• Title/Summary/Keyword: MHD

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Earthquake-related Data Selection using Event Packets (이벤트 패킷을 이용한 지진관련 데이터의 추출)

  • Lim, In-Seub;Jung, Soon-Key
    • Journal of the Korea Society of Computer and Information
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    • v.13 no.6
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    • pp.59-68
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    • 2008
  • In this paper, we propose a method for selecting meaningful event packets from which can receive before anything else from seismograph according to allotted priority and estimate epicenter using selected packets. Event packets which received from each station will be evaluated with their onset time, signal period and SNR by statistical method and will be selected packets related with real earthquake's P-wave. And estimated epicenters using by 'Application of epicenter estimation using first P arrivals'. With local earthquakes occurred in 2007 were announced by KMA, collected event packets on earthquake happened date and selected p-wave related packets and estimated epicenter. After result of experiment, if an earthquake occurred within seismic networks, can estimate epicenter with small misfits just after event packets arrived from above 4 stations. Considering average distance of each station, in case of using all stations' data include other organization, can estimate and alert rapidly. It show this method is useful when construct a local earthquake early warning system later.

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A Study on High Power Factor Electronic Ballast for Metal Halide Discharge Lamp Using a Double Resonant Inverter (복공진 인버터를 적용한 고역률 메탈핼라이드 램프용 전자식 안정기에 관한 연구)

  • Park Jae-Wook;Seo Cheol-Sik;Nam Seung-Sik;Kim Hae-Jun;Won Jae-Sun;Kim Dong-Hee
    • The Transactions of the Korean Institute of Power Electronics
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    • v.10 no.4
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    • pp.313-322
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    • 2005
  • In this paper, High power factor electronic ballast using a double resonant Inverter for 250[W] MHD lamp is designed and implemented. Proposed electronic ballast is composed of configuration that is cascaded boost active PFC circuit as power factor corrector and half-bridge double resonant inverter Into two stage approach. Theoretical analysis of circuit and characteristics estimation is generally illustrated by using normalized parameter. To remove the phenomenon of acoustic resonance in the lamp, Simple frequency controller composed timer IC and driving IC is designed and employed on the ballast. The experimental results show that an high power factor electronic ballast using a double resonant inverter is operated stably.

ITER 블랑켓 시험모듈(TBM)의 액체형 증식재 성능 시험용 루프 설계 및 제작

  • Yun, Jae-Seong;Lee, Dong-Won;Bae, Yeong-Deok;Kim, Seok-Gwon;Hong, Bong-Geun
    • Proceedings of the Korean Vacuum Society Conference
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    • 2010.02a
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    • pp.281-281
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    • 2010
  • ITER 블랑켓 시험모듈(TBM)의 액체형 증식재 성능 시험용 루프의 설계를 완료하였고 현재시험용 루프를 제작 및 설치중이다. 액체형 증식재 성능 시험용 루프의 핵심 구성 부품인 액체 저장용 탱크, 전자석, EM 펌프들과 이들 장치들의 전원장치 및 제어장치를 제작 완료하였다. 액체형 증식재 성능 시험용 루프 설치를 위한 데크를 제작하였으며, 제작된 실험 데크의 총 지지하중은 10 톤 이상이다. 루프설치대 위에 성능 시험용 루프가 설치되며 루프 설치대는 $3\;m\;{\times}\;2.4\;m$ 의 직사각형으로 제작되었으며, 실험 종료 및 유지 보수 시 액체증식재의 drain을 고려하여 전체 루프는 각도 조절이 가능하도록 제작되었다. 루프내의 유량을 측정하기 위한 유량계, 전자석 자장의 변화에 따른 압력의 변화를 측정하기 위한 차압센서가 전자석의 양단에 설치되며, 시험용 루프에 흐르는 액체금속(PbLi) 및 루프관의 온도를 측정하기 위한 열전대가 설치된다. 루프 설치대를 기울였을 때 루프의 최상부에 액체금속 저장고 및 레벨센서를 설치하여 루프 내에 액체금속이 가득 채워졌는지를 레벨센서로 확인하며 루프 내에 잔존하는 기체가 저장고를 통하여 외부로 배출되게 하였다. 액체형 증식재 성능 시험용 루프 설치 후 실험은 고체 상태의 PbLi를 액체 저장용 탱크에 장착한 후 탱크의 열선의 온도 제어에 의한 PbLi의 용융점 확인, 시험용 루프에서의 전자펌프 성능 평가 등의 시험의 기본적인 실험을 수행한 후 자기장 환경에서 MHD 평가, 증식재의 순도 유지, 구조재의 부식 등의 시험을 수행할 예정이다.

