi 분포가 인체유래 유각상피세포 중에서도 확인되었다. 그러나 K-ras 암유전자로 형질전환하여 암화능을 갖춘 인체상피세포주의 GST-Pi 발현은 유의한 차이를 보이지 않았다. 뿐만아니라 타액중에서도 GST-Pi가 다량 존재함이 Western blot 분석에 의하여 구명되었다. 이러한 결과는 GST-Pi가 인체조직 중 외인성독성물질에 노출되는 부위, 내인성 steroid 합성부위 및 배설능을 갖는 부위의 상피조직에 주로 존재하고 있음을 보여주고 있으며, 이러한 GST-Pi의 조직분포는 동효소가 인체의 해독기능에 주요한 역할을 하고 있음을 시사해주고 있다.

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PBT-6, a Novel PI3KC2γ Inhibitor in Rheumatoid Arthritis

  • Kim, Juyoung;Jung, Kyung Hee;Yoo, Jaeho;Park, Jung Hee;Yan, Hong Hua;Fang, Zhenghuan;Lim, Joo Han;Kwon, Seong-Ryul;Kim, Myung Ku;Park, Hyun-Ju;Hong, Soon-Sun
    • Biomolecules & Therapeutics
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    • 제28권2호
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    • pp.172-183
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    • 2020
  • Phosphoinositide 3-kinase (PI3K) is considered as a promising therapeutic target for rheumatoid arthritis (RA) because of its involvement in inflammatory processes. However, limited studies have reported the involvement of PI3KC2γ in RA, and the underlying mechanism remains largely unknown. Therefore, we investigated the role of PI3KC2γ as a novel therapeutic target for RA and the effect of its selective inhibitor, PBT-6. In this study, we observed that PI3KC2γ was markedly increased in the synovial fluid and tissue as well as the PBMCs of patients with RA. PBT-6, a novel PI3KC2γ inhibitor, decreased the cell growth of TNF-mediated synovial fibroblasts and LPS-mediated macrophages. Furthermore, PBT-6 inhibited the PI3KC2γ expression and PI3K/AKT signaling pathway in both synovial fibroblasts and macrophages. In addition, PBT-6 suppressed macrophage migration via CCL2 and osteoclastogenesis. In CIA mice, it significantly inhibited the progression and development of RA by decreasing arthritis scores and paw swelling. Three-dimensional micro-computed tomography confirmed that PBT-6 enhanced the joint structures in CIA mice. Taken together, our findings suggest that PI3KC2γ is a therapeutic target for RA, and PBT-6 could be developed as a novel PI3KC2γ inhibitor to target inflammatory diseases including RA.

Screening of the Dominant Rice Blast Resistance Genes with PCR-based SNP and CAPS Marker in Aromatic Rice Germplasm

  • Kim, Jeong-Soon;Ahn, Sang-Nag;Hong, Sung-Jun;Kwon, Jin-Hyeuk;Kim, Yeong-Ki;Jee, Hyeong-Jin;Shim, Chang-Ki
    • 한국작물학회지
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    • 제56권4호
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    • pp.329-341
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    • 2011
  • The objective of this study was to determine the genetic diversities of major rice blast resistance genes among 84 accessions of aromatic rice germplasm. Eighty four accessions were characterized by a dominant 11 set of PCR-based SNP and CAPS marker, which showed the broad spectrum resistance and closest linkage to seven major rice blast resistance (R) genes, Pia, Pib, Pii, Pi5 (Pi3), Pita (Pita-2), and Pi9 (t). The allele specific PCR markers assay genotype of SCAR and STS markers was applied to estimate the presence or absence of PCR amplicons detected with a pair of PCR markers. One indica accession, Basmati (IT211194), showed the positive amplicons of five major rice blast resistance genes, Pia, Pi5 (Pi3), Pib, Pi-ta (Pi-ta2), and Pik-5 (Pish). Among 48 accessions of the PCR amplicons detected with yca72 marker, only five accessions were identified to Pia gene on chromosome 11. The Pib gene was estimated with the NSb marker and was detected in 65 of 84 accessions. This study showed that nine of 84 accessions contained the Pii gene and owned Pi5 (Pi3) in 42 of 84 accessions by JJ817 and JJ113-T markers, which is coclosest with Pii on chromosome 9. Only six accessions were detected two alleles of the Pita or Pita-2 genes. Three of accessions were identified as the Pi9 (t) gene locus.

흐름 다중 심벌 검파를 사용한 트렐리스 부호화된 $\pi$/8 shift 8PSK-OFDM (Trellis-coded $\pi$/8 shift 8PSK-OFDM with Sliding Multiple Symbol Detection)

  • 안필승;김종일;김한종
    • 한국정보통신학회논문지
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    • 제6권4호
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    • pp.535-543
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    • 2002
  • 본 논문에서는 $\pi$/4 shift QPSK를 트렐리스 부호화 변조에 적용시키기 위해 $\pi$/8 shift 8PSK와 BER 특성을 향상시키기 위한 트렐리스 부호화된 $\pi$/8 shift 8PSK-OFDM을 제안한다. 트렐리스 부호화 변조는 위상차에 의한 신호 집합 확장과 분할을 수행한다. 수신측에서 슬라이딩 방식의 다중 심벌 검파를 수행하기 위해서 연속 수신된 신호로부터 L개의 위상차를 추출하고 이를 이용한 비터비 디코더를 설계한다. 슬라이딩 방식의 다중 심벌 검파는 트렐리스 부호화된 $\pi$/8 shift 8PSK-OFDM에서 향상된 BER 성능을 보여준다. 본 논문에서 제안한 다중 심벌 검파를 이용한 $\pi$/8 shift 8PSK-OFDM은 대역폭과 전력의 효율성을 감소시키지 않고 같은 SNR에서 BER 성능을 향상시킬 수 있다는 것을 보여준다. 또한 제안된 디코더 방식과 알고리듬은 다중 반송파뿐만 아니라 전통적인 단일 반송파 변조에도 사용될 수 있다.