• Journal of Korean Society of Rural Planning
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• v.11 no.3 s.28
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• pp.53-57
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• 2005

Up to recently building are constructed focusing on the convenience of residential condition. However, environmental-friendly materials is required for construction as people are spending more time inside buildings and causes of many problems like sick-building syndrome are known due to the noxious gases and polluted air originated from construction materials. Although loess(hwangtoh) is an environmental-friendly material, it has limitations in compressive strength far a construction material. The purpose of this study is to suggest the optimal ratio of loess(hwangtoh) mortar by tests of compressive strength comparing with standard strength of floor finishing mortar and evaluate the usability of loess(hwangtoh) mortar for floor finishing material through an impact test, a cracking test and a abrasion test. Based on the results of this study, 86% of loess(hwangtoh) and 14% of inorganic binder is suggested for the optimal mixture ratio of loess(hwangtoh) mortar. Moreover, the characteristics of loess(hwangtoh) is suitable for floor finishing material in impact, crack, abrasion.

• Korean Journal of Materials Research
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• v.12 no.7
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• pp.533-539
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• 2002

Porous anodic aluminum oxide layer for nano templates was prepared in acidic solutions. In order to investigate effects of 2nd anodization on ordered formation behaviors of the porous oxide layers, electrochemical and microstructural studies were performed, primarily using TEM, FE- SEM, AFM, and Ultramicrotomy. The pore diameter of the anodic oxide layer increased approximately linearly with increasing voltages, and to the contrary, the pore density decreased. It was shown that 2nd anodizing on the cell base after dissolving 1st anodic oxide layer was remarkably effective for forming ordered array of the pores, comparing with the case for 1st anodization only. And for controlling the diameter of pores, widening method by chemical dissolution seemed more practical than by electrochemical methods.

• Korean Journal of Materials Research
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• v.6 no.4
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• pp.388-394
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• 1996

Tetrakis-Diethylamido-Titanium(TDAET) 기체를 이용한 TiN 박막의 막질, 성장률, 및 도포성에 운반기체(N2, He)가 미치는 효과에 관한 조사를 하였다. TiN 박막의 막질과 성장속도는 운반기체에 의해 상당히 많은 영향을 받고 있으며, He 운반기체를 사용하였을 때 성장속도는 낮으나 낮은 비저항(-2500$\mu$$\Omega$-cm)과 낮은 산소 함량을 갖는 박막을 얻을 수 있었다. He 운반기체를 이용하여 증착된 TiN 박막은 대기 중에 노출시켰을 때 비저항이 더 이상 증가하지 않는 안정된 박막 특성을 보이고 있었다. 이와는 대조적으로, N2 운반기체에 따라 다르게 나타나는 막질의 안정성은 막 중에 함유된 산소량에 기인하는 것으로 판단된다. 또한 TDEAT 단일 증칙원 공정에서의 도포성은 aspect ratio가 2.0인 접촉창에서 18-65%인 값을 얻을수 있었고, He 운반기체의 경우항상된 도포성이 얻어졌다.

• Korean Journal of Materials Research
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• v.12 no.7
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• pp.540-544
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• 2002

Hydration treatments were performed on the pure aluminum substrate at $100^{\circ}C$ followed by anodizing and heat treatments on the layers. The transformation behaviors of the oxide layers according to the hydration treatment were studied using TEM, XRD, RBS etc. Above $90^{\circ}C$ the hydrous oxide film could be formed, which were turned out to be hydrous oxides(AlOOH $nH_2$O). The anodization on the hydrous oxide film was more effective for the transition of amorphous anodic oxides to the crystalline $\Upsilon-Al_2$ $O_3$ comparing with the case for anodizing on the aluminum substrate without hydration treatment And additional heat treatments were also helpful for the acceleration of the transformation of the hydrous oxide to $\Upsilon-Al_2$ $O_3$. During the heat treatment the interface between $\Upsilon-Al_2$ $O_3$and the hydrous oxide layers migrated to the outer side of hydrous layer.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.13 no.8
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• pp.3345-3351
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• 2012

In this study, simulation of an underwater platform system which is able to perform the underwater test is implemented to predict its dynamic characteristics. Accordingly, its governing equations are derived to construct the mathematical model. From the proposed model, the time in flooding and the pressure of ballast tank in blowing air to come up are predicted. In addition, simulation of the stability of the system for repulsive force of the tube by compressed air is carried out. Their results will be used to select valves, air tanks as well as design the system including ballast tanks. And they will help users operate it efficiently.