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Evolution of particle acceleration and instabilities in galaxy cluster shocks

  • van Marle, Allard Jan;Ryu, Dongsu;Kang, Hyesung;Ha, Ji-Hoon
    • The Bulletin of The Korean Astronomical Society
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    • v.43 no.2
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    • pp.42.2-43
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    • 2018
  • When galaxy clusters interact, the intergalactic gas collides, forming shocks that are characterized by a low sonic Mach number (~3) but a comparatively high Alfvenic Mach number (~30). Such shocks behave differently from the more common astrophysical shocks, which tend to have higher sonic Mach numbers. We wish to determine whether these shocks, despite their low sonic Mach number, are capable of accelerating particles and thereby contributing to the cosmic ray spectrum. Using the PIC-MHD method, which separates the gas into a thermal and a non-thermal component to increase computational efficiency, and relying on existing PIC simulations to determine the rate at which non-thermal particles are injected in the shock, we investigate the evolution of galaxy cluster shocks and their ability to accelerate particles. Depending on the chosen injection fraction of non-thermal particles into the shock, we find that even low-Mach shocks are capable of accelerating particles. However, the interaction between supra-thermal particles and the local magnetic field triggers instabilities and turbulence in the magnetic field. This causes the shock to weaken, which in turn reduces the effectiveness of the supra-thermal particle injection. We investigate how this influences the shock evolution by reducing the particle injection rate and energy and find that a reduction of the particle injection fraction at this stage causes an immediate reduction of both upstream and downstream instabilities. This inhibits particle acceleration. Over time, as the instabilities fade, the shock surface straightens, allowing the shock to recover. Eventually, we would expect this to increase the efficiency of the particle injection and acceleration to previous levels, starting the same series of events in an ongoing cycle of increasing and decreasing particle acceleration.

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Probabilities of Pulmonary and Cardiac Complications and Radiographic Parameters in Breast Cancer Radiotherapy (유방암의 방사선치료에서 방사선학적 지표에 따른 폐 및 심장의 부작용 확률)

  • Noh, O-Kyu;Park, Sung-Ho;Ahn, Seung-Do;Choi, Eun-Kyung;Lee, Sang-Wook;Song, Si-Yeol;Yoon, Sang-Min;Kim, Jong-Hoon
    • Radiation Oncology Journal
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    • v.28 no.1
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    • pp.23-31
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    • 2010
  • Purpose: To evaluate the relationship between the normal tissue complication probability (NTCP) of 3-dimensional (3-D) radiotherapy and the radiographic parameters of 2-dimensional (2-D) radiotherapy such as central lung distance (CLD) and maximal heart distance (MHD). Materials and Methods: We analyzed 110 patients who were treated with postoperative radiotherapy for breast cancer. A two-field tangential technique, a three-field technique, and the reverse hockey stick method were used. The radiation dose administered to whole breast or the chest wall was 50.4 Gy, whereas a 45 Gy was administered to the supraclavicular field. The NTCPs of the heart and lung were calculated by the modified Lyman model and the relative seriality model. Results: For all patients, the NTCPs of radiation-induced pneumonitis and cardiac mortality were 0.5% and 0.7%, respectively. The NTCP of radiation-induced pneumonitis was higher in patients treated with the reverse hockey stick method than in those treated by other two techniques (0.0%, 0.0%, 3.1%, p<0.001). The NTCP of radiation-induced pneumonitis increased with CLD. The NTCP of cardiac mortality increased with MHD ($R^2=0.808$). Conclusion: We found a close correlation between the NTCP of 3-D radiotherapy and 2-D radiographic parameters. Our results are useful to reanalyze the previous 2-D based clinical reports about breast radiation therapy complications as a viewpoint of NTCP.

A Dosimetric Evaluation of Large Pendulous Breast Irradiation in Prone Position (Large Pendulous Breast 환자의 방사선 치료에 있어서 엎드린 자세의 유용성 평가)

