http://chineseinput.net/에서 pinyin(병음)방식으로 중국어를 변환할 수 있습니다.
변환된 중국어를 복사하여 사용하시면 됩니다.
무변압기형 태양광 인버터의 출력 전류 DC offset 제거 방법
홍기남,최익,최주엽,이상철,이동하,Hong, Ki-Nam,Choy, Ick,Choi, Ju-Yeop,Lee, Sang-Chul,Lee, Dong-Ha 한국태양에너지학회 2012 한국태양에너지학회 논문집 Vol.32 No.suppl3
Since PV PCS uses output current sensor for ac output current control, the sensor's sensing value includes unnecessary offset inevitably. If PV inverter is controlled by the included offset value, it's output current will generate DC offset. The DC offset of output current for trans-less PV inverter is fatal to grid, which results in saturating grid side transformer. Usually DSP controller of PV inverter reads several times sensing value during initial operation and, finally, it's average value is used for offset calibration. However, if temperature changes, the offset changes, too. And also, the switch device is not ideal, both each switching element of the voltage drop difference and on & off time delay difference generate DC offset. Thus, to compensate for deadtime and the switch voltage drop, feedback control by output current DC offset should be provided to compensate additional distortion of the output current. The validity of the proposed method is confirmed through PSIM simulation.
급속 냉각 전로슬래그 골재를 이용한 콘크리트의 차폐특성에 관한 실험적 연구
홍기남 ( Ki Nam Hong ),한상훈 ( Sang Hoon Han ),이상래 ( Sang Rae Lee ) 한국안전학회(구 한국산업안전학회) 2013 한국안전학회지 Vol.28 No.7
This study experimentally evaluated the radiation shielding capacity and mechanical properties of concretes made with rapid chilled converter slag(RCCS) aggregate. Air content, slump test and unit volume weight test were performed for fresh concretes and compressive strength test, chloride penetration test and radiation shielding capacity test were performed for the harden concretes. Compressive strength and chloride penetration resistance of RCCS aggregate concrete was higher and lower than normal concrete, aggregate can be effectively used for the radiation shielding concrete.
홍기남(Kinam Hong),신준수(Junsu Shin),한상훈(Sanghoon Han),서동우(Dongwoo Seo),안광국(Kwangkuk Ahn) 한국지반환경공학회 2014 한국지반환경공학회논문집 Vol.15 No.8
본 연구에서는 초속경 폴리머 모르타르의 역학적 특성이 평가되었다. 이를 위해 총 75개의 모르타르 시편에 대한 압축강도, 휨강도, 부착강도, 동결융해, 길이변화, 그리고 흡수율 시험이 실시되었다. 실험결과로부터 초속경 폴리머 모르타르의 부착강도는 일반 콘크리트보다 50 % 정도 우수하였으며, 동결융해에 대한 저항성은 보통콘크리트보다 뛰어났다. 또한 초속경 폴리머 모르타르의 길이변화와 흡수율은 20 % 정도 일반콘크리트보다 작았다. 그 결과 초속경 폴리머 모르타르는 콘크리트 구조물의 균열을 보수하는데 효과적으로 활용될 수 있을 것으로 평가되었다. In this study, mechanical properties of Very-Rapid Hardening Polymer (VRHP) mortar were investigated. To do it, 75 VRHP mortar specimens were tested by the compressive test, bending test, bonding test, freezing and thawing test, length variation test, and water absorption test. From the test results, it was confirmed that the bond strength of VRHP was higher than that of normal concrete by 50 %, and the resistance of freezing and thawing of VRHP was more excellent than normal concrete. In addition, length variation ratio and water absorption ratio of VRHP were smaller than those of normal concrete by 20 %. Therefore, It should be mentioned that VRHP can be successfully used as the material for repairing the crack of concrete structure.
