IEC 60364의 접지방식에 기반한 안전성 평가 시험장치의 모델링 및 구현에 관한 연구

김순식(Soon-Sik Kim),한병길(Byeong-Gill Han),이후동(Hu-Dong Lee),페레이라 마리토(Marito Ferreira),노대석(Dae-Seok Rho) 한국산학기술학회 2021 한국산학기술학회논문지 Vol.22 No.6

국내 접지방식은 2021년부터 IEC 60364에서 제시하는 접지방식을 새롭게 채택하고 있다. 이 접지방식은 인체접촉사고 발생 시, 접촉전압과 통과전류에 대한 특성이 다양하게 나타날 수 있어, 인체에 대한 안전성 평가가 구체적으로 요구되고 있다. 또한, 한국전기안전공사나 대한전기협회에서 IEC 60364의 접지방식에 대한 안전기술 교육을 부분적으로 수행하고 있지만, 안전성을 평가할 수 있는 시험장치가 미흡하여, 전기안전관리자에 대한 교육이 어려운 실정이다. 따라서, 본 논문에서는 IEC 60364의 접지방식별 안전성 평가를 수행할 수 있는 시험장치를 모델링하고, 이를 바탕으로 시험장치를 구현한다. 즉, 전력계통 상용해석 프로그램인 PSCAD/EMTDC를 이용하여, 계통 전원부, 접지방식별 시험장치부, 보조장치부로 구성된 안전성 평가 시험장치의 모델링을 제시하고, 계통전원부, TT접지방식 시험장치부, TN-S접지방식 시험장치부, 모니터링부로 구성된 안전성 평가 시험장치를 구현한다. 상기의 모델링과 시험장치를 이용하여, TT접지방식과 TN-S접지방식의 인체 안전성 특성을 분석한 결과, TT접지방식의 경우 고장점 임피던스가 0[Ω], 10[Ω], 100[Ω]에서 인체 통과전류는 각각 104[㎃], 87.4[㎃], 35.5[㎃]가 산정되었고, TN-S접지방식의 경우 54.9[㎃], 4.1[㎃], 0.4[㎃]가 산정됨에 따라, TN-S접지방식이 TT접지방식에 비하여 감전에 대한 보호가 우수함을 알 수 있고, 저압수용가에서 사용 중인 TT 접지방식에서 TN-S 접지방식으로 전환하면 감전에 대한 보호성능을 향상시킬 수 있음을 알 수 있었다. A novel grounding system, which is presented in IEC 60364, has been adopted since 2021. A safety evaluation for the hu㎃n body on the grounding system is required due to the various characteristics of the touch voltage and current passing when the human body experiences an electric shock. The Korea Electrical Safety Corporation (KESCO) and Korea Electric Association (KEA) have been conducting a safety technical education on the grounding system. On the other hand, it is difficult to instruct the electrical safety manager because of a lack of safety evaluations for the test equipment on the grounding system. Therefore, this paper modeled and implemented a test device for a safety evaluation depending on the grounding system of IEC 60364. Namely, this paper presents the modeling of the test device for a safety evaluation using PSCAD/EMTDC S/W, which is composed of an AC grid section, s test device section on the grounding system, and a sub-device section. This paper implemented a test device for safety evaluation, which consisted of an AC grid section, TT grounding system section, TN-S grounding system section, and monitoring section. From the simulation and test results with the safety characteristics of the hu㎃n body in the TT and TN-S grounding system, when the fault impedances are 0[Ω], 10[Ω], and 100[Ω], the currents passing through the hu㎃n body in the TT grounding system are 104[㎃], 87.4[㎃], and 35.5[㎃], respectively. The corresponding currents in the TN-S grounding system are 54.9[㎃], 4.1[㎃], and 0.4[㎃], respectively. Based on the results, the protection performance for an electric shock to the hu㎃n body in the TN-S system is better than the TT system. This can be improved when the existing grounding system is changed from the TT system to the TN-S system.

前期加耶의 對外關係 : 釜山·金海勢力의 經濟的基盤과 對外關係를 中心으로

도동열,허재혁 동의공업대학 1999 論文集 Vol.25 No.1

There were many restrictions in the study about ancient Kaya located in southern area of Korea because of the political use of Japan and the shortage of historical materials. But new occasion came because of the archaelogical studies about the outcome of the excavations in downstream area of the NakDong-river(洛東江). Kaya can be divided into two periods -The first term and The preceding term) -and the changing point of time is analogized as 4∼5th century. The center of the first term of Kaya was located at Kimhae(金海). Kaya prospered through the production of iron and overseas trade. The evidence of prosperity can be searched on the cultural phenomenons of the ancient tombs at Daesung-dong(大成洞) that many remains bespeak mightly influence were excavated until the first half of the 5th century. But after that, preceding term kaya declined rapidity. This event can be connected with description of the southern expedition by Kokuryo(高句麗), recorded on the monument of the King Kwangeaeto(廣開土) The Great which is known as the most important material on the Korean ancient history. After that, A1a-kuk(阿羅國) at Haman(咸安) and Taekaya(大加耶) at Koryung(高靈) became new center of Kaya area located in southern Korea until the destruction.

