• Title/Summary/Keyword: ATHENA

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Development and validation of the lead-bismuth cooled reactor system code based on a fully implicit homogeneous flow model

  • Ge Li;Wang Jingxin;Fan Kun;Zhang Jie;Shan Jianqiang
    • Nuclear Engineering and Technology
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    • v.56 no.4
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    • pp.1213-1224
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    • 2024
  • The liquid lead-bismuth cooled fast reactor has been in a single-phase, low-pressure, and high-temperature state for a long time during operation. Considering the requirement of calculation efficiency for long-term transient accident calculation, based on a homogeneous hydrodynamic model, one-dimensional heat conduction model, coolant flow and heat transfer model, neutron kinetics model, coolant and material properties model, this study used the fully implicit difference scheme algorithm of the convection-diffusion term to solve the basic conservation equation, to develop the transient analysis program NUSOL-LMR 2.0 for the lead-bismuth fast reactor system. The steady-state and typical design basis accidents (including reactivity introduction, loss of flow caused by main pump idling, excessive cooling, and plant power outage accidents) for the ABR have been analyzed. The results are compared with the international system analysis software ATHENA. The results indicate that the developed program can stably, accurately, and efficiently predict the transient accident response and safety characteristics of the lead-bismuth fast reactor system.

Cultural Diversity of Kushan Empire Through Die Analysis of the Depicted Costumes of Artifacts of Tillya Tepe (틸랴 테페 유물의 복식분석을 통해본 쿠샨왕조 문화의 다양성)

  • Chang, Youngsoo
    • Journal of Fashion Business
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    • v.24 no.5
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    • pp.158-176
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    • 2020
  • The purpose of this study was to examine the cultural diversity in terms of costumes by analyzing the costumes depicted in the early Kushan Dynasty relics, Tillya Tepe. As a research method, literature research and artifact analysis were conducted in parallel. The type of costume worn by the king (or priest) was in the type of a jacket and skirt, which was thought to be of Persian influence. The Greek god of Dionysos was wearing a costume with Danryong (團領) and narrow sleeves, a nomadic type of Central Asia. It could be seen that costumes were transformed into indigenous elements of the region. The shape of the helmet worn by the warrior was a Greek-Macedonian helmet. However, details were transformed into indigenous elements of the Kushan dynasty. The clothing of a nobleman riding a carriage was an element of dress that was observed in Chinese po(袍), and was an unusual element not found in nomadic peoples. There were goddesses wearing Greek robes like Aphrodite in Tillya Tepe's relics. On the other hand, there were goddesses who did not wear Greek chitons like the Greek goddess Athena. Instead, they wore high-waisted robes worn by the Orient goddesses. In addition, after Kushan occupied India, there were Indian elements believed to be expressed by accepting Indian culture. These elements were combined with regional orient elements of the Kushan dynasty, Central Asian elements, and Kushan's own elements. Thus cultural diversity emerged in the costumes depicted in Tillya Tepe artifacts.

A effect of the back contact silicon solar cell with surface texturing size and density (표면 텍스쳐링 크기와 밀도가 후면 전극 실리콘 태양전지에 미치는 영향)

  • Jang, Wanggeun;Jang, Yunseok;Pak, Jungho
    • 한국신재생에너지학회:학술대회논문집
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    • 2011.05a
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    • pp.112.1-112.1
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    • 2011
  • The back contact solar cell (BCSC) has several advantages compared to the conventional solar cell since it can reduce grid shadowing loss and contact resistance between the electrode and the silicon substrate. This paper presents the effect of the surface texturing of the silicon BCSC by varying the texturing depth or the texturing gap in the commercially available simulation software, ATHENA and ATLAS of the company SILVACO. The texturing depth was varied from $5{\mu}m$ to $150{\mu}m$ and the texturing gap was varied from $1{\mu}m$ to $100{\mu}m$ in the simulation. The resulting efficiency of the silicon BCSC was evaluated depending on the texturing condition. The quantum efficiency and the I-V curve of the designed silicon BCSC was also obtained for the analysis since they are closely related with the solar cell efficiency. Other parameters of the simulated silicon BCSC are as follows. The substrate was an n-type silicon, which was doped with phosphorous at $6{\times}10^{15}cm^{-3}$, and its thickness was $180{\mu}m$, a typical thickness of commercial solar cell substrate thickness. The back surface field (BSF) was $1{\times}10^{20}\;cm^{-3}$ and the doping concentration of a boron doped emitter was $8.5{\times}10^{19}\;cm^{-3}$. The pitch of the silicon BCSC was $1250{\mu}m$ and the anti-reflection coating (ARC) SiN thickness was $0.079{\mu}m$. It was assumed that the texturing was anisotropic etching of crystalline silicon, resulting in texturing angle of 54.7 degrees. The best efficiency was 25.6264% when texturing depth was $50{\mu}m$ with zero texturing gap in case of low texturing depth (< $100{\mu}m$).

