전동기 구동용 전력 변환기에 대한 전력소자의 열적 특성 해석

조문택(Moontaek Cho),이충식(Chungsik Lee),이상복(SangBock Lee) 한국방사선학회 2012 한국방사선학회 논문지 Vol.6 No.6

논문에서는 전력용반도체 소자의 수명예측으로 기초적인 동작환경과 구동시간들을 기록하였다. 전력변환기의 제어기에 의하여 전력소자의 구동시간과 방렬기의 온도 등 동작환경을 누적하여 기록하고 이를 확인할 수 있도록 하므로써 전력용 반도체소자는 그 구조에서 수명은 반도체 칩의 온도변화의 크기와 반복회수로 사용기간을 보증하고 있으므로 이에 의한 수명의 예측으로 유지보수 또는 교체가 적절한 시점에서 이루어질 수 있다고 판단된다. In this paper, the basic behavior of the environment and the driving time as a prediction of the lifetime of the power semiconductor devices were recorded. Radiator of a power device driving time and temperature operating environment, including cumulative record by the controller of the power converter, and doing it so you can see the power semiconductor devices for the life of the structure that the size of the change in the temperature of the semiconductor chip and the number of iterations to maintenance warranty period because of a lifetime by forecasting or replacement can be made at the appropriate time that is considered.

병원내 온도와 습도조절을 위한 태양광 발전 시스템 설계

조문택(Moontaek Cho),이충식(Chungsik Lee),백종무(Jongmu Baek) 한국방사선학회 2011 한국방사선학회 논문지 Vol.5 No.3

본 논문에서는 온도와 습도 및 냉·난방을 조절하여 건물 내의 쾌적한 환경을 제공하기 위한 승압쵸퍼와 PWM 전압형 인버터로 구성된 태양광 발전 시스템을 제안하였다. 이 시스템은 안정된 변조를 위해 원칩 마이크로프로세서를 사 용하여 동기신호와 제어신호로 처리하였다. PWM 전압형 인버터와 위상의 동기를 위하여 계통전압을 검출하여 계통전압과 인버터 출력을 동상 운전하므로 잉여전력을 연계할 수 있게 하였으며, 건물이나 병원 등 특정 건물의 온도 및 습도센서에 적용하여 양호한 동특성을 얻을 수 있었다. 또한 시스템에 적용한 결과 고역률과 저고조파 출력을 유지함으로써 부하와 계통에 전력이 안정하게 공급될 수 있도록 제어하여 좋은 결과를 얻을 수 있었다. In this paper we propose an improved PV generation systems. Improved systems for temperature and humidity controlled heating and air conditioning offers a pleasant environment within the building, set up chopper and consists of a PWM voltage type inverter. The proposed system is stable modulation for a one-chip microprocessor using the synchronous signal and control signals was treated. The proposed system is a PWM voltage type inverter and phase of the synchronous to the grid voltage to detect the system voltage and inverter output to drive the statue, so surplus power to connection was able to, certain buildings such as buildings or hospitals, temperature and humidity sensor is applied to the good dynamic characteristic could be obtained. In addition, the system was applied to the high power factor and low-frequency harmonics by maintaining the output load and grid to power to be supplied to a stable control could get a good result.

공간벡터 PWM 방식을 이용한 태양광 발전 시스템 제어

조문택 ( Moontaek Cho ),최혜길 ( Haegill Choi ),이충식 ( Chungsik Lee ),백종무 ( Jongmu Baek ) 한국방사선학회 2010 한국방사선학회 논문지 Vol.4 No.3

본 논문에서는 태양광 발전시스템을 이용한 PWM(Pulse Width Modulation) 전압형 인버터를 전력변환기로 구성하였고, 안정된 변조를 위해서 동기신호와 제어신호를 56F8323 마이크로프로세서에 의해서 처리하였다. PWM 전압형 인버터는 태양전지가 연속 발전할 수 없는 단점을 보완하기 위해 일반 상용전원과 연계함으로써 약 10~20[%]의 전력 절감 효과를 얻을 수 있는 에너지 절약 전원 복합형 전력변환장치로 구성하였다. 그리고 PWM 전압형 인버터와 위상동기를 위해서 계통전압을 검출하고 계통전압과 인버터 출력을 동상 운전하므로 잉여전력을 계통과 연계할 수 있게 하였다. 또한, 고조파를 절감한 출력을 유지함으로써 부하와 계통에 전력이 안정하게 공급될 수 있도록 제어 시스템을 적용하여 좋은 결과를 얻을 수 있었다. In this paper, a photovoltaic system is designed with PWM(Pulse Width Modulation) voltage source inverter. Proposed synchronous signal and control signal was processed by 56F8323 microprocessor for stable modulation. The PWM voltage source inverter using inverter consists of complex type of electric power converter to compensate for the defect, that is solar cell cannot be developed continuously by connecting with the source of electric power for ordinary use. It can cause the effect of saving electric power, from 10 to 20[%]. The PWM voltage source inverter operates in situation that its output voltage is in same phase with the utility voltage. In addition, I connected extra power to the system through operation the system voltage and inverter power in a synchronized way by extracting the system voltage so that the phase of the system and PWM voltage inverter can be synchronized. In the system of this research showed good results after being controlled in order to provide stable power to the load and the system through maintaining and low output power of harmonics.

