• Journal of the Korea institute for structural maintenance and inspection
• /
• v.7 no.3
• /
• pp.183-191
• /
• 2003

A four-story reinforced concrete moment resisting frame damaged from an ultimate limit state earthquake is upgraded with prestressing cable bracing. The purpose of this study is to investigate the bracing configuration effects on the 3-D building response using thee different locations of the bracing systems for the retrofitted building. Since the previous work done by the author proved that static incremental loads to collapse analysis as a substitute to dynamic non-linear time history analysis was a valid alternative tool. Thus, static load to collapse analysis is solely applied to evaluate the seismic performance parameters of both the original and upgraded buildings in this study. In results, the exterior bracing system is effective in restraining torsional behavior of the structure under seismic loads, and no sudden failure occurs in this system that enhances the ductility of the building due to the gradual change of building stiffness as the lateral load increases.

• Bulletin of the Society of Naval Architects of Korea
• /
• v.54 no.4
• /
• pp.39-46
• /
• 2017

Jack-up drilling rigs are widely used in offshore oil and gas exploration industry. It is originally designed for use in the shallow waters less than 60m of water depth; there is growing demand for their use in deeper water depth over 150m and harsher environmental conditions. In this study, global in-place analysis of jack-up rig leg for North-sea oil well is performed through numerical analysis. Firstly, environmental conditions and seabed characteristics at the North-sea are collected and investigated measurements from survey report. Based on these data, design specifications are established and the overall basic design is performed. Dynamic characteristics of the jack-up rig for North-sea are considered in the global in-place analysis both leg and hull and the basic stability against overturning moment is also analyzed. The structural integrity of the jack-up rig leg/hull is verified through the code checks and the adequate safety margin is observed. The uncertainty in jack-up behaviour is greatly influenced by the uncertainties in the soil characteristics that determine the resistance of the foundation to the forces imposed by the jack-up structure. Among the risks above mentioned, the punch-through during pre-loading is the most frequently encountered foundation problem for jack-up rigs. The objective of this paper is to clarify the detailed structure and installation engineering matters for prove the structural safety of jack-up rigs during operation. With this intention the following items are addressed; - Characteristics of structural behavior considering soil effect against environmental loads - Modes of failure and related pre-loading procedure and parameters - Typical results of structural engineering and verification by actual measurement.

• Journal of the Computational Structural Engineering Institute of Korea
• /
• v.30 no.3
• /
• pp.191-198
• /
• 2017

To study the behavior of structures subject to blast loads it is important to calculate the loads due to the explosives accurately, especially in the case of interior explosions. It is known that numerical method based on computational fluid dynamics can estimate relatively accurate blast load due to the interior explosion including reflection effect. However, the numerical method has disadvantages that it is difficult to model the analysis and it takes much time to analyze it. Therefore, in this study, the analytical method which can include the reflection effect of the interior explosion was studied. The target structures were set as the slabs of residential buildings subject to interior explosion that could lead to massive casualties and progressive collapses. First, the numerical method is used to investigate the interior explosion effect and the maximum deflection of the slab which was assumed to be elastic, and compared with the analytical method proposed in this study. In the proposed analytical method, we determine the weighting factor of the reflection effect using the beam theory so that the explosion load calculation method becomes more accurate.

• The Journal of Korean Academy of Prosthodontics
• /
• v.56 no.4
• /
• pp.302-307
• /
• 2018

Multiple tooth loss and excessive occlusal wear can result in damage to occlusal disharmony, functional disorders and esthetic problems, requiring comprehensive prosthetic treatments. Changing vertical dimension harmonized with surrounding muscle tissue is important. In this case, the patient with loss of vertical dimension caused by severe tooth loss and tooth wear was treated with the analysis of vertical dimension, such as diagnostic model, radiography and various clinical exams. the patient was satisfied with favorable functions and esthetics for 1 years of follow-up.

• Proceedings of the Korea Water Resources Association Conference
• /
• 2006.05a
• /
• pp.562-566
• /
• 2006

최근 들어 국내에서는 도서지방을 잇는 연육교와 해상구간을 통과하는 대형교량의 건설이 활발히 진행되면서 해상조건에서 발생하는 교량세굴에 대처하기 위한 연구의 중요성이 대두되고 있다. 그러나 아직까지 해상조건의 세굴현상을 파악하기 위한 적절한 세굴평가 기준이 제시되어 있지 않고 대부분 자연 하천교량 기준에 의해 해상교량의 세굴평가가 이루어지고 있는 실정이다. 교량에서 발생하는 세굴 현상은 교량 기초의 안정성에 치명적인 영향을 줄 수 있고 나아가서는 교량의 붕괴 원인이 될 수 있다. 또한 교량기초 지반의 지지력 부족이나 적정피복두께 결여 등의 원인으로 구조적인 문제점을 초래할 수 있다. 해상교량의 경우에는 조석에 의한 왕복류, 파 흐름의 상호작용, 점착성 지반 등 세굴에 영향을 미칠 수 있는 요인들이 복합적으로 작용하므로 교량 건설 전부터 해상조건을 반영한 다각적인 세굴검토가 요구된다. 본 연구는 강한 조석류가 작용하고 넓은 조간대를 형성하고 있는 인천대교의 세굴심을 합리적으로 산정하기 위하여 다학제적인 연구를 시도한 것이다. 본 연구에서는 해상조건의 침식유발특성을 파악하기 위한 연구로서 수치모형 및 수리모형 실험을 수행하고, 지반종류에 따른 침식저항능력을 파악하기 위한 세굴률 실험을 수행하였다. 더불어 인천대교 건설현장에 타설되어 있는 대구경 시험말뚝에 대한 실시간 세굴모니터링을 실시하여 얻은 현장관측 자료를 검증자료로 사용함으로써 종합적인 세굴검토를 통하여 다학제적이고 합리적인 해상교량의 세굴심을 평가하고자 한다.

