• Nuclear Engineering and Technology
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• 제52권11호
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• pp.2652-2659
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• 2020

The methyl iodide (CH₃I) removal performance of tri-ethylene-di-amine impregnated activated carbon (TEDA-AC) used in the air cleaning unit of nuclear power plants (NPPs) should be maintained at least 99% between 24 month-performance test period. In order for evaluating the effectiveness of TEDA-AC on the removal performance of CH₃I in nuclear power plant during the operation of NPPs, the long-term test for up to 15 months was carried out under the simulated operating conditions (e.g., 25 ℃, RH 50%, ppb level poisoning gases injection) at nuclear power plants (NPPs). The TEDA-AC samples were analyzed with the Brunauer-Emmett-Teller (BET) specific surface area and TEDA content as well as CH₃I penetration test. It is clearly evident that more than 99% of CH₃I removal performance of TEDA-AC was observed in the TEDA-AC samples during 15 months of long-term operation under the simulated NPP operating conditions including the ppb level of organic and oxide form of poisoning gases. BET specific surface area and TEDA content that can affect the CH₃I removal performance of TEDA-AC were also maintained as those in new TEDA-AC during 15 months of long-term operation.

• 한국산학기술학회논문지
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• 제12권9호
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• pp.4119-4124
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• 2011

유성음원과 무성음원을 사용하는 멀티펄스 음성부호화 방식에 있어서, 음성신호의 진폭이 증가하거나 감소하는 경우에 음성 파형에 일그러짐이 나타난다. 이것은 대표구간의 멀티펄스를 피치구간마다 복원하는 과정에서 재생 음성신호가 정규화되는 것이 원인으로 작용한다. 이것을 해결하기위하여 본 논문에서는 피치구간마다 멀티펄스의 진폭을 보정하는 방법(AC-MPC)을 제시하였으며, 기존의 MPC와 멀티펄스 진폭을 보정한 AC-MPC의 SNRseg를 평가한 결과, AC-MPC의 남자음성에서 0.7dB, 여자음성에서 0.7dB 개선된 것을 확인할 수 있었다. 결국, MPC에 비해 AC-MPC의 SNRseg가 개선되어 음성파형의 일그러짐을 제어할 수 있었으며, 본 방법은 셀룰러폰이나 스마트폰과 같이 Low Bit Rate의 음원을 사용하여 음성신호를 부호화하는 방식에 활용할 수 있을 것으로 기대된다.

• 한국간담췌외과학회지
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• 제26권2호
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• pp.159-167
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• 2022

Backgrounds/Aims: The optimal timing of percutaneous transhepatic gallbladder drainage (PTGBD) and subsequent laparoscopic cholecystectomy (LC) according to the severity of acute cholecystitis (AC) has not been established yet. Methods: This single-center, retrospective study included 695 patients with grade I or II AC without common bile duct stones who underwent PTGBD and subsequent LC between January 2010 and December 2019. Difficult surgery (DS) (open conversion, subtotal cholecystectomy, adjacent organ injury, transfusion, operation time ≥ 90 minutes, or estimated blood loss ≥ 100 mL) and poor postoperative outcome (PPO) (postoperative hospital stay ≥ 7 days or Clavien-Dindo grade ≥ II postoperative complication) were defined to comprehensively evaluate intraoperative and postoperative outcomes, respectively. Results: Of 695 patients, 403 had grade I AC and 292 had grade II AC. According to the receiver operating characteristic curve and multivariate logistic regression analyses, an interval from symptom onset to PTGBD of > 3.5 days and an interval from PTGBD to LC of > 7.5 days were significant predictors of DS and PPO, respectively, in grade I AC. In grade II AC, the timing of PTGBD and subsequent LC were not statistically related to DS or PPO. Conclusions: In grade I AC, performing PTGBD within 3.5 days after symptom onset can reduce surgical difficulties and subsequently performing LC within 7.5 days after PTGBD can improve postoperative outcomes. In grade II AC, early PTGBD cannot improve the surgical difficulty. In addition, the timing of subsequent LC is not correlated with surgical difficulties or postoperative outcomes.

• 한국자원식물학회지
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• 제31권6호
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• pp.634-640
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• 2018

Aralia cordata (A. cordata), which belongs to Araliaceae, is a perennial herb widely distributed in East Asia. We evaluated the anti-inflammatory effect of stems (AC-S), roots (AC-R) and leaves (AC-L) extracted with 100% methanol of A. cordata and elucidated the potential signaling pathway in LPS-stimulated RAW264.7 cells. The AC-L showed a strong anti-inflammatory activity through inhibition of NO production. AC-L dose-dependently inhibited NO production by suppressing iNOS, COX-2 and $IL-{\beta}$ expression in LPS-stimulated RAW264.7 cells. AC-L inhibited the degradation and phosphorylation of $I{\kappa}B-{\alpha}$, which donated to the inhibition of p65 nuclear accumulation and $NF-{\kappa}B$ activation. Furthermore, AC-L suppressed the phosphorylation of ERK1/2 and p38. These results suggested that AC-L may utilize anti-inflammatory activity by blocking $NF-{\kappa}B$ and MAPK signaling pathway and indicated that the AC-L can be used as a natural anti-inflammatory drugs.

