콘크리트 압축강도와 염화물 확산의 상관성 평가에 대한 연구

이학수,이승훈,권성준 청운대학교 건설환경연구소 2013 청운대학교 건설환경연구소 논문집 Vol.8 No.1

Compressive strength in concrete is a representative evaluation index for safety and durability performance. This paper is for evaluating a correlation between accelerated/apparent chloride diffusion coefficients which are time-dependant and compressive strength at the age of 28days(standard) and 270days(long term). For this work, seven mix cases with three different w/b(water to binder ratio) ratios for concrete are prepared. GGBFS(Ground Granulated Blast Furnace Slag) and FA(Fly Ash) are considered as mineral admixtures. Compressive strength and accelerated/apparent chloride diffusion coefficients are obtained and their correlations are investigated. Finally relationships between compressive strength and diffusion coefficients are derived through non-linear regression analysis. The suggested relationships with reasonable correlation can be used for chloride penetration evaluation. 콘크리트 압축강도는 콘크리트의 구조적, 내구적 성능을 평가할 수 있는 대표적인 지표이다. 본 연구에는 재령 28일(표준), 270일(장기)의 압축강도를 이용하여 재령별 변화하는 촉진 염화물 확산계수 및 겉보기 염화물 확산계수와의 상관성을 평가하는 것이다. 이를 위해 3가지 물-결합재비를 가지는 7가지 콘크리트 배합이 준비되었으며, 혼화재료로서 고로슬래그미분말, 플라이애쉬가 사용되었다. 실험을 통하여 압축강도와 촉진/겉보기 염화물 확산계수가 분석되었으며, 압축강도를 이용하여 염화물 확산계수를 평가할 수 있는 비선형 회귀분석식을 제안하였다. 제안된 식은 실험값(촉진/겉보기 염화물 확산계수)과 신뢰할만한 상관성을 가지고 있으며, 염화물 해석에 사용될 수 있다고 판단된다.

잊혀진 전쟁, 버려진 병사 : 부산 유엔공원의 6.25전쟁 기념을 중심으로

이학수 서울행정학회 2010 서울행정학회 학술대회 발표논문집 Vol.2010 No.1

재활용 팔라듐을 활용한 팔라듐 촉매 제조 공정기술 개발

이학수,신태섭,이지형,조남준 한국분석과학회 2023 한국분석과학회 학술대회 Vol.2023 No.5

경제외적 요인이 수산물 교역에 미치는 영향 : 노르웨이의 양식연어를 중심으

이학수,신용민 한국해양비즈니스학회 2021 해양비즈니스 Vol.- No.50

Export crises faced by Norwegian farmed salmon companies occurred due to a hygienic failure and international political issues rather than the internal structure of the Norwegian aquaculture industry. The first crisis occurred in 2010 when it was reported in media reports and research papers that pesticides were found in Norwegian farmed salmon. The European Union (EU) warned consumers in the EU member states of the danger of Norwegian farmed salmon, taking a toll on the Norwegian salmon export. In 2010, the Norwegian Nobel Committee selected a Chinese dissident as the winner of Nobel Peace Prize and China banned the import of Norwegian salmon in retaliation. In 2014 when the EU and the US imposed sanctions on Russia for its forced annexation of Crimea, Norway joined the sanctions although it was not an EU member state. Russia banned the import of Norwegian salmon in retaliation. International trade does not work only by a simple market logic. International politics and social issues intervene in international trade when trade items are related to the environment, resources, and hygiene. Norway paid a heavy price due to the intervention of those non-economic factors when exporting salmon, one of its main trade items. Paradoxically, as a result of the efforts made to remove the export restrictions, Norway obtained opportunities to enhance the competitiveness of its salmon industry in the global market.

Radiation-induced change after Gamma Knife radiosurgery for cerebral arteriovenous malformations

