SNL-EFDC를 이용한 군산항 유사퇴적고 계산의 비교 연구

이동주 ( Dong-joo Lee ),송상현 ( Sang-hyun Song ) 한국환경기술학회 2015 한국환경기술학회지 Vol.16 No.4

본 논문은 Ziegler, Lick, and Jones에 의해 개발된 SEDZLJ라 부르는 유사역학 알고리즘이 계산되는 SNL-EFDC 모델을 이용하여 군산항의 퇴적고 계산에 관하여 연구하였다. SEDZLJ모듈은 SEDflume 이나 Annular flumes로부터 얻은 현장 침식률 및 침식 한계전단응력 자료를 직접 결합할 필요가 있다. 군산항에서는 SEDflume 자료를 구할 수 없기 때문에 Ryu와 Yim에 의한 Annular flumes 실험으로부터 얻은 현장 침식률 및 침식 한계전단응력 자료를 이용하였다. SNL-EFDC 모델이 군산항의 유사퇴적고를 계산하기 위해 적용되었고 관측된 부유사 농도와 퇴적고를 사용하여 검증되었다. 유사 퇴적고 계산에 대한 모델의 적용성은 NSEC가 0.72로 침식과 퇴적의 물리적 변화가 적절하게 재현됨이 입증되었다. 부가적으로 검증된 모델은 저면 활성층두께에 대한 매개변수 α값의 영향을 조사하기 위해 사용되었고, Lee와 Park에 의해 수행된 SEDTM을 이용한 유사이동 계산의 결과와 비교하기 위해 사용되었다. 그 결과, 매개변수 α값의 변화는 유사퇴적고 계산에 미미한 영향이 미치는 것으로 나타났다. SEDZLJ에 의한 결과를 SEDTM의 것과 비교할 때 SEDZLJ모듈이 군산항에서 SEDTM 보다 NSEC가 0.03향상 되어 토사이송 과정을 재현함이 확인되었다. This paper was studied on the sediment deposition height computation at Gunsan port using recently advanced SNL-EFDC model which the sediment dynamics algorithm was called as SEDZLJ developed by Ziegler, Lick and Jones. SEDZLJ module needs to directly incorporate site-specific erosion rate and critical shear stress data from SEDflume or Annularflumes. Here this model attempted to use site-specific erosion rate and critical shear stress data from Annular flumes experiment by Ryu and Yim instead of unavailable SEDflume data at Gunsan port. SNL-EFDC was applicated to calculate deposition height at Gunsan port and verified using observed values for suspended sediment concentration and sediment deposition height. The model applicability for sediment deposition height computation was evaluated as NSEC 0.72 and verified that it reproduced the physical variations of erosion and deposition. In addition, the verified model was used to investigate the effect of parameter “α” on the active bed layer thickness and used to compare with the result of sediment transport computation using SEDTM done by Lee and Park. As a result, it was found that the change of parameter “α” value has a negligible effect on sediment deposition height computation. As results of SEDZLJ are compared with those of SEDTM, it was identified that SEDZLJ module reproduces the sediment transport process more appropriately than SEDTM at Gunsan port with advanced NSEC 0.03.

지중 열교환기용 시멘트 그라우트에 관한 연구

이동주,백환조,김경만,Lee, Dong-Ju,Baek, Hwan-Jo,Kim, Gyoung-Man 강원대학교 산업기술연구소 2011 産業技術硏究 Vol.31 No.2

In this paper, the applicability of cement grout has been studied as an alternative to bentonite grout for backfill ground heat exchangers. To provide an optimal mixture design, the thermal conductivity of cement grout and bentonite grout with various mixture ratios were experimentally evaluated and compared. Numerical analyses using Fluent(FVM program) were applied to compare the thermal transfer efficiency of the cement grout with that of the bentonite grout used in the construction. Also the effective ground thermal conductivity was measured by In-situ thermal response test. The results showed that the thermal efficiency of the cement grout was better than the bentonite grout. Consequently, the cement grout could be an alternative with more thermal efficiency to bentonite grout for ground heat exchangers.

