프리캐스트 콘크리트 세그먼트의 합성섬유 보강재 적용에 따른 구조적 성능 평가

이호성,김창용,이승원,김승준,이경진,Lee, Hoseong,Kim, Changyong,Lee, Sean S.,Kim, Seungjun,Lee, Kyeongjin 한국터널지하공간학회 2018 한국터널지하공간학회논문집 Vol.20 No.2

쉴드TBM 터널의 프리캐스트 콘크리트 세그먼트 라이닝의 보강재로 철근이 주로 사용되어 왔으나, 철근 보강량을 줄이기 위하여 섬유보강재를 적용하는 연구가 진행되어 오고 있다. 세계적으로 터널 시공성을 향상시키기 위하여 강섬유보강재를 적용한 연구와 시공이 진행되어 왔으나, 터널 라이닝 방수막에 대한 펀칭, 자체 부식에 의한 내구성 및 미관상의 문제로 인하여 이에 대한 적용이 국내에서는 미뤄지고 있는 실정이며, 이에 대한 대책으로 합성섬유가 강섬유의 대체제로 주목 받고 있다. 이 연구에서는 섬유(강섬유, 합성섬유) 보강재를 사용한 프리캐스트 콘크리트 세그먼트의 파괴시험을 통하여 성능을 분석하여 현장에서의 적용 가능성을 평가하였다. 그 결과 강섬유와 합성섬유의 조합이나 합성섬유의 혼입량에 따라 보조철근의 대체가 가능한 것으로 분석되었다. Steel bars have been widely used as the primary reinforcement for Precast Segmental Concrete Lining for TBM Tunnels. Previously, studies have been carried out to gauge the potential for steel fiber reinforcement to replace the use of steel bar reinforcements in the segmental lining to reduce the amount of the steel bar reinforcement. Steel fiber reinforcements have been investigated and widely applied to SFRC TBM linings to improve the constructability of SFRC TBM linings worldwide. However, the steel fiber reinforcement often caused punctures to the water membranes inside tunnel lining and had long-term durability deterioration issues caused by steel corrosion, as well as cosmetic problems. Therefore, this paper sought to gauge the potential of synthetic fiber reinforcements, which have proven to be very attractive substitutes for steel fiber reinforcements. This study analyzed the performance of both steel and synthetic fiber reinforcements in segmental linings and evaluated the applicability of the fiber reinforcements to the TBM Precast Concrete Segmental Linings of TBM tunnels. As a conclusion, this study demonstrates that the potential use of steel and synthetic fibers in various combination, can substitute the rebar reinforcement in the concrete mix for segmental concrete linings.

초소성 및 확산접합을 이용한 우주항공 부품 성형기술 개발

이호성,윤종훈,이영무,Lee, Ho-Sung,Yoon, Jong-Hoon,Yi, Yeong-Moo 한국군사과학기술학회 2005 한국군사과학기술학회지 Vol.8 No.3

In this paper, a near net shape technology using superplasticity and diffusion bonding characteristics was presented for application to various components of aircraft and missiles. Due to these special characteristics of some aerospace alloys, it is possible to produce complex components to shape very near final dimension with enhanced design freedom, reduced material usage, and overall saving of weight and cost. The high pressure vessel for a space launcher was fabricated with Ti-6Al-4V alloy by superplastic forming and diffusion bonding process and the failure characteristics are compared with conventionally fabricated vessel spin formed and TIG welded. The structural integrity of the superplastic forming and diffusion bonding process was successfully demonstrated.