• The Korean Journal of Zoology
• /
• v.33 no.4
• /
• pp.454-460
• /
• 1990

The effed of acrylamide on the nervous system has heen morphologically studied using light and electron microscopes. The light micrographs on central and pedpheral nervous tissues of mouse treated with acrylamide monomer showed total vacuolation of spinal cord, cell degradation containing neuron and neuroglia, and distal nerve fiber degeneration. The electron micrographs showed ultrastrudural changes. Abnormal mitochondria in neuron, splitting of myelin sheath in lumbar ventral root nerve, partial disintergration of myelin sheath and axoplasmic degeneration in sciatic nerve, and overafl polyneuropathies in nervous system were observed. These results suggest that acrylarnide intoxicated mouse shows distal behavioral neuropathy as an earlist clinical sign, but the initial effect of acrylamide on the nervous system seems to appear at nearly the same time in both central and peripheral nervous systems.

• Proceedings of the Korean Society of Agricultural Engineers Conference
• /
• 2000.10a
• /
• pp.1-24
• /
• 2000

21세기는 생명, 환경, 정보를 주제로 새 시대를 맞이하고 있다. 20세기 절대빈곤에서 벗어나기 위한 성장제일주의의 경제개발정책은 짧은 시간에 성공적으로 달성되어 높은 문화수준과 산업사회를 이룰 수 있었다. 한편, 국민생활향상과 산업발전에 결정적 역할을 해왔던 수자원개발은 동강에서, 시화호에서, 지리산, 인천 앞바다에서 개발 부작용으로 생태와 환경이 심한 몸살을 앓기 시작하고 있다. WTO에 의한 시장개방으로 생산구조가 붕괴되고 농촌지역이 공동화될 것을 걱정하고 있다. 누군가는 농촌에서 농사를 짓고 살아야만 국가의 산업구조가 유지되고 아름다운 국토의 자연환경을 보전할 수 있다. 농촌은 식량생산을 위한 공간과 인간생활을 위한 공간 등 두 가지 기능을 가진 공간이다. 쾌적한 농촌을 이룩하려면 농업생산성을 향상시켜 농업소득을 높이고, 농공단지의 활성화와 농촌관광과 휴양시설에 의한 농외소득을 강화해야 한다. 또한, 농업은 식량의 안정적 공급은 물론 홍수 및 토양침식 억제, 수자원함양, 수질정화, 대기정화, 생물 다양성 등 환경보전적 기능이 WTO에 대응하여 쌀시장을 지킬 수 있는 논리로 새롭게 평가받고 있다. George Brokeway (경제인의 종말, 1991)의 “ 이윤극대화라는 경제원칙이 인간의 자연파괴와 기상이변 앞에 모순을 드러내고 있어 경제학의 인간화를 요구하고 있다.”는 지적에 비교우위론자들은 다시 한번 귀기울여주기 바란다.

• Explosives and Blasting
• /
• v.22 no.3
• /
• pp.43-55
• /
• 2004

Use term of tower style construction exceeds recently. Accordingly, according to construction safety diagnosis result, achieve removal or Improvement construction. But when work removal, must shorten shut down time. Therefore, removal method of construction to use blasting demolition of construction is very profitable. Influence construction and equipment by blasting vibration and occurrence vibration caused by felling impact. Is using disadvantageous machine removal method of construction by and economic performance by effect of such vibartion. Therefore, this research studied techniques to forecast vibartion level happened at blasting demolition and vibration reduction techniques by use a scaled model test.

• Journal of the Korean Electrochemical Society
• /
• v.3 no.2
• /
• pp.85-89
• /
• 2000

For replacing Li metal at Lithium ion Battery(LIB) system, we used carbon powder material which prepared by Pyrolysis of Phenol resin as starting material. It became amorphous carbon by Pyrolysis through it's self condensation by thermal treatment. Amorphous carbon can be doped with Li intercalation and deintercalation because it has wide interlayer. However, it has a problem with structural destroy due to weak carbon-carbon bond. So, we used $ZnCl_2$ as the pore-forming agent. This inorganic salt was used together with the resin serves not only as the pore-forming agent to form open pores, which grow into a three-dimensional network structure in the cured material, but also as the microstructure-controlling agent to form a loose structure doped with bulky dopants. We used SEM in order to find to difference of structure, and can calculate the distance of interlayer by XRD analysis. CV test showed oxidation and reduction.

• Proceedings of the Korea Concrete Institute Conference
• /
• 2008.11a
• /
• pp.935-940
• /
• 2008

When reinforced concrete is subjected to high temperature as in fire, there is deterioration in its properties of particular importance are loss in compressive strength, cracking and spalling of concrete, destruction of the bond between the cement paste and the aggregates and the gradual deterioration of the hardend cement paste. Assessment of fire-damaged concrete usually starts with visual observation of color change, cracking and spalling of the surface. In this paper, it was reported the trends of research and practical use on the Explosive Spalling Properties and Performance Based of Structural Design of the High-Strength Concrete.