• Earthquakes and Structures
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• 제8권6호
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• pp.1363-1386
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• 2015

The October 23 2011 Van Earthquake is studied from an earthquake engineering point of view. Strong ground motion processing was performed to investigate features of the earthquake source, forward directivity effects during the rupture process as well as local site effects. Strong motion characteristics were investigated in terms of peak ground motion and spectral acceleration values. Directiviy effects were discussed in detail via elastic response spectra and wide band spectograms to see the high frequency energy distributions. Source parameters and slip distribution results of the earthquake which had been proposed by different researchers were summarized. Influence of the source parameters on structural response were shown by comparing elastic response spectra of Muradiye synthetic records which were performed by broadband strong motion simulations of the earthquake. It has been emphasized that characteristics of the earthquake rupture dynamics and their effects on structural design might be investigated from a multidisciplinary point of view. Seismotectonic calculations (e.g., slip pattern, rupture velocity) may be extended relating different engineering parameters (e.g., interstorey drifts, spectral accelerations) across different disciplines while using code based seismic design approaches. Current state of the art building codes still far from fully reflecting earthquake source related parameters into design rules. Some of those deficiencies and recent efforts to overcome these problems were also mentioned. Next generation ground motion prediction equations (GMPEs) may be incorporated with certain site categories for site effects. Likewise in the 2011 Van Earthquake, Reverse/Oblique earthquakes indicate that GMPEs need to be feasible to a wider range of magnitudes and distances in engineering practice. Due to the reverse faulting with large slip and dip angles, vertical displacements along with directivity and fault normal effects might significantly affect the engineering structures. Main reason of excessive damage in the town of Erciş can be attributed to these factors. Such effects should be considered in advance through the establishment of vertical design spectra and effects might be incorporated in the available GMPEs.

• The Journal of the Acoustical Society of Korea
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• 제14권2E호
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• pp.73-86
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• 1995

전향 초음파 영상 캐서터의 트랜스듀스 (FLUIC) 부분은 진동자인 원형 전기음향 소자와 원뿔꼴 반사체인 음향 반사체로 구성된다. 소형의 전기음향 소자는 캐서터의 회전자 축 측면에 탑재된다. 전향 초음파 영상 캐서터의 특징은 기존의 IVUS 트랜스듀서가 제공할 수 없는 캐서터 전단에서 혈관의 단층 2-D 영상과 종래의 측면 영상을 동시에 제공하는 것이다. FLUIC의 트랜스듀서에 사용된 음향 반사체를 설계하기 위해 근사화된 레이 추적 기법을 이용하였다. 음향 반사체로부터 2차 외절 특성을 예측하기 위해 회절전달함수방식에[1] 의한 1차 음원으로 부터의 장 예측모델을 확장하여 일반화 하였다. 확장된 모델은 단순한 평판 반사체에 적용하여 시뮬레이션과 실험에 의해 검증되었으며 FLUIC의 잘 특성을 해석하는데 사용되었다.

• 한국자원식물학회:학술대회논문집
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• 한국자원식물학회 2018년도 춘계학술발표회
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• pp.95-95
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• 2018

Uric acid is the end product of purine metabolism in human body, originating from hypoxanthine after enzyme catalysis by Xanthine oxidase (XOD). Hyperuricemia results as a result of either over-generation of uric acid or a reduction in its excretion. In silico modelling methods such as Absorption, Distribution, Metabolism, Excretion and Toxicity (ADMET) prediction, Autodock 4.2.6 program were used to study the potential inhibitory compounds of XOD. Also we investigated the inhibition of XOD activity by using the extracts of Dendropanax morbifera and Rubus coreanus Miq spectrophotometrically. According to ADMET data, several compounds from D. morbifera and R. coreanus plants, were found to be more potent in inhibiting the XOD activity than allopurinol. XOD inhibitory activity is evaluated by quantifying the formation of uric acid by measuring the absorbance at 290 m ($A_{290}$).D. morbifera extract inhibited XOD activity at $250{\mu}g/ml$, however the extracts from R. coreanus has inhibited XOD activity at $25{\mu}g/ml$. The major compound of R. coreanus, ellagic acid significantly increased the inhibition rate from $9{\mu}g/ml$ and showed a 71% suppression rate at $15{\mu}g/ml$. Finally, these results suggested a potential inhibitory activities of the extracts from D. morbifera and R. coreanus Miq, but further research is needed to validate to ensure their safe usage as drug.