항공우주용 재료의 품질평가

이호성,Lee, Ho-Seong 한국재료학회 1995 한국재료학회지 Vol.5 No.1

현재 계획중인 항공우주상업과 관련된 부품을 제조하여 생산하기 위해서는 사용된 재료가 설계요구조건에 적합한지가 평가되어야 한지만 국내에서는 항공기나 우주비행체를 개발한 경험이 없으므로 평가체제가 확립되어 있지 않다. 따라서 항공기 및 우주비행체의 내구성과 안전성확보에 필요한 재료의 인정방법을 정의할 필요가 있다. 본 기고에서는 항공우주 선진국에서 수행하고 있는 재료 및 가공공정의 합치성 결정에 필요한 특성시험을 고찰하고, 우주환경에 의한 재료특성 변화와 항고기용 복합재료 평가의 예를 제시하여, 국내의 항공우주용 재료 평가체제 확립의 기초가 되도록 하였다. In order to manufacture and produce the components to be used for developing aerospace products, it is essential to determine the conformity of material characteristics to the design requirements. However, since the Korean industry has no experience to develop aircraft and spacecraft, the national certification system has not been established. Hence, it is necessary to define the qualification methodology of material to establish the durability and the safety of aircraft and spacecraft. In this paper the characterization methodology which has been performed in aeronautically advanced countries for determination of conformity in materials and production process is reviewed. The change of material properties due to the space environment and the example of evaluation program of composites for the application of aircraft are presented. so that the foundation of evaluation system for aerospace materials can be initiated.

남한 예비교사의 북한 화학 교과서에 제시된 과학 용어 이해

이호성,노봉오,박현주,Lee, Ho-Sung,Ro, Bong-Oh,Park, HyunJu 대한화학회 2008 대한화학회지 Vol.52 No.6

Alkylation and Allylation of Lithium Arylborates Factors Affecting the Di/Mono Substitution Ratio$^\dag$

이호성,송양섭,이동두,Lee, Ho-Seong,Song, Yang-Sup,Lee, Dong-Doo Korean Chemical Society 1987 Bulletin of the Korean Chemical Society Vol.8 No.5

Alkylation and allylation of arylborates give mono(ipso) and/or di(ortho and ipso) substitution products. Those factors which promote polarization or ionization of alkylating agents favor di substitution. The ${\sigma}$-type(ipso) substitution reaction of arylborates involves direct interaction of the carbon-boron bonds rather than predissociation of arylborates into aryllithiums and boranes.

Takotsubo Cardiomyopathy Associated with Severe Hypocalcemia Secondary to Idiopathic Hypoparathyroidism

이호성,Se-Whan Lee,Young Kyu Jung,Ung Jeon,박상호,Seung Jin Lee,Won-Yong Sin,Dong-Kyu Jin 대한심장학회 2013 Korean Circulation Journal Vol.43 No.8

The etiology and pathophysiology of takotsubo cardiomyopathy have not yet been fully clarified. We report a case of takotsubo cardio -myopathy associated with severe hypocalcemia secondary to hypoparathyroidism. A 69-year-old woman presented with acute pulmonary edema caused by severe left ventricular dysfunction with apical ballooning compatible with takotsubo cardiomyopathy. Laboratory tests revealed severe hypocalcemia secondary to idiopathic hypoparathyroidism. Coronary angiography showed normal coronary artery func-tion. Her symptoms and signs of heart failure improved dramatically with the correction of hypocalcemia through calcium and calcitriol replacement.

우주항공 재료시스템 품질인증

이호성,Lee, Ho-Sung 항공우주시스템공학회 2007 항공우주시스템공학회지 Vol.1 No.2

Structural qualification plan (SQP) for aerospace vehicle is based on material certification methodology, which must be approved by certification authority. It is internationally required to use of statistically based material allowables to design aerospace vehicles with aerospace materials. In order to comply with this regulation, it is necessary to establish relatively large amount of database, which increases test costs and time. Recently NASA/FAA develop the new methodology which results in cost, time, and risk reduction, and satisfies the regulation at the same time. This paper summarizes the certification methodology of materials system as a part of structural qualification plan (SQP) of aerospace vehicles and also thermal management of the vehicle system, like thermal protection materials system and thermally conductive material system. Materials design allowable was determined using this method for a carbon/epoxy composite material.