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Towards a Dialogic Approach: Crisis Communications and Public Reactions in the World's Most Densely Populated City to Tackle COVID-19

  • Yuncg, Juliana Qi Xuan;Cheong, Angus Weng Hin;Seng, Athena I No;Li, Kim Jing
    • Asian Journal for Public Opinion Research
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    • v.8 no.3
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    • pp.265-296
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    • 2020
  • Macao, a special administrative region of China, has been able to maintain the records of zero deaths and keep confirmed cases under 50 since the outbreak of COVID-19 for more than half a year as of July 2020, despite being the world's most densely populated city. The current paper utilizes the dialogic public relations theory to analyze the situation using both literature review on how the various government actions and strategies during the pandemic were corresponding to the theory, and a quantitative random digital dialing (RDD) telephone survey, with a sample of 502 Macao residents aged 18 or above, to study the public reactions towards the government pandemic prevention actions. Survey results show a high level of public satisfaction towards epidemic prevention performance, as well as some forms of collaborative information redissemination behavior in social media platforms. Literature review and analysis from dialogic theory found that spirit of mutual equality, collaboration with local community, immediacy of presence in crisis time, engagements with stakeholders through maximum media channels and networks, supportiveness to public with both useful information and practical social support like subsidy program, as well as commitment to transparent and genuine communication, are all the dialogic communications strategies that describe what the Macao government has done in the crisis of COVID-19. The dialogic strategies that could be learned from the Macao government may be used as a reference for similar urbanized and densely populated cities in other territories.

Work and Travel Experiences of Filipino Tourism Students in Selected Universities

  • Carpio, Geneive Joie;Torres, Athena Louise De;Samiran, Rinna;Villera, Kaselyn Joyce;Manguerra-Mahusay, Sharon
    • Asian Journal for Public Opinion Research
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    • v.5 no.2
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    • pp.143-174
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    • 2018
  • A cultural exchange program widens the horizons of students. It gives them the opportunity to associate with other societies and learn their cultures at the same time. This program also serves as a training ground where students enhance their skills, acquire learnings, and gain experiences that will help them in their future careers and make them more competitive than others. Hence, the objective of this study is to come up with an output from a set of guidelines established and gathered from the different "work and travel" experiences of the participants. This study adopted the phenomenological and was conducted in places that are relatively quiet for recording, and suitable and convenient for both the researchers and participants. The researchers gathered data through in-depth interviews of samples gathered through snowball sampling. Cellphones were used to record interviews. At the end of the thematic analysis of information, the researchers came up with three major categories which included: (1) 'having the opportunity to know the industry well and improve one's capability', 'undergoing different cultural exchange experiences for better development', and 'being able to practice intercultural immersion'. Some of the researchers' recommendations would be to institute a feedback mechanism such as personal interviews, monitoring visits, etc. and use the output, a set of guidelines, that would help the future 'work and travel' participants to prepare and anticipate the program they would undergo.

History and Development Status of Aegis Ships (이지스함의 역사와 발전 현황)

  • Go, Kyung-min;Jeon, Eun-seon;Park, Tae-yong
    • Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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    • 2015.10a
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    • pp.433-435
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    • 2015
  • Aegis Combat System(ACS) is a shipboard combat system developed by U.S. Navy. Its name, Aegis, came from a shield 'Aegis' in greek mythology, which Zeus gave to his daughter Athena. U.S. Navy uses Aegis ships(ships which mount ACS) as their main surface forces. It is known as one of the greatest anti-air warfare ship in the world by its ability to detect air threats with AN/SPY-1, phased array radar, superior Target management and command and control capabilities of the combat system, and SM series interceptors. After first Aegis cruiser USS Ticonderoga was deployed at 1983, U.S. Navy continuously put effort in developing Aegis Combat Systems and Aegis ships. They also improve old fashion existing ships by modernize them. In this Paper, to deduct a lesson which Korea Navy should benchmark, it is went through that a history of Aegis ships and development of ACS, and also its feature.

