황토모르타르의 압축강도 증진을 위한 실험적 연구

황원주 ( Hwang Won Ju ),김종우 ( Kim Jong Woo ),하상수 ( Ha Sang Su ) 한국구조물진단유지관리공학회 2018 한국구조물진단유지관리공학회 학술발표대회 논문집 Vol.22 No.2

The purpose of this experimental study is to increase the strength of mortar mixed with activated Hwang-Toh (AHT) and granulated blast furnace slag (GGBS) as a compound for the development of eco-friendly concrete. The compressive strength test was carried out by making mortar specimens with a certain ratio of AHT and GGBS. The percentage of AHT were at 30% and 50% and the GGBS were a 40% and 50% as Major variables. The results of this study showed that for specimens with percentage of AHT at 30% with GGBS increased above the strength of the mortar without the binding. However, the compressive strength of experimentation with percentage of AHT at 50% with partially replace GGBS has decreased by more than the mortar without the binding. Therefore, further study is deemed necessary.

에탄올-물 혼합용매내에서 2,4,6,N-Tetramethyl Pyridinium Iodide의 회합에 대한 압력효과

黃正儀,池鍾基,李永華,禹義夏 慶北大學校 物理化學硏究所 1984 硏究論文集 Vol.5 No.-

부피 퍼센트 95%의 에탄올-물 혼합용매내에서 2,4,6,N-테트라메틸 피리디늄요오드(TeMPI)의 이온회합 상수(K)를 수정한 자외선분광 및 전기 전도도 혼용법으로 온도범위 25∼50℃, 압력범위 1∼2,000bars에서 결정하였다. K값은 압력이 증가함에 따라서 증가하였고 40℃에서 최대값을 나타내었다. 부분몰부피변화(ΔV)는 비교적 작은 음의 값이 었으며 ΔV의 절대값은 40℃에서 최소값을 보여주었다. TeMPI의 이온 크기 변수(a)는 40℃에서 최대값을 가졌다. ΔH˚값은 40, 25℃ 그리고 50℃에서 각각 영, 음수 및 양수로 나타났으며 엔트로피(ΔS˚)와 자유에너지(ΔG˚)와 같은 다른 열역학변수 값도 계산하였다. 이와 같은 실험결과로부터 우리들은 TeMPI가 압력증가에 대하여 안정화되고, 40℃까지는 온도증가에 따라서도 안정화됨을 보여주었다. 그러나 40℃에서는 TeMPI 두 분자에 있는 8개 메틸기의 분자간 소수성 상호작용으로 인하여 약한 이량체를 형성하고 50℃ 이상에서는 다시 열적으로 분해된다는 결론을 얻게 되었다. The ionic association constants(K) of 2,4,6,N-tetramethyl pyridinium iodide(TeMPI) in 95 volume percentage ethanol-water mixture were determined by a modified UV and conductance method at 25℃ to 50℃ under 1 to 2,000 bars. The K values increase with increasing pressure and have maximum value at 40℃. The partial molar volume change (ΔV) has relatively small negative value and the absolute values of Δ are minimum at 40℃. The ion size parameter(a) of TeMPI have maximum value at 40℃. ΔH˚ values are zero, positive and negative at 40℃, 25℃ and 50℃ respectively. Other thermodynamic parameters such as the changes of standard entropy (ΔS˚) and free energy(ΔG˚) were evaluated. From these experimental results, we came to conclusion that TeMPI is stabilized by the elevation of pressure and that of temperature below 40℃ but weakly dimerized at 40℃ because of the intermolecular hydrophobic interaction of eight methyl groups of two molecules. And it thermally decomposed above 50℃.

원격구조모니터링시스템 개발을 위한 개념설계

황진하,박종희,정진덕,김주한 충북대학교 건설기술연구소 2003 建設技術論文集 Vol.22 No.2

A conceptual design for the development of a remote structural monitoring system is presented in this study. First of all, to satisfy the engineering and customer requirements, requirements/functional analysis for the remote structural monitoring systems are performed in context of the systems approach. The problem definition is given, And the market competitors are analyzed by benchmarking and the alternatives are evaluated. Based on the informations from the above stage, the key elements of the systems are extracted through the functional decomposition and the schematic specifications are described.

