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FR4 PCB면적과 Via-hole이 LED패키지에 미치는 열적 특성 분석
김성현,이세일,양종경,박대희,Kim, Sung-Hyun,Lee, Se-Il,Yang, Jong-Kyung,Park, Dae-Hee 한국전기전자재료학회 2011 전기전자재료학회논문지 Vol.24 No.3
In this study, the heat transfer capability have been improved by using via-holes in FR4 PCB, when the LED lighting is designed to solve the thermal problem. The thermal resistance and junction temperature were measured by changing the dimension of FR4 PCB and size of via hole. As a result, when the dimension was increased initially, the thermal resistance and junction temperature was decreased rapidly, the ones was stabilized after the dimension of 200 $[mm^2]$. Also, the light output was improved up to maximum 17% by formation of via-hole and expansion of dimension in FR4 PCB. Therefore, the thermal resistance and junction temperature could be improved by expansion of PCB dimension and configuration of via-hole ability.
국립공원 관리를 위한 해양생태계 장기 모니터링 프로그램의 발전 방향
이채린(Chae-Lin Lee),유재원(Jae-Won Yoo),정병관(Byungkwan Jeoung),김창수(Chang-Soo Kim),안동식(Dong-Sik Ahn),김성태(Sungtae Kim),성은주(Eun-Ju Sung),김성현(Sung-Hyun Kim),정수영(Su-Yeoung Jeong),박영석(Young-Seuk Park) 국립공원연구원 2021 국립공원연구지 Vol.12 No.2
생태계 변화의 모니터링은 효율적 생태계 관리를 위한 기초 정보 수집을 위해 중요한 과정이다. 많은 생태 현상과 그 과정은 오랜 시간에 걸쳐 진행되므로 국립공원의 지속적인 보전 및 효율적 관리를 위해 생태계 모니터링은 장기적으로 이루어질 필요가 있다. 본 연구는 국내외 장기 모니터링 프로그램 사례 분석을 통해 성공적인 장기 모니터링을 위한 방법으로써, 최적화된 모니터링 설계, 표준화된 운용방안 마련, 인적 자원 및 DATA 관리 체계 수립, 안정적인 재정 마련 및 후속지원 등을 제시하였다. 이를 바탕으로, 현재 10년 넘게 수행되고 있는 ‘HS호 유류유출 사고 해역 장기 모니터링 프로그램’의 발전 방향으로 적응형 모니터링 방식이 적용된 표준화된 프로토콜의 정립, QA/QC와 지속적인 자료 관리, 조사 항목의 연계성 강화 등의 구체적 방안을 제안한다. Monitoring ecosystem changes is an important process for collecting basic information for ecosystem management. Since many ecological phenomena and their processes take place over a long period of time, it is necessary to conduct long-term monitoring of ecosystems for the continuous conservation and efficient management of national parks. This study suggested an optimized monitoring design, standardized operation plan, human resource and data management system, stable financial preparation and follow-up support as methods for successful long-term monitoring through case analysis of domestic and foreign long-term monitoring programs. Based on this, it proposes specific measures such as establishing a standardized protocol with adaptive monitoring methods, continuous data management with QA/QC, and strengthening the linkage of investigation items in the development direction of the “HS oil spill accident long-term monitoring program” that has been conducted for more than a decade.
