• Proceedings of the Korean Institute of Industrial Safety Conference
• /
• 2003.10a
• /
• pp.184-187
• /
• 2003

다양한 부식 형태 준 금속부식은 대기중, 수중, 지중, 화학약품 등의 부식환경에 의해 영향을 받는다. 특히 금속 표면의 산화 반응에 의해 생성되는 녹(Rust)은 iron, steel, bronze, aluminium 등의 대상소재를 사용하는 일반 가전제품, 산업공정설비 및 각종 구조물 등에 작용하여 원재료 손상, 내구수명 저하, 구조물 붕괴, 화재 및 폭발위험성 등 대부분 안전사고로 직결되는 것이 일반적이다.(중략)

• 해운
• /
• no.9 s.66
• /
• pp.20-25
• /
• 2009

최근 철강 원료업계의 대규모 구조개편 움직임이 재부상하고 있으며, 과거와는 다른 특징을 가지며 전개되고 있다. BHP빌리톤과 Rio Tinto의 철광석 JV 설립 합의를 비롯하여, 철광석 및 원료탄 업계에서 메이저업체 간 합종연횡이 신조류로 등장했다. 이에 따라 현재의 장기가격 체제가 붕괴되고 최대 소비국인 중국과 메이저 원료사의 주도로 가격 체제가 다양한 형태로 변화될 전망이다. 다음은 포스코경영연구소가 발표한 보고서를 정리한 것이다.

• Review of KIISC
• /
• v.12 no.5
• /
• pp.1-7
• /
• 2002

양자 정보에 대한 도청은 양자 상태에 대한 측정이며, 양자역학에서의 측정은 양자 상태의 붕괴를 수반하게 되므로 원래의 정보 형태를 변형시키게 된다. 이를 이용하여 도청 시도의 여부를 거의 완벽하게 판단할 수 있으며, 따라서 고도의 보안이 유지되는 키분배 방식이 가능하게 된다. 이를 양자 암호 혹은 양자 키분배 프로토콜이라고 한다. 양자 역학의 기본 구조와 일반 원리를 제시하고, 이를 바탕으로 한 양자 암호의 기본 개념과 원리를 설명하고자 한다. 이에 대한 예로 대표적인 키분배 방식을 소개한다.

• The Journal of Engineering Geology
• /
• v.26 no.1
• /
• pp.15-22
• /
• 2016

Hydraulic falling head and slug tests were carried out in an alluvium aquifer using a borehole stability device. The hydraulic testing had proved difficult in alluvial formations of sands and gravels due to borehole collapse and unstable borehole walls within the test section. This study aims to improve the hydraulic test results by using a borehole stability device. The device can minimize the collapse of borehole walls, and the use of a filter with a constant opening ratio improves the calculations per unit area of the test section. Permeability obtained from the falling head test without a borehole stability device was 8.82 × 10⁻⁵m/sec. When the borehole stability device was installed in the same test section the measured permeability increased to 4.00 × 10⁻⁴m/sec, which is 4.5 times that obtained without the borehole device. The relatively low permeability obtained using the conventional test method is attributed to the presence of a fine-grained slime generated during drilling and a reduction of the test area in the test interval due to a gradual collapse of the borehole walls. This study considers how the use of a borehole stability device to prevent borehole collapse can influence the results of hydraulic tests in alluvial formations. It is expected that the results can be used as a basis for improving the reliability and applicability of hydraulic tests performed in alluvial aquifers.

• Journal of Korean Society of Forest Science
• /
• v.108 no.2
• /
• pp.208-215
• /
• 2019

The goal of this study was to analyze the reactivity of a volumetric water content sensor (soil moisture sensor) and tensiometer and to review their use in the early detection of a shallow landslide. We attempted to demonstrate shallow and rapid slope collapses using three different soil ratios under artificial rainfall at 120 mm/h. Our results showed that the measured value of the volumetric water-content sensor converged to 30~37%, and that of the tensiometer reached -3~-5 kPa immediately before the collapse of the soil under all three conditions. Based on these results, we discussed a temporal range for early warnings of landslides using measurements of the volumetric water content sensors installed at the bottom of the soil slope, but could not generalize and clarify the exact timing for these early warnings. Further experiments under various conditions are needed to determine how to use both sensors for the early detection of shallow landslides.