밀리미터파 추적 레이더용 전원공급기 개발

이동주,최진규,주지한,권준범,변영진,Lee, Dongju,Choi, Jinkyu,Joo, Ji-Han,Kwon, Jun-Beom,Byun, Young-Jin 한국인터넷방송통신학회 2021 한국인터넷방송통신학회 논문지 Vol.21 No.4

밀리미터파 추적 레이더는 다양한 환경조건에서 운용 가능해야하므로 기존의 추적 레이더에 비해 동등 이상의 연산능력 및 소형화를 요구한다. 본 논문에서는 밀리미터파 추적 레이더에 적용하기 위한 소형 전원공급기 설계 및 구현방안에 대해 기술한다. FPGA/DSP 등 디지털회로의 저전압/고전류 및 전압 정밀도 요구사항 충족을 위해 Point of Load (POL) 컨버터를 적용하였으며, 전력밀도를 향상시키고 시스템 효율을 개선할 수 있다. 부하가 크지 않은 출력전압에는 LDO (Low Dropout) 등을 적용하여 최대 출력 375 W, 출력 전원 8종의 단일 입력-다중 출력 전원공급기를 개발하였다. 최대 부하 조건에서 전압정밀도 <±2 %, 잡음레벨 <50 mVpp 특성을 확인하였다. Millimeter-wave tracking radars should be operated in various environmental restrictions, thus they demand more computing power and smaller size compared to conventional tracking radars. This paper presents the design and implementation of the compact power supply for millimeter-wave tracking radar applications. To meet requirements of low voltage/high current and voltage accuracy for FPGA/DSP digital circuits, Point of Load (POL) converters are used in order to enhance power density and system efficiency. LDO (Low Dropout) is applied for the output voltage under the light load condition, then the single-input-multi-output power supply with max power of 375 W and 8 outputs is developed. The proposed power supply achieves output voltage accuracy of ±2 % and noise level of <50 mVpp % under full load conditions.

고속압밀법에 의해 제작된 유리섬유강화 PET 기지 복합재료의 최적제작조건

이동주,신익재,김홍건,Lee, Dong-Ju,Sin, Ik-Jae,Kim, Hong-Geon 대한기계학회 2002 大韓機械學會論文集A Vol.26 No.5

Glass fiber reinforced PET matrix composite was manufactured by rapid press consolidation technique as functions of temperature, pressure and time in pre-heating, consolidation and solidification stages. The optimal manufacturing conditions for this composite were discussed based on the void content, tensile, interlaminar shear and impact properties. In addition, the levels of crystallinity with various manufacturing conditions were measured using differential scanning calorimetry to investigate the mechanical properties of this composite material as a function of crystallinity. Among many processing parameters, the mold temperature and the cooling rate after forming were found to be the most critical factors in determining the level of crystallinity and mechanical properties. The level of crystallinity affects the tensile properties to some degree. However, impact properties are affected much more. It also affects the degree of ductility, which determines the impact energy of this material.

Studies on the Anionic Copolymerization of Isocyanates

이동주,Lee, Dong-Choo Korean Chemical Society 1973 대한화학회지 Vol.17 No.5

DMF 및 NaCN 존재하에서 p-tolylisocyanate와 n-hexylisocyanate의 저온 음이온 공중합을 시도하였다. 고웅합체의 분자량 및 구조확인은 각각 삼투압 법과 적외선법에 의하였다. 공중합체 조성분석도 적외선법에 의하였다. 이 공중합체의 공중합 경향은 $M_2$의 반응성이 훨씬 큰 것으로 나타났고 따라서 비 이상형 공중합이었다. 동 mole의 단량체에 의하여 얻어진 공중합체는 rigid한 성질을 나타냈다. The low temperature anionic copolymerization of p-tolylisocyanate ($M_1$) with n-hexylisocyanate ($M_2$) in DMF was carried out with NaCN. Copolymers were characterized by osmometry and I. R. spectrophotometry. Also copolymer composition was analyzed by spectral measurements. The behavior of this copolymerization system was the type of less ideal, that is the $M_2$ prefers to react exclusively with the same kind of species. The stress-strain behavior of the copolymer obtained from equimolar comonomer feed exhibited somewhat brittle or rigid character.