  • Hong, Chae-Seon;Ju, Sang-Gyu;Park, Ju-Young
    • The Journal of Korean Society for Radiation Therapy
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    • v.20 no.1
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    • pp.37-43
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    • 2008
  • Purpose: To evaluate dosimetry results of three different techniques for whole breast irradiation after conservative surgery of large pendulous breast patient. Materials and Methods: Planning computed tomography (CT) scans for three techniques were performed on a GE Hi-speed advantage CT scanner in the supine (SP), supine with breast supporting Device (SD) and prone position on a custom prone mattress (PP). Computed tomography images were acquired at 5 mm thickness. The clinical target volumes (CTV), ipsilateral lung and heart were delineated to evaluate the dose statistic, and all techniques were planned with the tangential photon beams (Pinnacle$^3$, Philips Medical System, USA). The prescribed dose was 50 Gy delivered in 25 fractions. To evaluate the dose coverage for CTV, we analysed percent volume of CTV receiving minimum of 95%, 100%, 105%, and 110% of prescription dose ($V_{95}$, $V_{100}$, $V_{105}$, and $V_{110}$) and minimal dose covering 95% ($D_{95}$) of CTV. The dosimetric comparison for heart and ipsilateral lung was analysed using the minimal dose covering 5% of each organs ($D_5$) and the volume that received >18 Gy for the heart and >20 Gy for the ipsilateral lung. Results: Target volume coverage ($V_{95}$ and $V_{100}$) was not significantly different for all technique. The V105 was lower for PP (1.2% vs. 4.4% for SP, 11.1% for SD). Minimal dose covering 95% ($D_{95}$) of target was 47.5 Gy, 47.7 Gy and 48 Gy for SP, SD and PP. The volume of ipsilateral lung received >20 Gy was 21.7%, 11.6% and 4.9% for SP, SD and PP. The volume of heart received >18 Gy was 17.0%, 16.1% and 9.8% for SP, SD and PP. Conclusion: Prone positioning of patient for large pendulous breast irradiation enables improving dose uniformity with minimal heart and lung doses.

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Optimum design analysis of ICP(Inductively Coupled Plasma) torch for high enthalpy thermal plasma flow (고엔탈피 열유동 발생용 고주파 유도결합 플라즈마 토치의 최적 설계변수 해석)

  • Seo, Jun-Ho
    • Journal of the Korean Society for Aeronautical & Space Sciences
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    • v.40 no.4
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    • pp.316-329
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    • 2012
  • In this paper, optimum design process of ICP (Inductively Coupled Plasma) torch, which has been used widely in aerospace application, such as supersonic plasma wind tunnel, is presented. For this purpose, the behaviors of equivalent circuit parameters (equivalent resistance and inductance, coupling efficiency) were investigated according to the variations of torch design parameters (frequency, $f$, confinement tube radius, $R$ and coil turn numbers, $N$) in the basis of analytical and numerical MHD (Magneto Hydro-Dynamics) models combined with electrical circuit theory. From the results, it is found that equivalent resistance is increased with the increase of $f$ values but vice versa for equivalent inductance. For elevated values of $R$ and $N$, however, both parameters tend to increase. Based on these observations, ICP torch with a power level of 10 kW can be optimized at the design ranges of $f$=4~6 MHz, $R$=17~25 mm and $N$=3~4 to maximize the electrical coupling efficiency, which is the ratio of equivalent resistance to equivalent inductance.

Simultaneous Spectrophotometric Determination of Copper, Nickel, and Zinc Using 1-(2-Thiazolylazo)-2-Naphthol in the Presence of Triton X-100 Using Chemometric Methods (화학계량학적 방법을 사용한 Triton X-100이 함유된 1-(2-Thiazolylazo)-2-Naphthol을 사용한 구리, 니켈과 아연의 동시 분광광도법적 정량)

  • Low, Kah Hin;Zain, Sharifuddin Md.;Abas, Mhd. Radzi;Misran, Misni;Mohd, Mustafa Ali
    • Journal of the Korean Chemical Society
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    • v.53 no.6
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    • pp.717-726
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    • 2009
  • Multivariate models were developed for the simultaneous spectrophotometric determination of copper (II), nickel (II) and zinc (II) in water with 1-(2-thiazolylazo)-2-naphthol as chromogenic reagent in the presence of Triton X-100. To overcome the drawback of spectral interferences, principal component regression (PCR) and partial least square (PLS) multivariate calibration approaches were applied. Performances were validated with several test sets, and their results were then compared. In general, no significant difference in analytical performance between PLS and PCR models. The root mean square error of prediction (RMSEP) using three components for $Cu^{2+}$, $Ni^{2+}$ and $Zn^{2+}$ were 0.018, 0.010, 0.011 ppm, respectively. Figures of merit such as sensitivity, analytical sensitivity, limit of detection (LOD) were also estimated. High reliability was achieved when the proposed procedure was applied to simultaneous determination of $Cu^{2+}$, $Ni^{2+}$ and $Zn^{2+}$ in synthetic mixture and tap water.