회로해석을 위한 전자부품의 모델링

조문택(Moontaek Cho),홍봉화(Bongwha Hong) 한국정보기술학회 2014 한국정보기술학회논문지 Vol.12 No.5

The purpose of this paper is to verify the appropriation of power electronics circuit by applying the most powerful and widely used simulator ORCAD/PSPICE and MATLAB/SIMULINK for adapted variable control technics. Power semiconductor macro modeled by SIMULINK such as diode, thyristor, transistor. Loads are modeled by SIMULINK such as a resistor, inductor, DC motor and AC induction motor. Furthermore DC motor & AC induction motor are modeled by PSPICE through their algorithms. For proved these modelings accurate, simulation techniques which are generally used in the field of power electronics circuits are adapted in power electronics and systems. As a results, the characteristics of micro IGBT model device and macro IGBT model in cycloconverter are almost identical to the result of actual experiments. And, speed sensorless vector control of induction motor algorithms are modeled by taking use of closed loop and SIMULINK modeling simulation are almost same.

LA-ICP-MS trace element analysis of arsenopyrite from the Samgwang gold deposit, South Korea, and its genetic implications

Lee, Moontaek,Shin, Dongbok,Yoo, Bongchul,Im, Heonkyung,Pak, Sangjoon,Choi, Sunki Elsevier 2019 Ore geology reviews Vol.114 No.-

<P><B>Abstract</B></P> <P>The Samgwang deposit, previously classified as an orogenic gold deposit, consists of several structurally controlled auriferous quartz veins hosted by metasedimentary rocks of the Precambrian Gyeonggi massif, South Korea. The gold at Samgwang occurs as electrum commonly associated with arsenopyrite. Laser ablation-inductively coupled plasma-mass spectrometry (LA-ICP-MS), coupled with ore microscopy, was conducted on Au and trace elements distributed in arsenopyrite grains contained in quartz vein and wall rock samples. Resulting profiles for Au, Co, Ni, and Sb were relatively flat and showed little variability, indicating that the elements were relatively homogeneously distributed and exchanged via substitution in arsenopyrite, while variability and noisy depth profiles inferred that Pb was present as tiny inclusions or discrete particles. Furthermore, measured gold concentrations were typically higher in arsenopyrite grains from laminated quartz veins (avg. 2.07 ppm) than in grains from massive quartz veins (avg. 0.26 ppm) and wall rock samples (avg. 0.33 ppm). In the case of wall rock and massive quartz vein samples, arsenopyrite grains of euhedral shape illustrate an element distribution pattern whereby Au concentrations tend to decrease towards the rims of the analyzed grains. In contrast, the rims of arsenopyrite grains in laminated quartz vein samples recorded much higher Au concentrations of up to 20.1 ppm, with increasing Pb, Bi, and Ag, particularly within domains of fractured or recrystallized arsenopyrite grains. The newly acquired LA-ICP-MS data, along with textural evidence, may be interpreted in terms of the release and remobilization of invisible gold that was originally locked up in the arsenopyrite. This release is linked to late deformation and hydrothermal event during which the remobilized invisible gold was redeposited as electrum. In addition, there is evidence for the introduction of additional gold and other precious and base metals by the late-stage hydrothermal fluids. Based on the above and in contrast to previous genetic models, we propose a more complex metallogenic concept for Samgwang in which the economically important gold enrichment process was genetically related to intrusive activity during the waning stages of Jurassic to Early Cretaceous Daebo orogenesis.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Gold content of euhedral arsenopyrite decreases towards the crystal margin. </LI> <LI> Invisible gold remobilized to form electrum observed in veinlets cutting or as fracture-fill in arsenopyrite. </LI> <LI> Gold enrichment process can be linked to formation of late-orogenic intrusion-related gold deposits. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>

