• Journal of Nuclear Fuel Cycle and Waste Technology(JNFCWT)
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• v.3 no.4
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• pp.301-307
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• 2005

The morphology of the high burnup $UO_2$ spent fuel, which was oxidized and annealed in a PIA (Post Irradiation Annealing) apparatus, has been observed. The high burnup fuel irradiated in Ulchin Unit 2, average rod burnup 57,000 MWd/tU, was transported to the KAERI's PIEF. The test specimen was used with about 200 mg of the spent $UO_2$ fuel fragment of the local burnup 65,000 MWd/tU. This specimen was annealed at $1400^{\circ}C$ for 4hrs after the oxidation for 3hrs to grain boundary using the PIA apparatus in a hot-cell. In order to oxidize the grain boundary, the oxidation temperature increased up to $500^{\circ}C$ and held for 3hrs in the mixed gas (60 ml He and 100 ml STD-air) atmosphere. The amount of 85Kr during the whole test process was measured to know the fission gas release behavior using the online system of a beta counter and a gamma counter. The detailed micro-structure was observed by a SEM to confirm the change of the fuel morphology after this test. As the annealing temperature increased, the fission products were observed to move to the grain surface and grain boundary of the $UO_2$ matrix. This specimen was re-structured through the reduction process, and the grain sizes were distributed from 5 to $10\;{\mu}m$.

• Cross-Cultural Studies
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• v.51
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• pp.161-191
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• 2018

In the beginning of the 20th century, post-colonialism has directly raised questions about western-centered universalism. One of its main achievements is that the political liberation of a colonial society does not guarantee the social, economic and cultural liberation of a society. Therefore, the discourse of liberation in the Western society, in particular, Marxism, nationalism, feminism and postmodernism, cannot be directly applied to the non-Western society. As a result, Western and non-Western societies are unfortunately dreaming of different futures and liberation; therefore, a'geopolitical dialogue' is needed between them. However, the theorists' efforts for postcolonial liberation failed to distinguish themselves from the western-centric traditions. It is also true that they have, in conjunction with these traditions, established their own power. As we know, many of the postcolonial criticisms somehow had relations with the West. This study will re-read the postcolonial thought of $Aim{\acute{e}}$ $C{\acute{e}}saire$, the father of the so-called $N{\acute{e}}gritude$, as a 'non-western resistance discourse'. Through this process, we have a chance to reflect on $C{\acute{e}}saire$ and his postcolonial thoughts.

• Journal of the Korean Society of Hazard Mitigation
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• v.4 no.1 s.12
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• pp.51-56
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• 2004

In this study, the variation of water quality in Osan stream was investigated through continuous monitoring, and mass balance and metabolism occurred into water body were estimated to set up effective management plan for water quality of small urban stream. From the results of continuos investigation of water quality in Osan stream, the things written as follows must be previously done to improve water quality of main stream. Firstly, it need that effective management plan for tributaries must be set up to improve the water quality in main stream. Secondly, the counter plan for re-eruption of pollutants from sediment in main-stream is required to prevent inner pollution. In this study, we showed that small urban stream can be managed effectively by simple investigation to prevent deterioration of water quality. Therefore continuous monitoring for water quality in stream is important to improve water quality, furthermore matter cycle and mass balance happening in the stream environment must be correctly estimated to make up healthy stream environment.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.29 no.5 s.236
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• pp.577-589
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• 2005

The present study has numerically investigated two-dimensional laminar flow over a steadily rotating circular cylinder with a uniform planar shear, where the free-stream velocity varies linearly across the cylinder. It aims to find the combined effect of rotation and shear on the flow. Numerical simulations using the immersed boundary method are performed for the ranges of $-2.5{\le}\alpha{\le}2.5$ and $0{\le}K{\le}0.2$ at a fixed Reynolds number of Re=100, where a and K are respectively the dimensionless rotational speed and velocity gradient. Results show that the positive shear, with the upper side having the higher free-stream velocity than the lower one, favors the effect of the counter-clockwise rotation $(\alpha<0)$ but countervails that of the clockwise rotation $(\alpha>0)$. Accordingly, the absolute critical rotational speed, below which vortex shedding occurs, decreases with increasing K for $(\alpha>0)$, but increases for $\alpha>0$. The vortex shedding frequency increases with increasing \alpha (including the negative) and the variation becomes steeper with increasing K. The mean lift slightly decreases with increasing K regardless of the rotational direction. However, the mean drag and the amplitudes of the lift- and drag-fluctuations strongly depend on the direction. They all decrease with increasing K for $\alpha>0$, but increase for $\alpha<0$. Flow statistics as well as instantaneous flow folds are presented to identify the characteristics of the flow and then to understand the underlying mechanism.