• 대한전자공학회논문지TC
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• 제37권8호
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• pp.33-44
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• 2000

고전압 전류 특성의 낙뢰는 안테나를 통해 지상에 설치된 이동 통신 기지국으로 도입될 수 있으며, 이를 방지하기 위한 장치가 서지 어레스터이다. 본 논문에서는 서지 어레스터의 개념, 종류, 동작 원리, 설계 및 제작 등을 검토하고, 이를 기반으로 현재 국내외에서 이용되고 있는 이동 통신 서비스인 셀룰라, GSM 및 PCS 등과 차세대 이동 통신 서비스인 IMT-2000의 기지국에 적용 가능한 서지 어레스터들을 설계하였다. 초기 설계된 서지 어레스터들은 고주파 3차원 구조 시뮬레이터 상에서 특성 예측을 위한 컴퓨터 모의 실험과 서지 어레스터의 전자기적 특성 개선을 위한 내부 구조 최적화 작업이 수행되었다. 서지 어레스터의 최종 설계도를 기반으로 실제 IMT-2000 기지국용 4분의 1 파장 단락 스터브 방식의 서지 어레스터를 제작하였으며, 전자기적 전송 특성 측정과 낙뢰 전달 테스트를 수행하여 제작된 서지 어레스터의 성능을 측정하였다. 측정 결과, 전압 정재파 비는 1.05 이하, 삽입 손실은 -0.035 dB이하, 상호변조 특성은 -150 dBc 이하의 특성을 얻었으며, 잔여 전압 특성은 7∼ll V 정도의 특성을 보였다.

• 대한토목학회논문집
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• 제7권4호
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• pp.41-50
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• 1987

본(本) 연구(硏究)는 실제(實際) 매립지(埋立地)의 현장조사와 Lab-Lysimeter의 측정(測定)을 실시하여 침출수(浸出水)의 발생량(發生量)과 수질(水質)을 예측하기 위하여 수행되었다. 매립시간(埋立時間)의 경과에 따른 폐기물중(廢棄物中) 휘발성(揮發性) 고형물질(固形物質)(VS)의 함량(含量), 생분해가능물질(生分解可能物質)(biodegradable matter, BDM), 함수율(含水率)(moisture content), 수분저장능력(水分貯藏能力)(field capacity), 건조단위중량(乾燥單位重量)(dry density) 등(等)을 측정분석(測定分析)하여 매립지내(埋立地內)의 폐기물(廢棄物)의 성상(性狀) 및 분해(分解)정도를 파악하고, 매립지(埋立地)의 성상(城上)과 비슷한 Lab-Lysimeter를 제작하여 생폐기물(生廢棄物) 및 분해(分解)가 진행(進行)된 폐기물(廢棄物)을 투입하여 침출수(浸出水)의 발생량(發生量) 및 수질(水質)을 측정분석(測定分析)하였다. 또한 불포화(不飽和)흐름방정식(方程式)에 증발산량(蒸發散量)과 표면유출(表面流出)을 고려한 모델을 만들고, 분해요소(分解要素)를 적용하여 불포화분해이송식(不飽和分解移送式)으로 발전(發展)시켰으며, 유한차분법(有限差分法)(finite difference method)을 이용(利用)하여 computer program을 개발(開發)하였고 폐기물(廢棄物) 매립지(埋立地)에서 지수문학적(地水文學的) 요소(要素)와 폐기물(廢棄物)의 분해요소등(分解要素等)을 고려하여 simulation을 실시하였으며 실험결과(實驗結果)와 비교(比較) 검토(檢討)한 결과(結果), 본(本) 연구(硏究) 모델이 침출수(浸出水)의 발생량(發生量)과 수질(水質)을 예측하는데 적합하다고 판단되었다.

• Structural Engineering and Mechanics
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• 제39권2호
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• pp.241-266
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• 2011

The Self Compacting Concrete, SCC is the new generation type of concrete which is not needed to be compacted by vibrator and it will be compacted by its own weight. Since SCC is a new innovation and also the high strength self compacting concrete, HSSCC behavior is like a brittle material, therefore, understanding the strength effect on the serviceability performance of reinforced self compacting concretes is critical. For this aim, first the normal and high strength self compacting concrete, NSSCC and HSSCC was designed. Then, the serviceability performance of reinforced connections consisting of NSSCC and HSSCC were investigated. Twelve reinforced concrete connections (L = 3 m, b = 0.15 m, h = 0.3 m) were simulated, by this concretes, the maximum and minimum reinforcement ratios ${\rho}$ and ${\rho}^{\prime}$ (percentage of tensile and compressive steel reinforcement) are in accordance with the provision of the ACI-05 for conventional RC structures. This study was limited to the case of bending without axial load, utilizing simple connections loaded at mid span through a stub (b = 0.15 m, h = 0.3 m, L = 0.3 m) to simulate a beam-column connection. During the test, concrete and steel strains, deflections and crack widths were measured at different locations along each member. Based on the experimental readings and observations, the cracked moment of inertia ($I_{cr}$) of members was determined and the results were compared with some selective theoretical methods. Also, the flexural crack widths of the members were measured and the applicability for conventional vibrated concrete, as for ACI, BS and CSA code, was verified for SCCs members tested. A comparison between two Codes (ACI and CSA) for the theoretical values cracking moment is indicate that, irrespective of the concrete strength, for the specimens reported, the prediction values of two codes are almost equale. The experimental cracked moment of inertia $(I_{cr})_{\exp}$ is lower than its theoretical $(I_{cr})_{th}$ values, and therefore theoretically it is overestimated. Also, a general conclusion is that, by increasing the percentage of ${\rho}$, the value of $I_{cr}$ is increased.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2008년도 추계학술대회B
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• pp.3049-3052
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• 2008