DMBA 매식과 방사선 조사로 유도된 백서 타액선 종양에서 H-ras 암유전자의 활성화

유동수,허기순,최종환,최순철,박태원 大韓口腔顎顔面 放射線學會 1998 Imaging Science in Dentistry Vol.28 No.1

Cellular transforming genes have been identified in a number of different tumor cell lines and tumor types. A significant number of these oncogenes belong to the ras gene family. The ras gene family consists of three closely related genes:H-ras, K-ras and N-ras which code for a related 21 kDa protein. Mutations in codon 12, 13 and 61 of one of the three ras genes convert these genes into acute oncogenes. The presence of H-ras gene mutations has important prognostic implications in various tumors. Each genomic DNA was isolated from tumors induced by implantation with DMBA, or by treatment with DMBA-implantation/irradiation. When genome DNA was transfected into NIH 3T3 cells and investigated by two-step PCR-RFLP, the following results were concluded: 1. Transformation foci developed in two groups then the genome DNA of two experimental groups were transfected into NIH 3T3 cells. 2. Transformation efficiency was 0.01-0.02 foci/㎍DNA in the experimental group with the DMBA-implantation/irradiation according to results of transfection assay. 3. When the point mutation of H-ras gene was investigated by a two-step PCR-RFLP, there was 13.9%(5/36) in the experimental group with the DMBA implantation, 15.4%(6/39) in the expermetal group with the DMBA-implantation/irradiation. 4. The point mutation in codon 12 and 61 of H-ras was 5.6%(2/36) and 8.3%(3/36) in the experimental group with the DMBA implantation. 5. The point mutation in codon 12 and 61 of H-ras gene was 7.7%(3/39) in the experimental group with the DMBA-implantation/irradiation.

섬유강화 고분자 복합판의 기계적 성질에 미치는 섬유길이와 섬유함유율의 영향

이상동,김혁,허업,최종대,이동기 조선대학교 에너지.자원신기술연구소 1997 에너지·자원신기술연구소 논문지 Vol.19 No.2

This paper describes effect of chopped strand length fiber content and moisture absorption on mechanical properties of fiber-reinforced polymeric composites. It was extrusion compounded long fiber-reinforced polypropylene containing 20, 30 and 50 percent and short fiber-reinforced ABS and PAS containing 30 percent b37 the weight of glass fiber. The test methods of ASTM D638, D3410-87 and D79OM are applied for tensile, compressive and bending tests respectively. The results show that, in the case of 0.2% moisture absorption, the residual strength decreases dramatically.

급성심근경색후 발생한 심실중격결손 2례

김태희,이재호,김애란,허민영,문치숙,정수룡,김대경,김두일,김동수 인제대학교 백병원 2002 仁濟醫學 Vol.23 No.4

Ventricular septal defect remains an infrequent but devastating complication of acute MI. Approximately 1∼3% of cases of acute myocardial infarction are complicated by ventricular septal rupture in the prethrombolytic era and the incidence has decreased to 0.2% with reperfusion therapy. This mechanical complication usually occurs within the first 10 to 14 days when necrotic tissue is most abundant and the collateral coronary circulation is not well developed. This lesion is generally associated with complete coronary obstruction rather than severe stenosis. Rupture of the ventricular septum is a severe mechanical complication of acute myocardial infarction, usually resulting in death unless surgical repair is performed. The bad prognosis of this event within the first 2 weeks indicates the need for early surgical rapair. This complication is more frequent after the first acute myocardial infarction in the elderly and secondary to a transmural myocardial infarction. We report two cases of ventricular septal rupture after acute myocardial infarction.

