• The Transactions of the Korean Institute of Electrical Engineers P
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• v.59 no.2
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• pp.185-190
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• 2010

This paper presents the estimation on switching technique via output power source analysis of power conversion unit in electric railway vehicle. The focus of this study suggested an alternative on critical problems by using head electric power(HEP). To achieve this, we have measured output power of HEP, and measurement devices set up at output of transformer connected HEP to analysis quality on output power source of head electric power(HEP) unit in electric railway vehicle. Using results of measurement of it, parameters are assumed for simulation to confirm estimation on switching technique. It is confirmed that switching technique is Selected Harmonic Elimination PWM(SHEPWM) and inverter switching frequency is less than 500[Hz]. Throughout experiment and simulation, it is estimated that switching technique used HEP is advanced SHEPWM and switching frequency is about 300[Hz]. Also leakage inductance in transformer is about $180[{\mu}H]$ less than $365[{\mu}H]$ known.

• Journal of Pharmacopuncture
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• v.20 no.3
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• pp.207-212
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• 2017

Objectives: Study of the mechanisms involved in cancer progression suggests that cyclooxygenase enzymes play an important role in the induction of inflammation, tumor formation, and metastasis of cancer cells. Thus, cyclooxygenase enzymes could be considered for cancer chemotherapy. Among these enzymes, cyclooxygenase 2 (COX-2) is associated with liver carcinogenesis. Various COX-2 inhibitors cause growth inhibition of human hepatocellular carcinoma cells, but many of them act in the COX-2 independent mechanism. Thus, the introduction of selective COX-2 inhibitors is necessary to achieve a clear result. The present study was aimed to determine the growth-inhibitory effects of new analogues of chalcone epoxide as selective COX-2 inhibitors on the human hepatocellular carcinoma (HepG2) cell line. Methods: Estimation of both cell growth and the amount of prostaglandin E2 (PGE2) production were used to study the effect of selective COX-2 inhibitors on the hepatocellular carcinoma cell. Cell growth determination has done by MTT assay in 24 h, 48 h and 72 h, and PGE2 production has estimated by using ELYSA kit in 48 h and 72 h. Results: The results showed growth inhibition of the HepG2 cell line in a concentration and time-dependent manner, as well as a reduction in the formation of PGE2 as a product of COX-2 activity. Among the compounds those analogues with methoxy and hydrogen group showed more inhibitory effect than others. Conclusion: The current in-vitro study indicates that the observed significant growth-inhibitory effect of chalcone-epoxide analogues on the HepG2 cell line may involve COX-dependent mechanisms and the PGE2 pathway parallel to the effect of celecoxib. It can be said that these analogues might be efficient compounds in chemotherapy of COX-2 dependent carcinoma specially preventing and treatment of hepatocellular carcinomas.

• Nuclear Engineering and Technology
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• v.30 no.6
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• pp.531-540
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• 1998

The DYLAM-3 code which overcomes the limitation of event tree/fault tree was applied to LOOP (Loss of Off-site Power) in the mid-loop operation employing HEPs (Human Error Probabilities) supplied by the ASEP (Accident Sequence Evaluation Program) and the SEPLOT (Systematic Evaluation Procedure for Low power/shutdown Operation Task) procedure in this study. Thus the time history of core uncovery frequency during the mid-loop operation was obtained. The sensitivity calculations in the operator's actions to prevent core uncovery under LOOP in the mid-loop operation were carried out. The analysis using the time dependent HEP was performed on the primary feed & bleed which has the most significant effect on core uncovery frequency. As the result, the increment of frequency is shown after 200 minutes duration of simulation conditions. This signifies the possibility of increment in risk after 200 minutes. The primary feed & bleed showed the greatest impact on core uncovery frequency and the recovery of the SCS (Shutdown Cooling System) showed the least impact. Therefore the efforts should be taken on the primary feed & bleed to reduce the core uncovery frequency in the mid-loop operation. And the capability of DYLAM-3 in applying to the time dependent concerns could be demonstrated.

• Nuclear Engineering and Technology
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• v.54 no.3
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• pp.896-908
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• 2022

As a part of probabilistic risk (or safety) assessment (PRA or PSA) of nuclear power plants (NPPs), the primary role of human reliability analysis (HRA) is to provide credible estimations of the human error probabilities (HEPs) of safety-critical tasks. In this regard, it is vital to provide credible HEPs based on firm technical underpinnings including (but not limited to): (1) how to collect HRA data from available sources of information, and (2) how to inform HRA practitioners with the collected HRA data. Because of these necessities, the U.S. Nuclear Regulatory Commission and the Korea Atomic Energy Research Institute independently developed two dedicated HRA data collection systems, SACADA (Scenario Authoring, Characterization, And Debriefing Application) and HuREX (Human Reliability data EXtraction), respectively. These systems provide unique frameworks that can be used to secure HRA data from full-scope training simulators of NPPs (i.e., simulator data). In order to investigate the applicability of these two systems, two papers have been prepared with distinct purposes. The first paper, entitled "SACADA and HuREX: Part 1. The Use of SACADA and HuREX Systems to Collect Human Reliability Data", deals with technical issues pertaining to the collection of HRA data. This second paper explains how the two systems are able to inform HRA practitioners. To this end, the process of estimating HEPs is demonstrated based on feed-and-bleed operations using HRA data from the two systems.

• Journal of Life Science
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• v.17 no.10
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• pp.1381-1386
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• 2007

To elucidate the changes in physiological activities of Scutellariae baicalensis by heating, composition analysis with HPLC and evaluation of physiological activities of extracts were conducted. HPLC analysis of CW(water extract at room temperature) and CHW(heat treated CW) indicated that two distinctive peaks in the HPLC chromatogram were disappeared after boiling and additional peak was newly observed. This observation suggested that certain chemical changed in the extract occurred by heat treatment. In the estimation of physiological activities, CW showed higher ACE inhibiting activity than CHW. In the case of cytotoxic activity against cancer cells, CW exhibited higher activity than CHW against CCL-185. On the other hand, CHW showed higher activity than CW against HeLa, SNU-601 and HepG2. In addition, CHW showed the inhibitory effect on melanogenesis (80% inhibition) while CW did not show any activity.