LA-ICP-MS를 이용한 삼광 금-은광상 유비철석의 미량원소 분석

이문택(Moontaek Lee),유봉철(Bongchul Yoo),신동복(Dongbok Shin),임헌경(Heonkyung Im),박상준(Sangjoon Pak),최선기(Sunki Choi) 대한지질학회 2017 대한지질학회 학술대회 Vol.2017 No.10

자연재해 및 방사능 오염 모니터링용 USN 식물공장관리 방법 및 시스템 개발

주해종(Haejong Joo),조문택(Moontaek Cho),이충식(Chungsik Lee),백종무(Jongmu Baek) 한국방사선학회 2011 한국방사선학회 논문지 Vol.5 No.6

본 논문은 재난재해와 방사선 오염으로부터 안전한 농작물 관리를 위한 플랫폼, 그리고 식물 생장 모니터링 시스템을 제안하였다. 또한, 식물생장을 모니터링하여 식물공장 내에서 생장하는 식물의 크기를 효율적으로 측정할 수 있는 시스템을 개발하였다. 본 연구에 따른 기대효과는 첫째, 자연재해와 방사능오염 감시를 통해 신속하고 정확한 대처 기능으로 농산물 품질과 생산성 향상을 가져올 수 있다. 둘째, 식물의 크기 측정 데이터를 유지 관리하는데 소요되는 시간을 절약하여 경비를 절감할 수 있다. 마지막으로 식물 공장 관리자의 작업 효율을 향상시킬 수 있다. In this paper, monitoring system and platform of plant growth are suggested which are required by safe crop management about disaster and radiation pollution. In addition, by monitoring plant growth, the growth of plants that can measure the size of the efficient system was developed. The expected effect of this study, first, through natural disasters and radioactive contamination monitors produce fast and accurate response function can result in improved quality and productivity. Second, the size of the plant required to maintain the measurement data can save time and expense savings. Finally, plant managers can improve work efficiency.

Prevalence and risk indicators of peri-implantitis in Korean patients with a history of periodontal disease: a cross-sectional study

Goh, Mi-Seon,Hong, Eun-Jin,Chang, Moontaek Korean Academy of Periodontology 2017 Journal of Periodontal & Implant Science Vol.47 No.4

Purpose: The aim of this study was to analyze the prevalence and risk indicators of peri-implantitis in Korean patients with history of periodontal disease. Methods: A total of 444 patients with 1,485 implants were selected from patients who had been treated at the Department of Periodontology, Chonbuk National University Dental Hospital between July 2014 and June 2015. A group with a history of peri-implantitis (HP) (370 patients with 1,189 implants) and a group with a current peri-implantitis (CP) (318 patients with 1,004 implants) were created based on the radiographic and clinical assessments of implants. The prevalence of peri-implantitis was calculated at both the patient and implant levels. The influence of risk variables on the occurrence of peri-implantitis was analyzed using generalized estimating equations analysis. Results: The prevalence of peri-implantitis in the HP and CP groups ranged from 6.7% to 19.7%. The cumulative peri-implantitis rate in the HP group estimated with the Kaplan-Meier method was higher than that in the CP group over the follow-up period. Among the patient-related risk variables, supportive periodontal therapy (SPT) was the only significant risk indicator for the occurrence of peri-implantitis in both groups. In the analysis of implant-related variables, implants supporting fixed dental prosthesis (FDP) and implants with subjective discomfort was associated with a higher prevalence of peri-implantitis than single implants and implants without subjective discomfort in the HP group. The presence of subjective discomfort was the only significant implant-related variable predictive of peri-implantitis in the CP group. Conclusions: Within the limitations of this study, the prevalence of peri-implantitis in Korean patients with a history of periodontal disease was similar to that reported in other population samples. Regular SPT was important for preventing peri-implantitis. Single implants were found to be less susceptible to peri-implantitis than those supporting FDP. Patients' subjective discomfort was found to be a strong risk indicator for peri-implantitis.