상시계측자료의 관리를 위한 테이터베이스의 원형 설계

황진하,박종희,조대현 충북대학교 건설기술연구소 2003 建設技術論文集 Vol.22 No.2

Prototype design of the database for ambient measurement data management is presented in this paper. To express the associated data generated during the whole process of ambient measurement efficiently, requirement/task analysis for database management system are peformed. And then to define and organize objects and schema for data model, conceptual and logical design are performed, which convert data model into logical schema. This prototype database is constructed by using via the object-relational data modelling approach.

해상 유류 유출 사고 후, 유류 해양 오염에 따른 주요 해산 어ㆍ패류내 PAHs 추적

황인영,박정규,박관하,김정상,정흥배,배철한 한국환경독성학회 2001 환경독성보건학회지 Vol.16 No.2

Marine organisms such as fish (Sebastes schlegeli) and mussels were cultured in sea water tanks placed at Dukpo area which was contaminated by the two oil spill accidents. Results showed that PAHs concentrations in fish tissue were higher than in fish liver. This was explained by the cytochrome P450 IA induction in fish liver after PAHs exposure. Other studies showed that higher PAHs levels were detected in mussels cultures in oil contaminated area than in control site. From these results, we concluded that Dukpo area is still polluted by oil including PAHs and it takes a long time to recover of oil contamination after the oil spill accidents.

다층인공신경망에 기초한 구조계 정정

황진하,박종회,김주한 충북대학교 건설기술연구소 2004 建設技術論文集 Vol.23 No.1

The structural system identification using neural networks is presented in this study. Among the neural networks, backpropagation neural network is adopted to fulfill the damage assessment. When the damages occur, the structural responses are changed and the responses contain the damage locations and extents. The static displacements of the truss structure are induced by the various damage states under the static load. In the neural networks the displaces are the inputs and the damage locations and extents are the outputs. The simulation informs that it is efficient to apply the neural network to the damage detection.

절삭공구 팁의 TiCN코팅 특성

황경층,윤종호,최재하,김성청 충북대학교 산업과학기술연구소 2002 산업과학기술연구 논문집 Vol.16 No.2

As the machine tool industry progresses, the performance of cutting tools also needs to be of good quality and specialized. If the existing metal cutting tool tip is coated properly, its life would be longer and the machining of a difficult-to-cut material also could be possible. For the development of the high quality cutting tool, the applicabilities of TiCN coating deposited by PVD on the cutting insert were experimentally investigated. The various analyses such as SEM micrograph, XRD pattern, AFM surface morphology, and hardness were performed to cross-check the possibility and availability of TiCN coated tool in the field.

설계조건 분할에 의한 다단계 구조최적화

황진하,박종회,정진덕 충북대학교 건설기술연구소 2002 建設技術論文集 Vol.21 No.1

A new method that performs multilevel design optimization for structural design is presented in this paper. This study demonstrates hybrid optimization method which combines a general mathematical programming algorithm with classical fully stressed design method. Systems optimization is achieved with system level constraints by the former, while the latter is exercised with local constraints in subsystem level. Numerical results for widely used truss models show the validity and efficiency of this study.

인코넬 690 합금의 절삭성에 관한 연구

황경충,윤종호,최재하,김성청 한국공작기계학회 2002 한국생산제조학회지 Vol.11 No.2

In domestic industry, there is no manufacturers specialized in the production of cutting tools for the difficult cutting materials. Then, we have few data about them. In this study, the gear driving high speed lathe on which is mounted by a tool dynamometer and high speed CCTV were used to measure the various machining characteristics. Relations among the cutting speed, feed rate per revolution, cutting depth, cutting forces and surface roughness were graphically analyzed under 64 cutting conditions. The process of chip, i.e., generation, development and falling-off also were visualized for the characterization of chip shapes of the difficult-to-cut materials using the CCTV.

인코넬 690 합금의 크리프거동

황경충,윤종호,최재하,김성청 한국공작기계학회 2002 한국생산제조학회지 Vol.11 No.4

Inconel 690 alloy has widely been used in power plant and high temperature facilities because it has high thermal resistance and toughness. But, we have little design data about the creep behaviors of the alloy. Therefore, in this study, an apparatus has been designed and built for conduction creep tests under constant load conditions. A series of creep tests on Inconel 690 alloy have been performed to get the basic design data and life prediction of inconel products and we have gotten the following results. First, the stress exponents decrease as the test temperatures increase. Secondly, the creep activation energy gradually decreases as the stresses becomes bigger. Thirdly, the constant of Larson-Moller parameters on this alloy is estimated about 10. And last, the fractographs at the creep rupture show both the ductile and the brittle fracture according to the creep conditions.