3차원 전산화단층촬영 영상을 이용한 얼굴 연조직 두께 계측

정호걸,김기덕,한승호,신동원,허경석,이제범,박혁,박창서 대한구강악안면방사선학회 2006 Imaging Science in Dentistry Vol.37 No.1

Purpose : To evaluate accuracy and reliability of program to measure facial soft tissue thickness using 3D computed tomographic images by comparing with direct measurement. Materials and Methods : One cadaver was scanned with a Helical CT with 3 mm slice thickness and 3 mm/sec table speed. The acquired data was reconstructed with 1.5 mm reconstruction interval and the images were transferred to a personal computer. The facial soft tissue thickness were measured using a program developed newly in 3D image. For direct measurement, the cadaver was cut with a bone cutter and then a ruler was placed above the cut side, The procedure was followed by taking pictures of the facial soft tissues with a high-resolution digital camera. Then the measurements were done in the photographic images and repeated for ten times. A repeated measure analysis of variance was adopted to compare and analyze the measurements resulting from the two different methods. Comparison according to the areas was analyzed by Mann-Whitney test. Results : There were no statistically significant differences between the direct measurements and those using the 3D images (p>0.05). There were statistical differences in the measurements on 17 points but all the points except 2 points showed a mean difference of 0.5 mm or less. Conclusion : The developed software program to measure the facial soft tissue thickness using 3D images was so accurate that it allows to measure facial soft tissues thickness more easily in forensic science and anthropology. (Korean J Oral Maxillofac Radiol 2006; 36 : 49-54)

제주마의 체형에 관한 연구

강민수,정창조,강태숙,박희석,김동후,정재준 제주대학교 농과대학 제주도축산문제연구소 1986 畜産論叢 Vol.1 No.1

Influence of Intravenous Contrast Medium on Dose Calculation Using CT in Treatment Planning for Oesophageal Cancer

Li, Hong-Sheng,Chen, Jin-Hu,Zhang, Wei,Shang, Dong-Ping,Li, Bao-Sheng,Sun, Tao,Lin, Xiu-Tong,Yin, Yong Asian Pacific Journal of Cancer Prevention 2013 Asian Pacific journal of cancer prevention Vol.14 No.3

Objective: To evaluate the effect of intravenous contrast on dose calculation in radiation treatment planning for oesophageal cancer. Methods: A total of 22 intravein-contrasted patients with oesophageal cancer were included. The Hounsfield unit (HU) value of the enhanced blood stream in thoracic great vessels and heart was overridden with 45 HU to simulate the non-contrast CT image, and 145 HU, 245 HU, 345 HU, and 445 HU to model the different contrast-enhanced scenarios. 1000 HU and -1000 HU were used to evaluate two non-physiologic extreme scenarios. Variation in dose distribution of the different scenarios was calculated to quantify the effect of contrast enhancement. Results: In the contrast-enhanced scenarios, the mean variation in dose for planning target volume (PTV) was less than 1.0%, and those for the total lung and spinal cord were less than 0.5%. When the HU value of the blood stream exceeded 245 the average variation exceeded 1.0% for the heart V40. In the non-physiologic extreme scenarios, the dose variation of PTV was less than 1.0%, while the dose calculations of the organs at risk were greater than 2.0%. Conclusions: The use of contrast agent does not significantly influence dose calculation of PTV, lung and spinal cord. However, it does have influence on dose accuracy for heart.

Additive Process Using Femto-second Laser for Manufacturing Three-dimensional Nano/Micro-structures

Dong-Yol Yang,Tae Woo Lim,Yong Son,Hong-Jin Kong,Kwang-Sup Lee,Dong-Pyo Kim,Sang Hu Park 한국정밀공학회 2007 International Journal of Precision Engineering and Vol.8 No.4

The two-photon stereolithography (TPS) process is a promising technique for the fabrication of real three-dimensional (3D) nano/micro-structures via application of a femto-second laser. In TPS, when a near-infrared ultrashort-pulsed laser is closely focused onto a confined volume of photocurable resin, only the local area at the center of the focus is cured. Therefore, real 3D microstructures with resolution under the diffraction limit can be fabricated through a layer-by-layer accumulative technique. This process provides opportunities to develop neo-conceptive nano/micro devices in IT/BT industries. However, a number of issues, including development of effective fabrication methods, highly sensitive and functional materials, and neo-conceptive devices using TPS, must be addressed for the realization of industrial application of TPS. In this review article. we discuss our efforts related to TPS: effective fabrication methods, diverse two-photon curable materials for high functional devices, and applications.

Overexpressed Derlin-1 Inhibits ER Expansion in the Endothelial Cells Derived from Human Hepatic Cavernous Hemangioma

( Dong Hu ),( Yu Liang Ran ),( Xing Zhong ),( Hai Hu ),( Long Yu ),( Jin Ning Lou ),( Li Xing Sun ),( Zhi Hua Yang ) 생화학분자생물학회 2006 BMB Reports Vol.39 No.6