Knowledge, Attitude and Behavior of High School Students Regarding Irradiated Foods

최윤석(Yoonseok Choi),송종남(Jongnam Song),정문택(Moontaek Jeong),최남길(Namgil Choi),한재복(Jaebok Han) 한국방사선학회 2014 한국방사선학회 논문지 Vol.8 No.6

방사선조사식품에 대한 광범위한 국민적 공감대를 형성하고 국민이해를 제고하기 위한 커뮤니케이션 전략의 일환으로 교육적인 개입전략을 계획하는데 필요한 기초 근거자료를 제공하고자 하였다. 일반인 중 교육의 파급효과가 높은 고등학생을 대상으로 방사선조사식품에 대한 지식, 태도 및 행위 수준을 조사한 결과 방사선조사식품에 대해 정보를 습득한 경험이 없는 학생이 82.9%(627명), 교육 경험이 없는 학생이 89.3%(675명)로 압도적으로 많았다. 교육을 받지 못한 이유로는 교육의 기회가 없어서(88.2%)가 대부분이었다. 방사선조사식품에 대한 지식수준은 1.71점(10점 만점)으로 매우 낮은 수준을 나타냈고, 방사선조사식품의 안전성에 대한 태도수준도 2.76점(5점 만점)으로 비교적 낮은 태도수준을 나타냈다. 이는 방사선조사식품에 대한 매우 낮은 지식과 부정적 태도를 가지고 있기 때문에 방사선조사식품을 구입 및 섭취로 이어지는 행위수준은 낮을 수밖에 없다고 예측할 수 있다. 또한 방사선조사식품에 대한 교육경험이 있는 학생이 교육 경험이 없는 학생보다 방사선조사식품에 대한 긍정적 태도수준이 더 높게 나타났다(p<0.001). 이러한 결과는 방사선조사식품에 대한 지식제공 뿐만 아니라 올바른 태도형성을 위한 교육을 함께 제공할 필요가 있음을 알 수 있다. This paper presents basic supporting data necessary for planning an educational intervention strategy as part of a communication strategy that would form an extensive national consensus on and enhance national understanding of irradiated foods. A survey was conducted to collect data on the knowledge, attitude, and behavior with regard to irradiated foods among high school students, on whom education has a great ripple effect compared with the general public. The results show that 82.9% (627 students) have acquired no information, whereas 89.3% (675 students) have received no education on irradiated foods. The reason for these overwhelmingly large percentages is the lack of available opportunity for education(88.2%). Their level of knowledge on irradiated foods scores 1.71 points (out of 10 points), which is very low, whereas their attitude toward the safety of irradiated foods scores 2.76 points (out of 5 points), which is relatively low as well. As such, we predict that their tendency to purchase and consume irradiated foods is low, given their very low level of knowledge of and negative attitude toward irradiated foods. The students who have been educated on irradiated foods show a higher level of positive attitude (p<0.001) toward irradiated foods compared with those who have had no education. This result suggests the need to provide high school students with knowledge on irradiated foods as well as education in the same to help them form a proper attitude toward these food items.

Alterations of papilla dimensions after orthodontic closure of the maxillary midline diastema: a retrospective longitudinal study

Jeong, Jin-Seok,Lee, Seung-Youp,Chang, Moontaek Korean Academy of Periodontology 2016 Journal of Periodontal & Implant Science Vol.46 No.3

Purpose: The aim of this study was to evaluate alterations of papilla dimensions after orthodontic closure of the diastema between maxillary central incisors. Methods: Sixty patients who had a visible diastema between maxillary central incisors that had been closed by orthodontic approximation were selected for this study. Various papilla dimensions were assessed on clinical photographs and study models before the orthodontic treatment and at the follow-up examination after closure of the diastema. Influences of the variables assessed before orthodontic treatment on the alterations of papilla height (PH) and papilla base thickness (PBT) were evaluated by univariate regression analysis. To analyze potential influences of the 3-dimensional papilla dimensions before orthodontic treatment on the alterations of PH and PBT, a multiple regression model was formulated including the 3-dimensional papilla dimensions as predictor variables. Results: On average, PH decreased by 0.80 mm and PBT increased after orthodontic closure of the diastema (P<0.01). Univariate regression analysis revealed that the PH (P=0.002) and PBT (P=0.047) before orthodontic treatment influenced the alteration of PH. With respect to the alteration of PBT, the diastema width (P=0.045) and PBT (P=0.000) were found to be influential factors. PBT before the orthodontic treatment significantly influenced the alteration of PBT in the multiple regression model. Conclusions: PH decreased but PBT increased after orthodontic closure of the diastema. The papilla dimensions before orthodontic treatment influenced the alterations of PH and PBT after closure of the diastema. The PBT increased more when the diastema width before the orthodontic treatment was larger.