MCFC(molten carbonate fuel cell) power generation system is prime candidate for the utilization of fossil based fuels to generate ultra clean power with a high efficiency. In the MCFC power plant system, a combustor performs a role to supply high temperature mixture gases for cathode and heat for reformer by using the stack off-gas of the anode which includes a high concentration of $H_2O$ and $CO_2$. Since a combustor needs to be operated in a very lean condition and to avoid excessive local heating, catalytic combustor is usually used. The catalytic combustion is accomplished by the catalytic chemical reaction between fuel and oxidizer at catalyst surface, different from conventional combustion. In this study, a mathematical model for the prediction of internal flow and catalytic combustion characteristics in the catalytic combustor adopted in the MCFC power plant system is suggested by using the numerical methods. The numerical simulation models are then implemented into the commercial CFD code. After verifying result by comparing with the experimental data and calibrated kinetic parameters of catalytic combustion reaction, a numerical simulation is performed to investigate the variation of flow and combustion characteristics by changing such various parameters as inlet configuration and inlet temperature. The result show that the catalytic combustion can be effectively improved for most of the case by using the perforated plate and subsequent stable catalytic combustion is expected.

• 한국환경교육학회지:환경교육
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• 제20권1호
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• pp.42-61
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• 2007

This study investigated the effect of the environmental issue analysis instruction on the decision making ability of middle school students. A pretest-posttest control group design was employed. The participants for the research were 288 1st grade male students in middle school in Seoul, the environmental issue analysis lesson group consisted of 142 members and the non-environmental education group consisted of 146 members. The cognitive level of the students were divided into three groups-concrete, transition, formal-as the result of GALT test. Students take issue analysis lessons during 6 weeks, one lesson per a week. Students had studied through worksheets reconstructed and developed by researcher on basis of issue analysis suggested by Ramsey et al. (1997). The results of the research were followings: After lesson for environmental issue analysis, all of the students were improved in decision-making ability regardless of cognitive level (p<.05). Especially, decision-making ability of the transition group students was improved to a high degree. Scores of searching relevant information, generation of alternatives, identification of values for selection criteria, the evaluation of alternatives' merits and demerits, prediction of consequence were increased in experimental group (p<.05). But the ability of selection of alternatives according to value was not reached statistically meaningful improvement. The decision-making ability of the control group students was not improved but ability of selection of alternatives, the evaluation of consequence were increased (p<.05).

• 물과 미래
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• 제27권3호
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• pp.45-54
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• 1994

물수지 모델을 사용하여 발생시킨 시계열에 대해서 프랙탈(Fractal) 차원의 기본 이론이 소개 및 적용되었고 물수지 방정식이 넓은 지역에 대해 계절 시간 규모로 분석하였다. 중간 규모 순환의 발생과 변화에 있어 강우의 국부 재순환과 토양 수분의 동력학적 영향이 명시적으로 포함되어 있고 지체 시간 또한 분석에서 고려되었다. 시스템은 전개에 있어 변수 값들에 따라 고정점, 한계주기 그리고 카오스(Chaos)적인 행태와 같은 서로 다른 결과를 보여 주었다. 발생된 시계열의 추계학적인 행태는 궤적들이 초기 조거넹 매우 민감한 한정된 수의 방정식을 가지는 비선형 동력학 시스템으로부터 발생하는 확정론적 카오스 때문이다. 강우의 특성으로부터 발생하는 잡음은 어트랙터(Attractor)의 조직화된 구조를 파괴시키는데, 잡음의 존재에도 불구하고 어트랙터가 존재한다는 것은 시스템의 전개의 다기 예측에 있어 매우 중요하다고 할 수가 있다. 이러한 비선형 동력계가 가지고 있는 의미는 수문자료나 현상들의 해석과 모델링에 있어 중요하다.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 2004년도 추계 학술발표회 제16권2호
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• pp.409-412
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• 2004

Over last decade extensive researches have been undertaken on the strength behaviour of Fiber Reinforced Concrete(FRC) structures. But the use of Ultra-High Strength Steel Fiber Cementitious Concrete Composites is in its infancy and there is a few experiments, analysis method and design criteria on the structural elements constructed with this new generation material which compressive strength is over 150 MPa and characteristic behaviour on the failure status is ductile. The objective of this paper is to investigate and analyze the behaviour of reinforced rectangular structural members constructed with ultra high performance cementitious composites (UHPCC). This material is known as reactive powder concrete (RPC) mixed with domestic materials and its compressive strength is over 150MP. The variables of test specimens were shear span ratio, reinforcement ratio and fiber quantity. Even if there were no shear stirrups in test specimens, most influential variable to determine the failure mode between shear and flexural action was proved to be shear span ratio. The characteristics of ultra high-strength concrete is basically brittle, but due to the steel fiber reinforcement behaviour of this structure member became ductile after the peak load. As a result of the test, the stress block of compressive zone could be defined. The proposed analytical calculation of internal force capacity based by plastic analysis gave a good prediction for the shear and flexural strength of specimens. The numerical verification of the finite element model which constitutive law developed for Mode I fracture of fiber reinforced concrete correctly captured the overall behaviour of the specimens tested.