• Geophysics and Geophysical Exploration
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• v.2 no.1
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• pp.8-16
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• 1999

In terms of high resolution, seismic reflection survey is by far the most significant geophysical method applied to define subsurface structure. In shallow seismic reflection survey, it is, however, difficult to obtain high resolution image due to both the wave attenuation in the unconsolidated layer and the existence of source-generated surface waves Therefore, when collecting data, it is imperative to select proper equipments and choose optimum field data acquisition parameters for acquiring high S/N data. In this survey, a small size hammer was used as a low energy source and 40-Hz vertical geophones were used as receivers. Trigger signal was obtained from the hammer starter attached in the aluminum plate and thus it was possible to control the source onset time for the vertical stack. During the field work, a modified standard CMP technique was introduced to achieve the many-fold CMP data effectively. Data processing was conducted by the 'Seismic Unix' which is mounted on PC with a Linux operating system. The main distinctions were the emphasis and detail placed on near-surface velocity analysis and the extra care exercised in muting.

• Coupled systems mechanics
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• v.2 no.1
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• pp.53-83
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• 2013

Sea waves induce significant pressures on coastal surfaces, especially on rocky vertical cliffs or breakwater structures (Peregrine 2003). In the present work, this hydrodynamic pressure is considered as the excitation acting on a piezoelectric material sheet, installed on a vertical cliff, and connected to an external electric circuit (on land). The whole hydro/piezo/electric system is modeled in the context of linear wave theory. The piezoelectric elements are assumed to be small plates, possibly of stack configuration, under a specific wiring. They are connected with an external circuit, modeled by a complex impedance, as usually happens in preliminary studies (Liang and Liao 2011). The piezoelectric elements are subjected to thickness-mode vibrations under the influence of incident harmonic water waves. Full, kinematic and dynamic, coupling is implemented along the water-solid interface, using propagation and evanescent modes (Athanassoulis and Belibassakis 1999). For most energetically interesting conditions the long-wave theory is valid, making the effect of evanescent modes negligible, and permitting us to calculate a closed-form solution for the efficiency of the energy harvesting system. It is found that the efficiency is dependent on two dimensionless hydro/piezo/electric parameters, and may become significant (as high as 30 - 50%) for appropriate combinations of parameter values, which, however, corresponds to exotically flexible piezoelectric materials. The existence or the possibility of constructing such kind of materials formulates a question to material scientists.

• Journal of the Korea Safety Management & Science
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• v.14 no.2
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• pp.83-89
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• 2012

In this study, FDS fire simulation experiments and measured wind speed by applying the exterior installation portion for blocking the spread of the fire was investigated. As a result, aluminum composite panels installed in the lower and the upper part of the panel to remove all the lower side, and then the maximum wind speed 0.24 m/s and the upper side 0.58 m/s were measured. In the FDS, the measured wind speed difference air currents are approximately 3.7 times in 12 seconds, the occurrence of 17 seconds early moment wind 2.2 m/s was measured from. Before and after the fire occurred in early of the air velocity about 39 seconds was 3.5 times difference. Such air currents caused by the temperature of the building but also by the building height was found. Turbulent flame of fire by expanding the vertical extent of damage become greatly important factor. Therefore, through the exterior installation portion of the block that can delay the spread of fire is expected that this should be taken.

• ETRI Journal
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• v.33 no.6
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• pp.904-913
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• 2011

Three-dimensional (3D) memories using through-silicon vias (TSVs) as vertical buses across memory layers will likely be the first commercial application of 3D integrated circuit technology. The memory dies to stack together in a 3D memory are selected by a die-selection method. The conventional die-selection methods do not result in a high-enough yields of 3D memories because 3D memories are typically composed of known-good-dies (KGDs), which are repaired using self-contained redundancies. In 3D memory, redundancy sharing between neighboring vertical memory dies using TSVs is an effective strategy for yield enhancement. With the redundancy sharing strategy, a known-bad-die (KBD) possibly becomes a KGD after bonding. In this paper, we propose a novel die-selection method using KBDs as well as KGDs for yield enhancement in 3D memory. The proposed die-selection method uses three search-space conditions, which can reduce the search space for selecting memory dies to manufacture 3D memories. Simulation results show that the proposed die-selection method can significantly improve the yield of 3D memories in various fault distributions.