• Journal of KIISE:Databases
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• v.33 no.1
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• pp.117-128
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• 2006

In this paper, we propose a streaming method for XML data that supports energy-efficient processing of queries over the stream in mobile clients. We propose new stream organizations for XML data which have different kinds of addresses to related data in a stream. We describe event-driven stream generation algorithms for the proposed stream structures and provide search algorithms for simple XML path queries which leverage the access mechanisms incorporated in the stream. Experimental results show that our approaches can effectively improve the tuning time performance of user queries in a wireless broadcasting environment.

• Resources Recycling
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• v.13 no.5
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• pp.51-56
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• 2004

Economic benefits of the dry bottom ash handling system over the wet bottom ash handling system in a new 500MW${\times}$2units pulverized coal thermal power plant in Korea were evaluated. The higher initial capital cost in the dry bottom ash handling system was estimated. However, this higher initial capital costs would be compensated with reductions of the operating cost mainly due to the recycling of bottom ash. Economic analysis showed that the payback period of 4.9 years and the internal rate of return at 21.1% were expected for the additional initial capital cost of the dry bottom ash handling system.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.12 no.10
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• pp.1815-1821
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• 2008

Recently, Since growth of the ubiquitous computing environment and development of networking technology, User is a possible to connect the Internet out of constraints of time and space. Using RFID of core technique of ubiquitous computing, various application cases are increasing rapidly. In this paper, we propose design of the User-Centered Document Generation System which can makes several format of documents using RFID information stored in relational database. Our system can makes HTML file, EXCEL file and XML document file that provide for users over internet. Also, whenever user need to the document that can save easy and conveniently them on local computer and then is a possible to exploit them for other works.

• Transactions of the Korean Society of Pressure Vessels and Piping
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• v.15 no.1
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• pp.33-39
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• 2019

An 1,500MW advanced power reactor required the standard design approval by a Korean regulatory body in 2014. The reactor has been designed to have a 4-train independent safety concept and a passive auxiliary feedwater system (PAFS). The full power risk or core damage frequency (CDF) of 1,500MW advanced power reactor has been reduced more than that of APR1400. However, the risk during the low power and shutdown (LPSD) operation should be reduced because CDF of LPSD is about 4.7 times higher than that of internal full power. The purpose of paper is to analysis design alternatives to reduce risk during the LPSD. This paper suggests design alternatives to reduce risk and presents sensitivity analysis results.

• Transactions of the Korean Society of Pressure Vessels and Piping
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• v.17 no.2
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• pp.90-100
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• 2021

Molten corium-concrete interaction (MCCI) is one of the most important phenomena that can lead to the potential hazard of late containment failure due to basemat penetration during a severe accident. In this study, MCCI analytical models of the CORQUENCH code were prepared through verification calculations of several experiments, which had been performed using concrete types similar to those of the calandria vault floor in CANDU-6 plants. The behaviors of thermal-hydraulic variables related to MCCI phenomena were analyzed under the conditions of dry floor and water flooding during the severe accident stemming from a hypothetic station blackout. Uncertainty analyses on the ablation depth were also carried out. It was estimated that the concrete ablation was not interrupted due to the continuous MCCI process under the dry condition but was terminated within 24 hours under the water flooding condition. It was confirmed that the water flooding as a mitigating action was effective to achieve the quenching and thermal stabilization of the melt discharged from the calandria vessel, showing that the present models are capable of reasonably simulating MCCI phenomena in CANDU-6 plants. This study is expected to provide the technical bases to the accident management strategy during the late-phase severe accidents.