• Journal of the Korean Society of Environmental Restoration Technology
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• v.12 no.2
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• pp.61-72
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• 2009

This study aims to analyze the current situation of and issues in the structure of urban neighborhood parks and park facility installation in cities in Gyeonggi-do. Then, based on its findings, plans to improve the space structure of the parks were examined and suggested to raise the city environment improvement function and green area base function of urban parks and fully satisfy users' needs for pleasant rest, recreation and cultural activities. The findings showed that, within parks, the area of grass where access was restricted reached about 24.4% in average. In other words, only 75.6% of total park area could be freely used by park visitors. As for an improvement plan, the grass area where access is limited may be converted into a gras area that can be freely used to raise the park use area, which currently stands only at 75.6%, to 100%. The result of cross analysis through Chi-Square Test regarding lawn use as well as regarding (dis)agreement with reduction of lawn, based on the investigation of cognition, showed a significant agreement of park users with reduction of green areas. Therefore it is considered that lawn space must be reduced according the result of the analysis, to set up plans for facility space that would meet the desires of users. The analysis of user behaviors revealed that many of them used square spaces and walks; therefore it is considered that re-structuring of space is necessary according to local characteristics. This study also made some policy suggestion. urban parks must be a base of city green areas to counter climate changes. When developing a park creation plan, a user demand survey must be conducted in advance. In addition. grass construction methods should be improved to tolerate foot pressure.

• Tribology and Lubricants
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• v.31 no.3
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• pp.79-85
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• 2015

RC delay is a critical issue for achieving high performance of ULSI devices. In order to minimize the RC delay time, we uses the CMP process to introduce high-conductivity Cu and low-k materials on the damascene. The low-k materials are generally soft and fragile, resulting in structure collapse during the conventional high-pressure CMP process. One troubleshooting method is electrochemical mechanical polishing (ECMP) which has the advantages of high removal rate, and low polishing pressure, resulting in a well-polished surface because of high removal rate, low polishing pressure, and well-polished surface, due to the electrochemical acceleration of the copper dissolution. This study analyzes an electrochemical state (active, passive, transpassive state) on a potentiodynamic curve using a three-electrode cell consisting of a working electrode (WE), counter electrode (CE), and reference electrode (RE) in a potentiostat to verify an electrochemical removal mechanism. This study also tries to find optimum conditions for ECMP through experimentation. Furthermore, during the low-pressure ECMP process, we investigate the effect of current density on surface roughness and removal rate through anodic oxidation, dissolution, and reaction with a chelating agent. In addition, according to the Faraday’s law, as the current density increases, the amount of oxidized and dissolved copper increases. Finally, we confirm that the surface roughness improves with polishing time, and the current decreases in this process.

• Proceedings of the KIEE Conference
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• 2006.07b
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• pp.1159-1160
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• 2006

As the grid-connected photovoltaic power conditioning systems (PVPCS) are installed in many residential areas, this has raised potential problems of network protection on electrical power system. One of the numerous problems is an Island phenomenon. There has been an argument that because the probability of islanding is extremely low it may be a non-issue in practice. However, there are three counter-arguments: First, the low probability of islanding is based on the assumption of 100% power matching between the PVPCS and the islanded local loads. In fact, an island can be easily formed even without 100% power matching (the power mismatch could be up to 30% if only traditional protections are used, e.g. under/over voltage/frequency). The 30% power-mismatch condition will drastically increase the islanding probability. Second, even with a larger power mismatch, the time for voltage or frequency to deviate sufficient to cause a trip, plus the time required to execute the trip (particularly if conventional switchgear is required to operate), can easily be greater than the typical re-close time on the distribution circuit. And, third, the low-probability argument is based on the study of PVPCS. Especially, if the output power of PVPCS equals to power consumption of local loads, it is very difficult for the PVPCS to sustain the voltage and frequency in an island. Unintentional islanding of PVPCS may result in power-quality issues, interference to grid-protection devices, equipment damage, and even personnel safety hazards. So the verification of anti-islanding performance is strongly needed. In this paper, the authors propose the improved RPV method through considering power quality and anti-islanding capacity of grid-connected three-phase PVPCS in IEEE Std 1547 ("Standard for Interconnecting Distributed Resources to Electric Power Systems"). And the simulation and experimental results are verified.