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Simulation study of ion-implanted 4H-SiC p-n diodes (이온주입 공정을 이용한 4H-SiC p-n diode에 관한 시뮬레이션 연구)

  • Lee, Jae-Sang;Bahng, Wook;Kim, Sang-Cheol;Kim, Nam-Kyun;Koo, Sang-Mo
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • 2008.06a
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    • pp.131-131
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    • 2008
  • Silicon carbide (SiC) has attracted significant attention for high frequency, high temperature and high power devices due to its superior properties such as the large band gap, high breakdown electric field, high saturation velocity and high thermal conductivity. We performed Al ion implantation processes on n-type 4H-SiC substrate using a SILVACO ATHENA numerical simulator. The ion implantation model used a Monte-Carlo method. We studied the effect of channeling by Al implantation simulation in both 0 off-axis and 8 off-axis n-type 4H-SiC substrate. We have investigated the Al distribution in 4H-SiC through the variation of the implantation energies and the corresponding ratio of the doses. The implantation energies controlled 40, 60, 80, 100 and 120 keV and the implantation doses varied from $2\times10^{14}$ to $1\times10^{15}cm^{-2}$. In the simulation results, the Al ion distribution was deeper as increasing implantation energy and the doping level increased as increasing implantation doses. After the post-implantation annealing, the electrical properties of Al-implanted p-n junction diode were investigated by SILV ACO ATLAS numerical simulator.

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Simulation of Threshold Voltages for Charge Trap Type SONOS Memory Devices as a Function of the Memory States (기억상태에 따른 전하트랩형 SONOS 메모리 소자의 문턱전압 시뮬레이션)

  • Kim, Byung-Cheul;Kim, Hyun-Duk;Kim, Joo-Yeon
    • Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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    • v.9 no.1
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    • pp.981-984
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    • 2005
  • This study is to realize its threshold voltage shift after programming operation in charge trap type SONOS memory by simulation. SONOS devices are charge trap type nonvolatile memory devices in which charge storage takes place in traps in the nitride-blocking oxide interface and the nitride layer. For simulation of their threshold voltage as a function of the memory states, traps in the nitride layer have to be defined. However, trap models in the nitride layer are not developed in commercial simulator. So, we propose a new method that can simulate their threshold voltage shift by an amount of charges induced to the electrodes as a function of a programming voltages and times as define two electrodes in the tunnel oxide-nitride interface and the nitride-blocking oxide interface of SONOS structures.

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Ideology, Politics, and Social Science Scholarship on the Responsibility of Intellectuals

  • Koerner, E.F.K.
    • Lingua Humanitatis
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    • v.2 no.2
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    • pp.51-84
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    • 2002
  • The 1990s have seen the publication of many books devoted to Language and Ideology (cf. Joseph & Taylor 1990. for one of the early ones) even though the term 'ideology' itself has remained ill-defined (Woolard 1998). The focus of attention has usually been placed on the particular use of language and often for some kind of 'political' ends, not on linguistic or other scholarship which might have been driven by some sort of ideology, i.e., a bundle of assumptions which themselves were taken as given. At least since Edward Said's 1978 book Orientalism, it has been clear to everyone that scholars construct their conceptualization of things in line with their understanding of the cultural, social, and political world in which they live, and that this often unreflected 'pre-understanding' effects their view of cultures that are different from theirs and more often than not geographically and temporally distant from theirs. This recognition has had a sobering effect no doubt, and Said's book has long since become 'mainstream.' Much more disturbing to the scholarly profession has been the publication of Martin Bernal's Black Athena in 1987, since it went much further, going beyond accusations of colonialism and cultural bias, in suggesting that the Western representation of Classical Greece over the past two hundred years was false and that what had been accepted until now about occidental antiquity must now be seen derived from African-Asiatic cultures of the Near East, notably that of the Ancient Egyptians, and that no other than Socrates should be seen as black man. While we may understand the intellectual climate in the United States that led academics to present 'myth as history' (Lefkowitz 1996), it is obvious that lines of regular scholarly principles of investigation have been crossed (cf Lefkowitz & Rogers 1996). The present paper investigates what may be seen as the ideological underpinnings of such work. After reviewing some recent scholarship in the area of linguistic historiography that have shown that academic work has never been 'value-neutral' (as may have been assumed or has been claimed by some practitioners), it is argued that in effect one must be aware of what Clemens Knobloch has recently termed Resonanzbedarf, i.e., the desire, whether conscious or not, of scholars-and probably scientists, too-to have their work recognized by the educated public and that, in so doing, their discourses tend to pick up on contemporary popular notions. These efforts may be harmless if everyone was to recognize these allusions and adoption of certain lexical. items(buzz words) as props or what Germans call Versatzstiicke, but history tells us that this has not always been the case. Still, as Hutton (1999) has shown, not all scholarship during the Third Reich for example can simply be dismissed as worthless because it was conducted in under a prevailing political ideology. Indeed, in seemingly innocent times, linguists can be shown to frame their argument in a way that makes them appear so utterly superior to their predecessors (cf. Lawson 2001). Upon closer inspection, those discourses turn out to be much like those of scholars in nationalistic environments that have tended to select their 'facts' to prove a particular hypothesis (cf., e.g., Koerner 2001). The article argues for scholars to take a more active role in exploding myths, scientifically unfounded claims, and ideologically driven distortions, especially those that are socially and politically harmful.

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