복층터널 내부슬래브의 연결형식에 관한 수치해석적 연구

이호성,문현구,Lee, Ho-Seong,Moon, Hyun-Koo 한국터널지하공간학회 2016 한국터널지하공간학회논문집 Vol.18 No.5

본 연구에서는 쉴드 TBM에 의한 대심도 복층터널의 계획 시 세그먼트 라이닝의 거동을 주요 구조물인 내부 슬래브의 연결구조 형식에 따라 검토하였다. 복층터널의 내부슬래브와 세그먼트 라이닝 설계 요구조건을 정립하기 위하여 용도에 따라 내부 구조물의 형식을 정의하고, 터널 라이닝과 내부 슬래브의 연결구조를 비교하였다. 그리고 MIDAS Civil 2012 프로그램으로 빔-스프링 모델을 이용하여 수치해석을 수행하였다. 본 연구결과 중간슬래브 및 하부슬래브, 내부슬래브와 세그먼트 라이닝의 연결 형식 그리고 측압계수들은 복층터널 계획시 주요 설계사항임을 확인하였다. This study analyzed behavior of the segment lining considering connection type between inner-slab and segment lining for a double deck tunnel by Shield TBM. In order to establish the design requirements of inner-slab and segment lining in double deck tunnel, inner structure of double deck tunnel at each purpose was analyzed and compared connection type between inner-slab and segment lining. And analyses have been carried out through the beam-spring model by MIDAS Civil 2012. As a result of this study, inner-slab, connection type of between inner-slab and segment lining and Lateral earth pressure coefficients were analyzed to verify the significant design factors.

유도무기용 날개구동기의 동적 강성 측정을 위한 유압 구동장치의 토크제어 기법에 관한 연구

이호성,Lee, Ho-Sung 한국군사과학기술학회 2007 한국군사과학기술학회지 Vol.10 No.3

This paper presents a torque control method of a hydraulic actuation system for measuring the dynamic stiffness of missile fin actuators. We propose a new control technique called Dual Dynamic Torque Feedback Control(DDTFC), which improves the stability of the torque control system and enables fast tracking of torque command. The developed control scheme is derived from the physical understanding based on mathematical modelling and analysis. The dynamics of hydraulic torque control servo-system is unravelled via physics-based modelling and nonparametric system identification. In order to verify the effectiveness of the method, the experiment is carried out with a test equipment for measuring the dynamic stiffness. The experiment and simulation results show that DDTFC gives stability improvement.

Assessing cardiac irisin activities and their associations on coronary and endothelial activities to compare their recoveries from oxidative stress‑induced cardiac cell injury by Chunglijagam‑tang, a Korean herbal medicine for “Heart Governs Vessels”

이호성,이승훈,Sunoh Kwon,Chae Rim Lee,오달석 경희대학교 융합한의과학연구소 2019 Oriental Pharmacy and Experimental Medicine Vol.19 No.4

Involuntary cardiac pumping supplies oxygen and nutrients into coronary and peripheral arteries, which has been recognized as main dynamics of body. Among the molecules regarding cardiac dynamics, we aimed to investigate whether oxidative stress would induce the production of the exercise hormone and its levels could be regulated by herbal medicine, which represents “Heart Governs Vessels.” We searched MEDLINE for exercise hormone and screened titles and abstracts. The primary human myocardial, coronary arterial and peripheral cell lines were treated with hydrogen peroxide to mimic oxidative stress condition. Activity of irisin, an exercise hormone, was measured by ELISA assay. Expression of NADPH oxidase 2, an irisin’s putative target, was determined by immunoblot assay. Among the cardiovascular effects, we found that left ventricular systolic functions could be affected by several molecules, including irisin. In primary myocardial, coronary arterial and peripheral cell lines, irisin secretion and NADPH oxidase 2 expression was increased by 75 µM hydrogen peroxide. Interestingly, ChungliJagam-tang inhibited NOX2 activities by 31.45%, 42.62%, and 47.22% in an oxidative stress-induced primary myocardial, coronary arterial and peripheral cell lines, respectively. In conclusion, the changes in NOX2 level under an oxidative stress condition which mimicked left ventricular functions are associated with cardiac irisin activities and they were controlled by the herbal prescription on “Heart Governs Vessels”.