• Asian review of World Histories
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• v.1 no.1
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• pp.5-44
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• 2013

This essay offers a historically based critique of the idea of "alternative modernities" that has acquired popularity in scholarly discussions over the last two decades. While significant in challenging Euro/American-centered conceptualizations of modernity, the idea of "alternative modernities" (or its twin, "multiple modernities") is open to criticism in the sense in which it has acquired currency in academic and political circles. The historical experience of Asian societies suggests that the search for "alternatives" long has been a feature of responses to the challenges of Euromodernity. But whereas "alternative" was conceived earlier in systemic terms, in its most recent version since the 1980s cultural difference has become its most important marker. Adding the adjective "alternative" to modernity has important counter-hegemonic cultural implications, calling for a new understanding of modernity. It also obscures in its fetishization of difference the entrapment of most of the "alternatives" claimed--products of the reconfigurations of global power--within the hegemonic spatial, temporal and developmentalist limits of the modernity they aspire to transcend. Culturally conceived notions of alternatives ignore the common structural context of a globalized capitalism which generates but also sets limits to difference. The seeming obsession with cultural difference, a defining feature of contemporary global modernity, distracts attention from urgent structural questions of social inequality and political injustice that have been globalized with the globalization of the regime of neoliberal capitalism. Interestingly, "the cultural turn" in the problematic of modernity since the 1980s has accompanied this turn in the global political economy during the same period. To be convincing in their claims to "alterity", arguments for "alternative modernities" need to re-articulate issues of cultural difference to their structural context of global capitalism. The goal of the discussion is to work out the implications of these political issues for "revisioning" the history and historiography of modernity.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2009.11a
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• pp.219-224
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• 2009

Construction industry is an important key industry and many measures to revitalize it as local economy has been stagnant. However, construction industry works combined with governmental policies, global and local economies, populations, construction companies and many other related factors, and it is very hard for those counter-plans to meet every need and goal of the related. In this study, interviews and questionnaires of the professionals of the construction industry in Busan, were carried out, to find the cause of the inactivity of the construction market, the problems of the policies and regulations, and the problems of the construction companies in Busan and the solutions were suggested. The realistic master-plans and the reduction of the cost price for the problems of the redevelopment business having no feasibility, the reasonable relaxation of the restrictions for the problems of the governmental policies, the professional training and education for the lack of the high-quality human resources and the working system changes for the problems of the local construction companies turned out as results. The results of the study will be a chance to understand the different ideas of the professionals, and help with the plans to improve and to revitalize the local construction industry. The results of the study will be a chance to understand the different ideas of the professionals, and help with the plans to improve and to revitalize the local construction industry.

• Proceedings of the Korean Geotechical Society Conference
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• 2010.09c
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• pp.3-10
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• 2010

Case study was carried out on the interpretation of the mechanical behavior of a severely damaged reinforced earth wall comprising geotextile with the concrete panel facing. In this part I, the outline of the damaged reinforced earth wall is in detail described. The background and cause of the damage are discussed based on the results of site investigation. The engineering properties of the fill were examined by performing various in-situ and laboratory tests, including the surface wave survey (SWS), PS-logging, RI-logging, soaking test, the direct shear box (DSB) test, bender element (BE) test, etc. The background as well as the cause for the damage of the wall may be described such that i) a considerable amount of settlement took place over a 3m thick weak soil layer in the lower part of the reinforced earth due to seepage of rainfall water, ii) the weight of the upper fill was partially supported by the geo-textile hooked on the concrete panels (n.b., named conveniently "hammock state" in this paper), and iii) the concrete panels to form the hammock were severely damaged by the unexpectedly large downwards compression force triggered by the tension force of the geotextile. The numerical simulation for the hammock state of the wall, together with counter-measures to re- stabilize the wall is subsequently described in Part II.