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A review of synthesis strategies for MOF-derived single atom catalysts
황종국 한국화학공학회 2021 Korean Journal of Chemical Engineering Vol.38 No.6
Single atom catalysts (SACs) have attracted great attention as promising catalysts that integrate the benefits of both heterogeneous and homogeneous catalysts. SACs exhibit unique properties that are otherwise difficult to achieve, such as high atom utilization efficiency, unprecedentedly high catalytic activity and selectivity. However, it still remains a great challenge to prepare stable SACs without particle aggregation and sintering. Among the various fabrication methods for SACs, metal-organic framework (MOF)-derived synthesis routes have shown great potential by taking advantage of MOFs’ high structural/chemical tunability, large surface area and high porosity. In this review, the synthesis strategies for MOF-derived SACs are comprehensively summarized and classified into five classes, metal node modification, ligand modification, guest encapsulation, migration and trapping, and others. The current challenges and future opportunities of MOF-derived SACs are further discussed. This review will be useful for the rational design of MOF-derived SACs for various catalytic reactions.
Resisting capacity of Korean traditional wooden structural systems subjected to static loading
황종국,Samuel Kwak,Ji-Hyun Kwak 국제구조공학회 2008 Structural Engineering and Mechanics, An Int'l Jou Vol.30 No.3
This paper investigates the structural behavior of Korean traditional wooden structures on the basis of the structural analysis using the commercialized program, SAP 2000. All the structural systems were analyzed, and the rotational stiffness at each joint was inferred from the experimental result for a half scale model of Bongjeong-sa (a temple in South Korea). In addition, the artificial control of analysis parameters was prevented because the structural analysis was focused on the realization of the most exact structural behavior of real structures. The analysis was carried out for the horizontal and vertical static loads, and all the secondary members were excluded in the structural analysis. The obtained results show that the resisting capacity of the primary structural system is greater than that of the expanding structural system.
황종국 한국풍공학회 2008 한국풍공학회지 Vol.12 No.2
The main objective of this paper is to investigate some questions regarding the dynamic characteristic of steeple in Korean stone pagoda. The steeple of Korean stone pagoda is composed usually stone ring and molded steel bar. Recent measurement data for weather have shown that the energy of typhoon are increased gradually. By this reason, the question has been raised as to the stability of stone pagoda. Especially, we must look more carefully into the vibration of steeple on stone pagoda. There has been no study that tried to figure out the vibration characteristic of steeple by wind. An one-sixth scale model is designed to perform wind tunnel test. For this model, we attempted force balance test. From force balance test, we figured out the vibration displacement of the top of steeple, maximum base shear, maximum overturning moment and wind force spectra. From force balance test, we figured out the maximum base shear of 6,800 N, the maximum overturning moment of 19,500 N-m. The analysis of spectra revealed that the magnitude of spectrum energy was not large and the unique phenomenon of spectrum energy was not figure out. So, one conclusion to draw is that the steeple of stone pagoda was safe for wind load. However, the vibration was caused by wind and the continuous vibration of steeple will show the decay of contact part. By this reason, it needs further consideration about the contact of steeple.
시멘트 벽돌 채움 전단벽 사용 신축 전통목구조물의 지진 응답에 관한 연구
황종국,권양희 대한건축학회 2020 대한건축학회논문집 Vol.36 No.10
This study was conducted with the aim of verifying the earthquake resistance capacity when cement bricks were used on divided traditionalwooden walls. The nonlinear spectral displacement was calculated to determine the seismic stability of new traditional houses. Spectraldisplacement response was calculated by applying the capacity spectrum. The new traditional houses were selected in two types, small andlarge, among the standard Gyeongsangbuk-do drawings. Capacity curves for each X and Y direction were obtained. The hysteresis curve wassimplified into two straight lines, divided into the initial elastic part and the fully plastic part. The table of resistance moment that can beused in the design of traditional wooden structures was calculated. The seismic resistance capacity analysis was performed. Response spectrafor seismic design were calculated in accordance with Korean Building Code and Commentary (KBC 2016). The effective ground accelerationand ground amplification factors were calculated according to the conditions applied to the traditional wooden structure based on small-scalestructural standard. In sample model, it was concluded that the drift ratio of 1.39% and 1.34% in the X direction were maintained. 본 연구는 시멘트 벽돌벽의 내력을 크기별로 확인한 후 조각된 전통목구조 벽체에 시멘트 벽돌이 사용되었을 때 지진에 대한 대응능력을 검증하고자 하는 목적으로 수행되었다. 새로운 전통주택의 내진 안정성을 판단하기 위해 발생 가능한 비선형 변위응답을 산출하였다. 변위응답은 능력스펙트럼법을 적용하여 산출하였다. 새로운 전통주택은 경북형 표준 도면 중 소형, 대형의 두 가지 형식을 선택하였다. X, Y 방향별 능력곡선은 사용된 전통벽체 유형에 대해서 각 유형별로 능력곡선을 구하고 방향별로 합성하여 구하였다. 이력곡선은 초기 탄성구간과 완전 소성구간으로 구분되는 두 개의 직선으로 단순화 하였다. 전통목구조 설계에 사용할 수 있는 저항모멘트 표를 산출하였다. 지진저항능력 분석은 표준화 도면을 대상으로 수행하였다. 지진 설계용 응답스펙트럼은 건축구조기준및해설(KBC 2016)에 따라 산출하였다. 유효지반가속도와 지반증폭계수는 소규모구조기준 전통목구조에서 적용하고 있는 조건에 따라 산출하였다. 소형, 대형 예제에서 X 방향의 경우 1.39%의 변위비와 1.34%의 변위비를 나타내었다.