Factors Influencing Learning Satisfaction of Migrant Workers in Korea with E-learning-Based Occupational Safety and Health Education

이동주,Young Joo Lee 한국산업안전보건공단 산업안전보건연구원 2015 Safety and health at work Vol.6 No.3

Background: E-learning-based programs have recently been introduced to the occupational safety and health (OSH) education for migrant workers in Korea. The purpose of this study was to investigate how the factors related to migrant workers’ backgrounds and the instructional design affect the migrant workers’ satisfaction with e-learning-based OSH education. Methods: The data were collected from the surveys of 300 migrant workers who had participated in an OSH education program. Independent sample t test and one-way analysis of variance were conducted to examine differences in the degree of learning satisfaction using background variables. In addition, correlation analysis and multiple regression analysis were conducted to examine relationships between the instructional design variables and the degree of learning satisfaction. Results: There was no significant difference in the degree of learning satisfaction by gender, age, level of education, number of employees, or type of occupation, except for nationality. Among the instructional design variables, “learning content” (b ¼ 0.344, p < 0.001) affected the degree of learning satisfaction most significantly, followed by “motivation to learn” (b ¼ 0.293, p < 0.001), “interactions with learners and instructors” (b ¼ 0.149, p < 0.01), and “previous experience related to e-learning” (b ¼ 0.095, p < 0.05). “Learning environment” had no significant influence on the degree of learning satisfaction. Conclusion: E-learning-based OSH education for migrant workers may be an effective way to increase their safety knowledge and behavior if the accuracy, credibility, and novelty of learning content; strategies to promote learners’ motivation to learn; and interactions with learners and instructors are systematically applied during the development and implementation of e-learning programs.

미국(美國)의 고분자공업(高分子工業)

이동주,Lee, Dong-Ju 韓國고무學會 1966 엘라스토머 및 콤포지트 Vol. No.

클린 디젤엔진용 워터펌프 유동해석

이동주,김태영,전문수,Lee, Dongju,Kim, Taeyoung,Chon, Mun Soo 한국교통대학교 융복합기술연구소 2014 융ㆍ복합기술연구소 논문집 Vol.4 No.2

Pressure distribution around rotating impeller blades in centrifugal pump has been main issue for design of efficient and high performance automotive water pump. In addition, pressure losses of inlet water pipes should be considered to reduce additional pressure drop and design high performance engine cooling system. In this paper, pressure distribution inside water pump and pressure drop between inlet and outlet of water pump are investigated numerically to design plastic water pump for clean diesel engine application. And the inlet geometry of water pump was considered to analysis the effect of inlet water pipe geometry on pressure distribution around impeller blades and outlet pressure. The prediction results are compared with experimental data to validate and determine optimal operation condition without water pump cavitation. Major design parameters such as blade angle, volute geometry, system pressure, and coolant flow rate are considered to confirm applying possibility of plastic blades to the clean diesel engine.

Butyl 고무에 관(關)하여

이동주,Lee, Dong-Ju 韓國고무學會 1968 엘라스토머 및 콤포지트 Vol. No.

Hellman 치령(齒齡) IVA 정상인(正常人)에 관(關)한 두부방사선학적(頭部放射線學的) 연구(硏究)

이동주,Lee, Dong Joo 대한치과교정학회 1979 대한치과교정학회지 Vol.9 No.1

This study was undertaken to establish the cephalometric standard of Hellman dental age IVA group of Korean. The subjects consisted of 40 males and 44 females with normal occlusion and aceptable profile. The results were obtained. 1) The tables of standard deviation from the measurements were made. 2) All linear measurement was greater in male than in female. 3) Female had more convex profile than male, 4) Facial convexity, upper and lower lip of esthetic line were gradually decreased with. age. 5) Upper incisor was gradually labioversioned with age.