• KIEAE Journal
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• v.7 no.6
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• pp.3-8
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• 2007

Recently, because of the continuous rise of international oil price, energy saving is strongly demanding. So, Ecological technics of architecture such as use of natural energy have been actively explored in the field of building. In the method of utilizing natural energy, the key point is to saving energy effectively as not lowering the comfort of indoor environment, various systems investigated. Many papers about double skin facade system have been reported, it is announced broadly that the system is very effective in improvement of natural ventilation and indoor thermal environment, and also protecting outdoor sound. The shaft box facade is a special form of box window construction. It consists of a system of box windows with continuous vertical shafts that extend over a number of stories to create a stack effect. The facade layout consists of an alternation of box windows and vertical shaft segments. This research investigated the natural ventilation performance of shaft box type balcony which conform the shaft box type double skin to the exiting balcony construction. First, analyzed various types of exiting apartments, proto-type was decided. By using virtual environment Program, modeling the proto-type, compared the contribution of air temperature and the effect of outdoor air cooling. by this research, we confirmed that shaft box type balcony had many possibility for improvement of indoor environment.

• 한국신재생에너지학회:학술대회논문집
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• 2010.06a
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• pp.186.3-186.3
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• 2010

본 논문은 우리나라와 같이 평균풍속이 낮고 바람 방향이 수시로 변하는 지역에 적합한 풍력발전 시스템에 관하여 논한다. 특히, 풍향에 상관없이 효율을 보장하고, 아주 약한 풍속 조건에서도 기동(Cut-in)되며, 낮은 평균풍속 5~6m/s인 지역에서도 경제적으로 풍력발전 단지의 구축이 가능하며, 다양한 지역에 설치가 가능하고, 소음이 적고 친(親) 환경적이며, 양산이 가능해 납기를 예측할 수 있으며 그리고 모든 부품 및 시스템의 국산화가 가능해야 한다는 7가지 조건을 만족하는 풍력발전시스템으로 이를 실현시키기 위하여 현재 풍력발전시스템의 가장 앞선 요소기술(state-of-the-art technology)인 직접구동 방식, 적층식, STR 블레이드, AFPM동기발전기, 자기부상 및 전자브레이크 등 5가지 기술을 복합 융합하여 최고의 효율 및 성능을 보장해 주는 적층 연곡형 시스템이다.

• 한국신재생에너지학회:학술대회논문집
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• 2008.05a
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• pp.550-553
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• 2008

In this paper, experiments of air-breathing proton exchange membrane fuel cell (PEMFC) for mobile devices were carried out according to the cathode conditions. These conditions are defined by the cathode flow field plate type (the channel type, the open type) and the cathode surface direction. Single cell and 6-cell stack were used in this experiments. The experimental results showed that the open type cathode flow field plate gave better performance for small size PEMFCs because the open type cathode plate allowed better air convection than the channel type cathode plate. In the experiments related to the direction of the slits on the cathode flow field plate, the horizontal slit cell was better than the vertical slit cell. With respect to the cathode surface direction, when the cathode surface is placed in the direction normal to the ground, PEMFC generated more stable power in the mass transport loss region.

• 한국신재생에너지학회:학술대회논문집
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• 2009.06a
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• pp.813-816
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• 2009

A commercial-scale RDF boiler that its burning capacity is 400 kg-RDF/hr and steam production capacity is 2 ton/hr. It has a chain type stoker and waste heat recovery system. Heat exchanger is vertical water-pipe so that soot blowing and removal is convenient during operation. Dry scrubber, bag filter and activated carbon tower have been installed for the reduction of air pollutant gases and dust. Analysing data of pollutants from stack such as $SO_x$. $NO_x$ and dioxin shows so good results that the boiler system could comply the regulated emission limits.

• Proceedings of the Materials Research Society of Korea Conference
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• 2011.05a
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• pp.11.1-11.1
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• 2011

We have developed a simple synthetic method for fabricating a wafer-scale colloidal crystal film of 2D crystals in a 1D stack based on a combination of two simple processes : the self-assembly of polystyrene (PS) nanospheres at the water-air interface and the layer-by-layer (LbL) scooping transfer technique. The main advantage of this approach is that it allows excellent control of the thickness (at a layer level) of the crystals and the formation of a vertical crack-free layer over a wafer-scale (4 inch). We investigate the optical and morphological properties of the PhC multilayers fabricated using various mono-sized colloidal crystals (250, 300, 350, 420, 580, 720, and 850 nm), and mixed binary colloidal crystals (300/350 and 250/350 nm).

• KIEAE Journal
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• v.13 no.1
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• pp.75-81
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• 2013

The balcony of our apartment building consists of unique construction similar to double skin. It is announced broadly that double skin is very effective system in improvement of natural ventilation and indoor thermal environment, and outdoor sound protection. So, for the improvement of indoor climate and energy saving, many peoples studied about environmental performance of our balcony construction. This study focus on shaft box facade, special form of box window construction. It consists of a system of box window with continuous vertical shafts that extend over a number of stories to create a stack effect. Proto-type was decided by analyzing various types of exiting apartments. Shaft box type balcony was created by setting up shaft space at a part of balcony. Air flow and contribution of air temperature were simulated, performance of shaft box type balcony was compared with existing balcony. Finally, we confirmed that shaft box type balcony has many possibility for improvement of indoor environment.