여름느타리버섯 재배의 문제점

이지웅 충남대학교 농과대학 1996 논문집 Vol.- No.2

배출권 가격설정 모형 연구 최신 현황과 시사점

이지웅,이상림 에너지경제연구원 2013 에너지경제연구원 수시연구보고서 Vol.- No.-

선박용 발전기 엔진 출력 측정 장치의 TDC 오차 발생 원인

이지웅,정균식,이원주 해양환경안전학회 2020 海洋環境安全學會誌 Vol.26 No.4

Different methods are used for determining the output of engines to obtain the indicated horsepower by measuring the combustion pressure of cylinders, and to obtain the shaft horsepower by measuring the shaft torque. It is difficult to examine the shaft torque using the condition of the cylinder, and the most accurate method used for determining the combustion pressure involves examining the combustion state of the cylinder to evaluate the engine performance and analyze the combustion of the cylinder. During the measurement, the combustion pressure is the most important parameter used for accurately determining the cylinder angle because the cylinder pressure is indicated based on the angle of the crankshaft. In this study, an encoder was used as the crank angle sensor to measure the cylinder pressure on the generator engine of the actual operating ship. The reasons for the differences between the top dead center (TDC) recognized by the encoder (TDC_encoder) and the TDC recognized by the compression pressure (TDC_comp) were considered. The differences between the TDCcomp and TDCencoder of the cylinders measured at idle running, 25%, 50%, and 60% loads were analyzed to determine for the crankshaft production effect, the crankshaft torsion effect owing to the increased rotational resistance from the increased load, and the coupling damping effect between the engine and generator. It was confirmed that the TDC error occurred up to 3° crank angle as the load of the generator increased. 엔진의 출력을 측정하기 위한 방법은 실린더의 연소압력을 측정하여 지시마력을 구하는 방법과 축토크를 측정하여 축마력을 구하는 방법이 있다. 축토크로 실린더의 상태를 확인하기에는 한계가 있으며, 엔진의 성능 측정과 실린더의 연소 해석을 위해서는 실린더의 연소 상태를 확인할 수 있는 연소압력을 측정하는 방법이 가장 정확하다. 측정에 있어 연소압력은 크랭크샤프트 회전 각도에 따른 실린더 압력이 도시되어야하기 때문에 정확한 실린더 앵글각도를 정확히 인지시키는 작업이 가장 중요하다. 본 연구에서는 실제 운항선의 발전기 엔진을 대상으로 실린더 압력을 측정하기 위하여 크랭크 앵글 센서로 엔코더를 사용하였고 엔코더에서 인지하는 TDC(TDC_encoder)와 압축압력에 의한 TDC(TDC_comp) 간의 실측을 통하여 차이가 발생하는 원인에 대하여 고찰하였다. 또한 0%, 25%, 50%와 60% 부하에서 측정된 실린더의 TDC_comp와 TDC_encoder 간의 차이를 통하여 크랭크샤프트의 제작에 의한 영향, 부하증가에 따른 엔진과 발전기 사이의 커플링 영향에 대한 결과를 고찰하였으며, 발전기의 부하가 증가할수록 최대 3°CA까지 TDC의 오차가 발생함을 확인하였다.

[이지웅의 성공하는 미국 부동산 투자 ① 텍사스 오스틴] 제2의 실리콘 밸리로 우뚝 선다

이지웅 (주)매일경제신문사 2023 매경럭스맨 Vol.- No.158

5축 절삭가공기 교육 중 2NC 헤드의 고강도 알루미늄을 적용한스핀들 하우징의 극한 조건의 진동해석에 관한 연구

이지웅 한국실천공학교육학회 2022 실천공학교육논문지 Vol.14 No.1

Materials used for education are materials such as SM20C, Al6061, and acrylic. SM20C materials are carbon steel and are oftenused in certification tests and functional competitions, but are also widely used in industrial sites. The Al6061 material is said to bea material that has lower hardness and stronger flexibility than carbon steel, so it is a material that generates a lot of compositionalselection of tools. If students are taught practical training using acrylic materials, vibration occurs due to excessive cutting in someparts and damage to the tool occurs. In this process, we examine to what extent the impact on the 2NC head, which is a five-axisequipment, can affect precision control. The weakest part of the five-axis equipment can be said to be the weakest part of the headthat controls the AC axis. When the accuracy and cumulative tolerance of this part occur, the accuracy of all products decreases. Therefore, the core part of the 2NC head, the spindle housing, was carried out using an Al7075 T6 (Alcoa, USA) material. In the process of vibration and cutting applied to this material, the analysis was conducted to find out the value applied to the finite elementanalysis under extreme conditions. It is hoped that this analysis data will help students see and understand the structure of 5-axismachining rather than 5-axis cutting. 교육용으로사용되는피삭재(소재)는SM20C,Al6061,아크릴등의소재를사용한다. SM20C 소재는탄소강으로서자격증시험및기능경기대회에서많이사용되지만산업현장에서도많이사용된다. Al6061 소재는탄소강에비하여경도가낮아지고전성(연성)이강한소재이기에공구의구성인선이많이발생하는소재라고한다.아크릴소재를이용하여학생들에게실습지도하면어느부분에서과다절삭으로인하여진동이발생하고공구의파손이발생하는소재이다.이러한과정에서5축장비인2NC헤드에게가해지는충격이정밀도제어에는어느정도영향을줄수있는지알아본다. 5축장비의가장취약한부분은AC축을제어하는헤드가가장약한부분이라할수있다.이부분의정밀도및누적공차가발생할경우모든제품의정밀도가떨어지는현상이발생한다.따라서 2NC헤드의 핵심적인 부분, 스핀들 하우징은 Al7075 T6(미국 알코아사) 소재를 사용하여 진행하였다. 이 소재에서 작용되는진동및절삭과정에서힘을극한조건에서유한요소해석으로적용되는값을밝혀내고자해석을진행하였다.이러한해석데이터를활용하여학생들이5축절삭보다5축가공기의구조를보고이해하는데도움이되기를기대한다.