• 한국우주과학회:학술대회논문집(한국우주과학회보)
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• 한국우주과학회 2009년도 한국우주과학회보 제18권2호
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• pp.49.1-49.1
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• 2009

Ground Complex, which is located at Naro Space Center, consists of Assembly Complex(AC) and Launch Complex(LC) which is necessary for successful launch of KSLV-I(NARO). AC consists of Assembly/Testing Building(ATB), Payload Processing Building(PPB), Kick Motor Building(KMB). The purpose of AC is accepting of KSLV-I components, testing, checkout, assembly(disassembly) of the launch vehicle(LV), readiness for transferring LV to LC, accepting of integrated Launch Vehicle(ILV) in case of launch cancellation and short/long time storage, and so on. Qualification tests(QT) for the total system at AC are carried out to check hardware used for operations with first stage unit mockup, upper stage unit Mockup and integrated mockup(GTV). The qualification tests is carried out according to program and procedures of QT. By course of this process, AC is certificated that all the systems and facilities of AC are guaranteed by the fulfillment of technological operations envisioned in the program of qualification tests during the work with the mock-up.

• 조명전기설비학회논문지
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• 제21권10호
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• pp.66-72
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• 2007

이 논문은 직류+60[Hz] 교류 중첩전압에서 신품과 노후된 18[kV] 산화아연 서지피뢰기의 누설전류와 전력손실에 대하여 기술하였다. 최대 50[kV]의 직류+60[Hz] 교류를 발생시킬 수 있는 중첩전압발생장치가 설계되고 제작되었다. 피뢰기의 I-V 특성곡선은 전압중첩률 K의 함수로 측정된다. DC와 AC 전압이 중첩된 I-V, R-V 특성곡선은 순수한 직류와 교류곡선 사이에 있고 저전류 영역에서 교차현상이 나타난다. 그 결과 중첩 전압에서 직류 성분의 증가는 ZnO 피뢰기의 전체 누설전류의 저항성분의 증가를 유발한다. 또한 같은 인가전압에서 피뢰기를 통해 흐르는 누설전류는 상용전원에서 장시간 스트레스 받은 피뢰기가 신품 피뢰기에 비해서 높게 나타났다.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2005년도 제36회 하계학술대회 논문집 A
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• pp.524-526
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• 2005

As a research activity of the project of "Verification Test of Superconducting Power Cable", we measured the AC loss of a short length superconducting power cable. The rating and the length of the cable were 22.9kV, 1,250A and 2.2m. The voltage taps for measuring the AC loss were attached to both ends of the conductor of the superconducting cable. Through the voltage taps and a lock-in amplifier we measured the in-phase component of the voltage($V_x$) with the load current(I). The AC loss was measured by multiplying the in-phase component of the voltage($V_x$) by the load current(I). The value of the AC loss of the superconducting power cable was 1.18W/m/phase/kA at 77.3K, 1atm.

• 한국조명전기설비학회:학술대회논문집
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• 한국조명전기설비학회 2007년도 추계학술대회 논문집
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• pp.263-266
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• 2007

In this paper approves (AC and DC) high voltage by experimental GIS(Gas Insulated Switchgear) chamber and (AC and DC) power source to study breakdown characteristics by pressure(P) change and change of electrode distance(d) at (AC and DC) high voltage of Imitation I-Air, $N_2$ : $O_2$ = 79(%) : 21[%]) to alternate $SF_6$ and achieved research. Gave P change of I-Air to study I-Air's Dielectric Strength using uniform and non-uniform fields(sphere-sphere and Needle-Plane electrode) and studied relations dielectric strength($V_D$) by each P different d.

• 한국조명전기설비학회:학술대회논문집
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• 한국조명전기설비학회 2007년도 추계학술대회 논문집
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• pp.259-262
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• 2007

In this paper approves AC high voltage by experimental GIS(Gas Insulated Switchgear) chamber and AC 300[kV] power source to study breakdown characteristics by pressure(P) change and change of electrode distance(d) at AC high voltage of Imitation Air(I-Air, $N_2$ : $O_2$ = 79(%) : 21[%]) to alternate $SF_6$ and achieved research. Gave P change of I-Air to study I-Air's breakdown characteristics using uniform(Sphere-Sphere electrode) and non-uniform fields(Needle-Plane electrode) and studied relations breakdown voltage($V_B$) by each P different d.

• 한국조명전기설비학회:학술대회논문집
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• 한국조명전기설비학회 2007년도 춘계학술대회 논문집
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• pp.385-388
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• 2007

In this paper approves AC high voltage by experimental GIS(Gas Insulated Switchgear) chamber and AC 300[kV] power source to study breakdown characteristics by pressure(P) change and change of electrode distance(d) at AC high voltage of Imitation Air(I-Air, $N_2$ : $O_2$ = 79[%] : 21[%]) to alternate $SF_6$ and achieved research. Gave P change of I-Air to study I-Air's breakdown characteristics using non-uniform fields(Needle--Plane electrode) and studied relations breakdown voltage ($V_B$) by each P different d.