이학수,김해유,이선일,우준범,진성철,김무성 대한정위기능신경외과학회 2023 대한정위기능신경외과학회지 Vol.19 No.1

ObjectiveRadiation-induced change (RIC) on magnetic resonance imaging after Gamma Knife radiosurgery (GKRS) for cerebral arteriovenous malformations (AVMs) is not rare. We reviewed patients who underwent GKRS for AVMs and analyzed the results and factors associated with RIC. MethodsWe reviewed 189 patients who underwent GKRS for AVMs between October 2002 and August 2017. All patients were followed up for at least 3 years. This study included 111 males and 78 females (mean age, 39.63 years; range, 3-79 years). Nineteen patients underwent pre-GKRS embolization. Seventy-six patients had ruptured AVMs and 113 had unruptured AVMs. We analyzed obliteration and RIC occurrence rates. Several demographic and clinical factors were analyzed to determine the influence of AVM obliteration on RIC occurrence. ResultsThe overall obliteration rate (OR) was 72.49% (137/189) at the final follow-up. The actuarial OR was 55.5% 36 months after GKRS. The overall RIC occurrence rate was 28.04% (53/189), and the actuarial RIC occurrence rate was 26.8% 24 months after GKRS. The OR showed a statistically significant difference according to AVM rupture (p<0.01) and sex (p<0.01). The RIC occurrence rate was significantly associated with AVM rupture (p<0.01), lesion volume (p=0.04), and treatment volume (p=0.03). Other factors showed statistically non-significant relationships. ConclusionThe overall OR after GKRS for AVMs was comparable to the results of other previous reports. RIC is a common postoperative outcome following GKRS for AVMs. In this study, the OR was higher in ruptured AVMs and male patients, whereas RIC occurred more frequently in larger and unruptured AVMs. KEY WORDS: Radiation, Radiosurgery, Arteriovenous malformations

한국정부의 지방행정조직과 관리분석

李學守 대구효성가톨릭대학교 1996 연구논문집 Vol.53 No.1

In this study organizational structure and adminstrative agencies of local government in Korea are reviewed as a theoretical and empirical survey to see organizational analysis in governmental management. This paper is composed of following chapters. Chapter one is a step on a preface which defines ovjects and method of this study, and chapter two is a step on theoretical analysis and framework of local governmental organizations. Chapter three is a step on empirical basis of organizations, agencies and managment in local government, and chapter four is a conclusion about this paper. The ultimate findings are the follows, that is, that it is important to study between administrative areas and hierarchied in organizational side. And the above results directly have been influesced the composition and managment of administrative agencies in local government. Especially this will be a framework to analyze local organizations and management in Korean government.

Chiral Amine-induced Toroidal Structures of a Carboxylic Acid-functionalized Macrocyclic Diacetylene

이학수,김종만 한국고분자학회 2024 한국고분자학회 학술대회 연구논문 초록집 Vol.49 No.1

지방자치와 행정에서 갈등유형과 해결전략분석 : 최근 우리 나라 사례를 중심으로

이학수 대구효성가톨릭대학교 1997 연구논문집 Vol.56 No.1

This is the study concerning with the connection between conflict patterns and conflict bodies and items to cause the conflict. And this study searches for the good alternatives to develop local govermment. Therefore I analyze the following points here. ① definitions and characteristics of the administrative conflict ② causes and patterns of the conflict ③ strategies to settle the conflict ④ case study ; analysis and findings of data ⑤ evaluation and conclusion This study is composed of four chapters. Chapter one is the preface with the issues and methods for analysis, and chapter two is the framework for this study . Chapter three is about case study of recent data in Korean local govermment, and then chapter four is the conclusion and proposals. Above all the ultinate findings are that avoiding confilict diring some periods in Korea is very difficult, and that I think, there is no paradigmatic strategies to the conflict resolution, but for settling conflict we have to do them rationally, efficiently and democratically. At last I want to come up with the follow ideas ① strength of functions to conference among local authorities ② application with successful case study ③ search of various ways to minimize the conflict ④ comparative analysis of developed institutions and theories abroad ⑤ making of special agency to settle the conflict

구조 계획과 풍하중

이학수,김종락(Jong Rak Kim) 한국강구조학회 1992 한국강구조학회지 Vol.4 No.2

균열부 콘크리트에서의 탄산화 속도에 대한 실험적 연구

이학수,권성준 청운대학교 건설환경연구소 2012 청운대학교 건설환경연구소 논문집 Vol.7 No.1

In this study, concrete specimens with three different w/c(water to cement) ratios are prepared and cracks are induced in the specimens through splitting test after 28days curing. Each specimen is classified in the division of 0.1mm crack width, and carbonation depth in cracked and sound concrete are evaluated after accelerated carbonation test for 3 months. Through the experimental results, the relationship of carbonation velocity between sound concrete and cracked concrete is evaluated in the function of crack width. Finally optimal prediction for carbonation depth in cracked concrete is derived through the multi-regression analysis with parameters like w/c and crack width. 본 연구에서는 3가지 물시멘트비를 가진 콘크리트 시편을 제작하였으며, 28일 양생후 쪼갬인장실험을 통해서 균열폭을 도입하였다. 각 시편들은 균열폭 0.1mm단위로 그룹화하였으며, 3개월간의 촉진탄산화 실험을 통해서 건전부 및 균열부의 탄산화 깊이를 측정하였다. 실험결과를 통하여, 균열부 탄산화 속도와 건전부 탄산화 속도의 관계를 균열폭의 함수로 제안하였으며, 최종적으로 물시멘트비와균열폭에 대한 다중회귀분석을 통하여 균열부 콘크리트에 적용할 수 있는 탄산화 예측식을 도출하였다.