갈색거저리를 이용한 식사 섭취에 따른 영양 섭취 및 영양상태 변화 : 수술 후 환자를 대상으로
김성현 ( Seong Hyeon Kim ),손진영 ( Jin Young Shon ),박준성 ( Jun Sung Park ),김종원 ( Jong Won Kim ),강정현 ( Jung Hyun Kang ),윤은영 ( Eun Young Yun ),황재삼 ( Jae Sam Hwang ),김형미 ( Hyung Mi Kim ) 대한영양사협회 2016 대한영양사협회 학술지 Vol.22 No.4
The purpose of this study was to verify the validity of Mealworms as a hospital meal with increased nutrition density. We provided a meal for postoperative patients and conducted analysis of dietary intake and nutritional status of patients and assessment of acceptability of the meal. This study was carried out as a randomized control trial. Patients were supplied either a hospital meal using Mealworms (Experimental group) or a regular hospital meal (Control group). We investigated the administration amounts of parenteral nutrition (PN) and food intake of patients after surgery and measured anthropometry, body composition, and blood tests before surgery and at hospital discharge. We included 34 postoperative patients who were admitted to Gangnam Severance Hospital from March to September. In the groups of patients not supplied with PN, the experimental group (964.68±284.6 kcal, 38.82±12.9 g) had significantly higher dietary calorie and protein intake than the control group (666.62±153.7 kcal, 24.47±4.9 g)(P<0.05). Additionally in the group of patients not supplied with PN, the experimental group (1.37%) showed a significantly higher increase in fat free mass index than the control group (-3.46%)(P<0.05). In all subjects, calorie density and protein density were significantly higher in the experimental group (P<0.001), and acceptability of calorie (P=0.036) and protein (P=0.001) was also significantly higher in the experimental group. Therefore, the results of this study support the validity of the introduction of hospital meals using Mealworms.
김성현(Sung-Hyun, Kim),박종원(Jong-Won, Park),이기천(Gi-Chun Lee),김재훈(Jae-Hoon, Kim) 대한기계학회 2019 대한기계학회 춘추학술대회 Vol.2019 No.5
The Shear used as attachment for construction machinery, is a device for cutting H beam and steel using shear force. It is used as a selective work device for construction machine such as excavator and is used in cutting work such as scrap iron and H beam structure. It is a reality that requires reliability in the related industries. The method of testing the reliability of Shear is as follows: breaking force test, open width measurement test, arm operation test, turning operation test, low temperature test, high temperature test, humidity and water test, impact test, pressure test, turning life test, But there is no standard for Shear. As a new type of device, it has been difficult to secure the reliability of a product suitable for the actual condition, and the result of the life test has not ben a test capable of securing data for evaluating reliability. To solve the above problems. it is necessary to standardize the reliability evaluation standard of Shear used as a selective work device for a construction machine. Therefore, in order to improve the reliability of Shear, which plays an important role in the field of construction and earth – moving machinery in new marketability, this study has developed a reliability evaluation technique.
필드데이터를 활용한 진동해머 구조물의 수명예측에 관한 연구
김성현(Sung-Hyun Kim),장무성(Mu-Seong Chang),이규석(Kyu-Seok Lee),이성규(Sung-Kyu Lee),백민혁(Min-Hyuck Baek),박종원(Jong-Won Park) 대한기계학회 2018 대한기계학회 춘추학술대회 Vol.2018 No.12
The vibro-hammer is a construction machinery attachment system that uses vibration to install passive piles and H beams. At the work site, it is mounted on the excavator and driven by generating the vibration using the hydraulic flow rate discharged from the vehicle. Control works such as tilting, swinging, jawing, and loosening are accomplished by opening and closing the valve. As a research subject, domestic products of construction machinery are often used abroad and lead to overseas exports. Therefore, it is important to deal with failures in the field effectively. In this study, we tracked and investigated field failures for high reliability. Tracking-investigating of failures data and attempting to develop parts around main functions of the vibro-hammer are performed. Through this, major modules are classified and failure data of each module are obtained. The shape parameter and scale parameter of the field failure data are estimated by Weibull analysis. Especially, failure analysis was performed on high strength steel (POSTEN 80), used to make a middle bracket (structural material), which is a worn part when a failure occurs. Strain data is obtained from field tests to predict fatigue life. And we analyze the physical data with operation mode by using strain data and the “Rainflow counting” method. “Strain-life” prediction method is performed and this will be helpful as basic data for Prognostics and Health Management.