알칼리 활성 슬래그 콘크리트의 내구성: 콘크리트의 염소이온 확산
홍기남 ( Ki Nam Hong ),박재규 ( Jae Kyu Park ),정규산 ( Kyu San Jung ),한상훈 ( Sang Hun Han ),김재현 ( Jae Hyun Kim ) 한국안전학회(구 한국산업안전학회) 2015 한국안전학회지 Vol.30 No.4
The aim of the present study is to investigate some characteristics of concrete according to addition of blast furnace slag and alkali-activator dosages. Blast furnace slag was used at 30%, 50% replacement by weight of cement, and liquid sulfur having NaOH additives was chosen as the alkaline activator. In order to evaluate characteristics of blast furnace slag concrete with sulfur alkali activators, compressive strength test, total porosity, chloride ions diffusion coefficient test were performed. The early-compressive strength characteristics of blast furnace slag concrete using a sulufr-alkali activators was compared with those of reference concrete and added 30, 50% blast furnace slag concrete. Also, Blast furnace slag concrete using sulfur-alkali activators enhanced the total porosity, chloride ions diffusion coefficient than two standard concrete. Alkali-activated blast furnace slag concrete was related to total porosity, compressive strength and chloride ions diffusion coefficient each others. As a result, it should be noted that the sulfur-alkali activators can not only solve the demerit of blast furnace slag concrete but also offer the chloride resistance of blast furnace slag concrete using sulfur alkali activators to normal concrete.
홍기남 ( Hong Ki Nam ),이한솔 ( Lee Han Sol ),박재규 ( Park Jae Kyu ) 충북대학교 건설기술연구소 2019 建設技術論文集 Vol.38 No.1
일반적인 조건에서, 대부분의 교량시험은 큰 레이놀즈수 범위에서 수행되어지고 있으며, 풍동시험에서는 레이놀즈수를 10∼100배 더 작게하여 시험을 실시하고 있다. 하지만, 공기력계수(플로터 계수)의 작은 차이는 버페팅 응답에 큰 효과를 기칠 수 있기 때문에 정확한 공기력계수를 산정하는 것이 중요하다. 정적 계수 및 플러터 계수는 레이놀즈수에 따라 유사한 교량 단면과는 차이를 보인다. 레이놀즈수에 따라 교량 단면과 버페팅 응답의 공기 역학적 특성의 영향을 추정해야만 한다. 본 연구에서는, 5개의 교량 단면을 통해 전산유체역학)CFD) 해석을 수행하였으며, 정적공기력계수와 플러터 계수가 레이놀즈수의 함수로 계산하였다. 버페팅 응답을 평가하기 위해 시뮬레이션 모델로 금문교(모델 A)와 롤링교(모델 B)를 선택하였다. 두 교량 모델의 버페팅 해석은 CFD 시뮬레이션에 의해 평가된 계수를 사용하여 수행하였다. 최대 변위를 비교한 결과 모델 A는 모델 B보다 더 큰 버페팅 응답을 보였다. 레이놀드 수에 따른 다양한 단면에 대한 버페팅 응답의 경향은 두 교량 모델 모두 유사하게 나타났다. 상대적으로 높은 레이놀즈수 범위에서 버페팅 응답은 유사하며 데크 형상에 영향을 보였다. 유선형 단면의 데크는 높은 레이놀즈수에서 더 작은 효과를 나타내었다. 레이놀즈수로부터 교량 형상에 따른 버페팅 응답 결과는 다르다. 그러므로 교량의 응답을 정확히 평가할 필요가 있다. In a general state, most bridge tests have been performed in a large Reynolds number range, and it also conducted with Reynolds number 10 to 100 times smaller in a wind tunnel test. However, it is important to estimate accurate aeroelastic force coefficients(i.e., flutter derivatives), because a little difference in the aerolastic force coefficients can have a large effect on buffeting response. Static coefficients and flutter derivatives differs from a similar bridge section according to Reynolds number. It should then be estimated the influence of aerodynamic property of bridge section and buffeting response according to Reynolds number. In this study, computational fluid dynamics (CFD) analysis was performed based on five bridge sections, static force coefficients and flutter derivatives were extracted as a function of Reynolds numbers. The Golden Gate Bridge(model A) and Lulling Bridge(model B) are selected as a simulation model to evaluate buffeting response. Buffeting analysis of two bridge models was performed using the coefficients estimated by CFD simulations. It is shown that the model A has larger buffeting response than the Lmodel B, as a result of comparing peak displacements. The trends of buffeting response for various sections according to Reynolds number are similarly shown on both bridge models. It is shown that the effect of deck shape has on the buffeting response has smaller in a relatively high Reynolds number range. It is also indicated that more streamlined section deck has smaller effects in high reynolds number. The result of buffeting response differs according to the shape of bridge by Reynolds number, therefore, it is necessary to accurately evaluate the bridge response.