• 방사성폐기물학회지
• /
• 제3권4호
• /
• pp.301-307
• /
• 2005

조사후 핵연료 가열(PIA장비)를 이용한 고연소도 UO2 사용후 핵연료의 산화 및 가열후 미세조직의 변화를 관찰하였다. 울진 2호기에서 한국원자력연구소 조사후시험시설로 이송된 국산 경수로용 고연소도 사용후 핵연료는 봉평균 연소도가 57,000 MWd/tU-rod avg.이였다. 본 시험에 사용된 시편은 국부연소도 65,000 MWd/tU UO2 소결체의 고형체 200 mg을 사용하였다. 본 시편을 사용후 핵 연료 가열(PIA) 시험장비를 이용하여 핫셀 내에서 3시간의 산화시험과 연속적으로 $1,400^{\circ}C$ 까지 가열하였다. 결정립경계까지의 산화를 위하여 $500^{\circ}C$에서 헬륨 50 ml, 표준공기 100 ml를 흔합한 산화분위기로 3시간을 유지하였다. 핵분열기체 방출거동을 알기위해 시험 전과정중에 85Kr의 방출량을 베타 측정기와 감마 측정기를 이용하여 실시간으로 측정 하였다. 가열시험이 종료된 후 전자주사현미경을 이용하여 미세구조의 변화를 관찰하였다. 시험결과 가열하는 동안 핵분열생성물은 UO2기지의 결정립경계와 표면으로 이동된 것을 관찰하였다. 이 시편은 환원과정을 통하여 재구조화 되었고, $5\~10\;{\mu}m$ 정도의 결정립크기를 가진 것으로 나타났다.

• 비교문화연구
• /
• 제51권
• /
• pp.161-191
• /
• 2018

20세기 들어 서구중심적 보편주의에 직접적으로 의문을 제기한 지적 흐름은 이른바 '탈식민주의(Postcolonialisme)이다. 지금까지 제시된 탈식민주의 비평의 주요 성과 가운데 하나는 피식민사회의 정치적 해방이 해당 사회의 경제, 사회, 문화 등의 해방을 담보하지 못하고, 따라서 서구사회의 해방담론- 특히 맑스주의, 민족주의, 여성주의, 해체주의 등이 주창해온 -이 비서구사회에 직접적으로 적용될 수 없다는 사실이다. 이로 인해 서구사회와 비서구사회는 안타깝게도 서로 다른 미래와 해방을 꿈꾸고 있으며, 따라서 이들 사이에 소위 '지정학적 대화'가 요구된다는 당위성이 노출되었다. 그러나 탈식민적 해방을 위한 이론가들의 노력은 여러 서구중심적인 전통들과 결별하지 못한 채, 혹은 그것들과 연대하면서, 자신들의 세력권을 구축해온 것도 사실- 그 성과를 폄훼하는 것은 아니지만 -이다. 주지하다시피 탈식민주의 비평의 상당수는, 특히 탈식민주의를 주창하거나 제안하는 '화자(話者)' 혹은 '정체성'의 측면에서, 그러한 탈식민주의 이데올로기를 담아내거나 표출하는 '언어(言語)'의 측면에서 그리고 식민적 폐해를 고발함과 동시에 탈식민적 미래를 모색하기 위해 동원하였던 '대항담론(對抗談論)'의 측면에서 어떻게든 서구와의 연을 이어갔다. 본 연구는 피식민사회의 해방을 제안한 여러 탈식민주의 비평들 가운데 이른바 '네그리튀드($N{\acute{e}}gritude$)'운동의 아버지라 불리는 에메 세제르($Aim{\acute{e}}$ $C{\acute{e}}saire$)의 탈식민주의 정치사상을 중심으로 다시 읽기를 추진해볼 것이다. 그것은 세제르의 탈식민주의 정치사상을 '화자', '언어' 그리고 '대항담론'이라는 세 가지 앵글을 통해서 이론적으로 되짚어보는 과정을 의미한다. 이 과정을 통해 세제르와 그의 정치사상을 새롭게 성찰해 볼 수 있는 계기가 되기를 희망해본다.

• 한국방재학회 논문집
• /
• 제4권1호
• /
• pp.51-56
• /
• 2004

본 연구는 전형적인 도심소재 중 소하천인 오산천 상류를 중심으로 수질변화 현상을 정확히 파악하기 위하여 24시간에 걸친 연속측정을 통해 수질의 변화를 조사하였고, 이러한 결과를 통하여 효율적인 하천관리 방향을 제시하였다. 오산천 수질의 연속조사의 결과로부터, 본류의 수질개선을 위해서는 다음과 같은 일들이 선행되어야 할 것으로 판단된다. 첫째, 본류 수질개선을 위해서는 유입지류의 효율적인 관리방안이 필요하다. 둘째, 하천 본류의 저질로부터 재용출 되는 오염을 방지하기 위한 대처방안이 필요하다. 본 연구에서는 수질저하를 방지하기 위해 단순한 조사만으로도 중 소하천의 효과적인 관리 방안을 제시했다. 따라서 하천에서의 연속적인 수질 모니터링은 하천수질 개선을 위해 중요하며, 나아가 하천환경에서 일어나는 물질순환 및 물질수지는 건전한 하천조성을 위하여 정확히 평가되어야 한다.

• 대한기계학회논문집B
• /
• 제29권5호
• /
• pp.577-589
• /
• 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.

• 한국환경복원기술학회지
• /
• 제12권2호
• /
• pp.61-72
• /
• 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
• /
• 제31권3호
• /
• pp.79-85
• /
• 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.

• 대한전기학회:학술대회논문집
• /
• 대한전기학회 2006년도 제37회 하계학술대회 논문집 B
• /
• pp.1159-1160
• /
• 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
• /
• 제1권1호
• /
• pp.5-44
• /
• 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.

• 한국건축시공학회:학술대회논문집
• /
• 한국건축시공학회 2009년도 추계 학술논문 발표대회
• /
• pp.219-224
• /
• 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.

• 한국지반공학회:학술대회논문집
• /
• 한국지반공학회 2010년도 추계 학술발표회 3차
• /
• pp.3-10
• /
• 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.