• Microbiology and Biotechnology Letters
• /
• v.36 no.3
• /
• pp.209-214
• /
• 2008

VBNC (Viable but nonculturable) state is an adaptive response of cells in adverse environments, which lead cell not grow on routine nutrient agar. In this study, we induced VBNC in Escherichia coli using copper and verify the characterization of it. After treatment of copper, we didn't detect any cells via plate cultivation, namely, colony forming unit (CFU) was zero. However, we identified the existence of VBNC by staining live cells with Live/Dead BacLight bacterial viability kit and counting them through flow cytometry. Then we isolated genomic DNA and RNA from VBNC-induced cells and analyzed the stability of them. Degradation of RNA is more severe than that of DNA and RNA is degraded as specific fragments. In addition, we showed the morphology of VBNC cell by Bio-Transmission Electron Microscope (Bio-TEM). VBNC cell showed impaired periplasmic space and inner and outer membrane were separated and the amount of cytosol were significantly decreased.

• Journal of the Korea Concrete Institute
• /
• v.26 no.3
• /
• pp.393-400
• /
• 2014

Structures are often subject to vehicle collision which can be accidental or terrorist attack. Previous research shows that the damage in major columns may result in progressive collapse of a whole building. This study investigates the performance of a steel column standing on a reinforced concrete footing subjected to a vehicle collision. The size and the axial load of the steel column are determined based on the assumption that it is the first story corner column in a typical three-story building with six meter span length. The finite element model of a eight-ton single unit truck provided by the NCAC (National Crash Analysis Center) is used in the numerical analysis. The finite element analysis is performed using the LS-DYNA, and the results show that the behavior of the column subjected to car impact depends largely on the column-foundation connection detail.

• KSCE Journal of Civil and Environmental Engineering Research
• /
• v.13 no.4
• /
• pp.217-226
• /
• 1993

This study is related to the surface subsidence due to the collapse of a underground void during earthquakes. The amount of the settlement due to the collapse of a underground void will depend on the depth of the void, the initial condition of unit weight of sand, the size and type of foundation, the strength of earthquake, the size of a void, etc. The purpose of the paper is to estimate the amount of the subsidence, analyse the factors affecting the subsidence, and develop a program determining the probability of the damages to structures in terms of absolute and differential settlement and rotational settlement. On the base of the results obtained in this study, when the depth of a void is constant and the width of the void increases, the change of the subsidence factor due to the angle of internal friction and the actual effective factor of the void become smaller than that due to the unit weight of sand deposits. In the same condition, the probabilities of damages due to the absolute and differential settlement increase, and those due to the rotational settlement decrease.

• Journal of Korean Association for Spatial Structures
• /
• v.10 no.2
• /
• pp.61-68
• /
• 2010

The collapsing accidents of pipe greenhouses in the farmhouse have been increased duo to heavy snow load. However, the study on exact structure analysis to prevent the collapse of pipe greenhouses is rare and the damage of the farmhouse is annually repeated. The method of existing structure analysis is basically made of linear elastic analysis based on the micro displacement. But the actual stiffness of the pipe greenhouse is significantly weaker than the stiffness of buildings and the load acting on the greenhouses gets to become relatively bigger. It means that the geometry shape of greenhouses changes so that the relation of strain-displacement gets to indicate a nonlinear behavior. Therefore, this study is performed to evaluate the structural safety so as to prevent the collapse of pipe greenhouses, which are the single-span greenhouse(farmhouse guidance shape, G) and multi-span greenhouse(farmhouse supply shape, 1-2W), by performing the large-displacement analysis considering nonlinear effects.

• Journal of the Korean Society of Marine Environment & Safety
• /
• v.17 no.3
• /
• pp.295-300
• /
• 2011

Ship are a box-shaped structure. It is used often fore and aft parts, bilge strake, deck with camber of ship structures. When this structure is compared with flat plate structure, it different to behaviour. Generally, if it subjected to axial compressive load, ultimate strength depend on the change of curvature. Also, In this paper, stiffened curved plate with 1/2+1+1/2 bay model subjected to compressive load carried out the elasto-plastic large deflection series analysis. and parameter effect considered slender ratio, web height/thickness as well as change of curvature and investigated collapse mode for analysis model.