신기후체제 하의 국제탄소시장에 관한 최신 논의 현황과 전망

이지웅 에너지경제연구원 2016 에너지경제연구원 수시연구보고서 Vol.- No.-

한국인에 있어서 결절맥락막혈관병증의 역학과 임상소견

이지웅,김인택,Ji Woong Lee,In Taek Kim 대한안과학회 2007 대한안과학회지 Vol.48 No.1

Purpose: To investigate the incidence, demographic features and clinical characteristics of polypoidal choroidal vasculopathy (PCV) in Korean patients. Methods: We retrospectively reviewed the medical records of 413 patients (485 eyes) diagnosed with choroidal neovascularization in exudative age-related macular degeneration between June 2001 and September 2005. All patients underwent complete ophthalmologic examination, fluorescein and indocyanine green angiography, and optical coherence tomography. Results: Among a total of 485 eyes of 413 patients, 80 eyes of 66 patients (16.5%) were diagnosed with PCV. Men were predominantly affected (80.3%), and most patients were elderly with a mean age of 68.3 years (range, 50~93 years) and unilaterally involved (78.8%). The polypoidal lesions in PCV tended to be located in the macula area (62.5%). With respect to vascular network, fine vascular networks were observed in 51 eyes (63.7%) and large lesions were present in 16 eyes (20.0%). Clusters of grape-like polypoidal lesions (60%) were more common than solitary aneurysmal dilations (35.0%). Branching choroidal vessels were present in 67 eyes (83.7%) and absent in 13 eyes (16.3%). Optical coherence tomographic images of polypoidal lesions in 53 eyes showed uneven surfaces with more sharply peaked shapes different from those seen in the serous pigment epithelial detachment in age-related macular degeneration and central serous chorioretinopathy. Conclusions: The incidence of PCV in Korean patients was relatively high among various ethnic groups. Although the demographic and clinical features of PCV in Korea differed from Caucasian patients, they were similar to Japanese and Chinese patients.

연료 효율성 높은 자동차의 가격 프리미엄에 대한 연구

이지웅 에너지경제연구원 2015 에너지경제연구원 수시연구보고서 Vol.- No.-

In 2009, the previous Lee administration announced the Roadmap for Greenhouse Gas Emissions Reduction, which pledged the reduction target to cut emissions by 30% from the BAU level until 2020 and presented policies to meet the target. The feasibility of the reduction target had been under debate since its announcement. While there was the outlook that the reduction target might be abandoned or modified, in 2014 the current Park administration finally decided to succeed the target and continue the effort to cut carbon emissions as much as the target aims. According to the Roadmap, the sectoral reduction targets are, in descending, order as follows: transportation 34.3%, building 26.9%, power 26.7%, public 25.0%, industry 18.5%, waste 12.3% and agriculture·fishery 5.2%. It is worth noting that the reduction target of transportation is the most ambitious. But, the transportation sector is not included in the Korean Emissions Trading Scheme. Hence, in near future there will be a separate abatement policy aiming to the transportation sector. In order for any policy gearing up to reduce emissions in transportation to be effective, the information on how much citizens value the improvement of efficiency in their vehicles. Motivated by this necessity, this study conducts a hedonic regression to estimate the willingness-to-pay for one unit increase in car efficiency. We collect the sales data of 337 kinds of automobiles sold in 2013 in South Korea and divide them into two groups, one group for vehicles with price less than 50 million KRW and the other for vehicles with price between 50 million KRW and 100 million KRW. The results of regression show that consumers are willing to pay 350~400 thousand KRW for one unit (1km/L) efficiency improvement. Our study is the first one to estimate the willingness-to-pay for vehicle efficiency improvement in South Korea. The estimated willingness-to-pay will serve as a valuable input for policymakers. Still, our study also has several limitations. One of them is that our study does not consider the effect of the current low oil price trend.

탄소세를 기본소득으로? : 탄소세 도입을 둘러싼 쟁점들

이지웅 LAB2050 2021 LAB2050 연구보고서 Vol.- No.-

Operation Limit of Flow Control for a Bistable Fluidic Valve

이지웅,홍지석,성홍계 한국항공우주학회 2017 International Journal of Aeronautical and Space Sc Vol.18 No.3

The limitation of flow control for a bistable fluidic valve has been investigated. The physical model of the fluidic valve includes two main flow outlets and two control flow inlets. The experiments were conducted with pressure regulators, mass flow meters, and piezo sensors to analyze flow switching characteristics of the fluidic valve. The experimental data such as pressure and mass flow rate of control flows and the switching time of the main flow was obtained with various operating conditions. The operation limit of the fluidic valve is identified, and a model equation for pre-estimating the minimum control pressure to switch the direction of the main flow has been proposed.