Sequence variation of necdin gene in Bovidae

  • Peters, Sunday O.;Donato, Marcos De;Hussain, Tanveer;Rodulfo, Hectorina;Babar, Masroor E.;Imumorin, Ikhide G.
    • Journal of Animal Science and Technology
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    • v.60 no.12
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    • pp.32.1-32.10
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    • 2018
  • Background: Necdin (NDN), a member of the melanoma antigen family showing imprinted pattern of expression, has been implicated as causing Prader-Willi symptoms, and known to participate in cellular growth, cellular migration and differentiation. The region where NDN is located has been associated to QTLs affecting reproduction and early growth in cattle, but location and functional analysis of the molecular mechanisms have not been established. Methods: Here we report the sequence variation of the entire coding sequence from 72 samples of cattle, yak, buffalo, goat and sheep, and discuss its variation in Bovidae. Median-joining network analysis was used to analyze the variation found in the species. Synonymous and non-synonymous substitution rates were determined for the analysis of all the polymorphic sites. Phylogenetic analysis were carried out among the species of Bovidae to reconstruct their relationships. Results: From the phylogenetic analysis with the consensus sequences of the studied Bovidae species, we found that only 11 of the 26 nucleotide changes that differentiate them produced amino acid changes. All the SNPs found in the cattle breeds were novel and showed similar percentages of nucleotides with non-synonymous substitutions at the N-terminal, MHD and C-terminal (12.3, 12.8 and 12.5%, respectively), and were much higher than the percentage of synonymous substitutions (2.5, 2.6 and 4.9%, respectively). Three mutations in cattle and one in sheep, detected in heterozygous individuals were predicted to be deleterious. Additionally, the analysis of the biochemical characteristics in the most common form of the proteins in each species show very little difference in molecular weight, pI, net charge, instability index, aliphatic index and GRAVY (Table 4) in the Bovidae species, except for sheep, which had a higher molecular weight, instability index and GRAVY. Conclusions: There is sufficient variation in this gene within and among the studied species, and because NDN carry key functions in the organism, it can have effects in economically important traits in the production of these species. NDN sequence is phylogenetically informative in this group, thus we propose this gene as a phylogenetic marker to study the evolution and conservation in Bovidae.

"Critical Application of Witness Commentaries: The Case of Guerrilla Warfare in the Korean War" ("증언자료의 비판적 활용 - 6.25전쟁 시기 유격대의 경우")

  • Cho, Sung Hun
    • The Korean Journal of Archival Studies
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    • no.12
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    • pp.137-178
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    • 2005
  • The anticommunist guerrillas' activities that aretheconcern of this article took place largely in North Korea or behind the enemy-held lines. Verifying their history is accordingly difficult and requires careful attention, but despite their active operations the military as well as the scholarly community have been lax in studying them. The Korean War came to be perceived as a traditional, limited war with regular battles, so that the studies addressed mostly the regular operations, and guerrilla warfare is remembered as an almost 'exclusive property' of the communist invaders; a small wonder that the anticommunist guerrillas have not been studied much and the collection of materials neglected. Therefore, in contrast with the witness accounts concerning regular battles, witness resources were of a small volume about these "patriots without the service numbers." For the above reasons the guerrilla participants and their later-organized fellowships took to the task of leaving records and compiling the histories of their units. They became active preservers of history in order to inform later generations of their works and also to secure deserved benefits from the government, in a world where none recognized their achievements. For instance, 4th Donkey Unit published witness accounts in addition to a unit history, and left video-recordings of guerrilla witnesses before any institute systematized the oral history of the guerrillas. In the case of Kyulsa ("Resolved to Die") Guerrilla Unit, the unit history was 10 times revised and expanded upon for publication, contributing substantially to the recovery of anticommunist guerrilla history which had almost totally lacked documented resources. Now because the guerrilla-related witness accounts were produced through fellowship societies and not individually, it often took the form of 'collective memory.' As a result, though thousands of former guerrillas remain surviving, the scarcity of numerous versions of, or perspectives upon, an event renders difficult an objective approach to the historical truth. Even requests to verify the service of a guerrilla member or to apply for decoration or government benefits for those killed in action, the process is taken care of not at the hands of the first party but the veteran society, so that a variety of opinions are not available for consideration. Moreover, some accounts were taken by American military personnel, and since some historians, unaware of official documents or evaluation of achievements, tended to center the records around their own units and especially to exaggerate the units' performances, they often featured factual errors. Thefollowing is the means to utilize positively the aforementioned type of witness accounts in military history research. It involves the active use of military historical detachments (MHD). As in the examples of those dispatched by the American forces during the Korean War, experts should be dispatched during, and not just after, wartimes. By considering and investigating the differences among various perspectives on the same historical event, even without extra documented resources it is possibleto arrive at theerrors or questionable points of the oral accounts, supplementing the additional accounts. Therefore any time lapses between witness accounts must be kept in consideration. Moreover when the oral accounts come from a group such as participants in the same guerrilla unit or operation, a standardized list of items ought to be put to use. Education in oral history is necessary not just for the training of experts. In America wherethefield sees much activity, it is used not only in college or graduate programs but also in elementary and lifetime educational processes. In comparison in our nation, and especially in historical disciplines, methodological insistence upon documented evidences prevails in the main, and in the fields of nationalist movement or modern history, oral accounts do not receive adequate attention. Like ancient documents and monuments, oral history also needs to be made a regular part of diverse resource materials at our academic institutes for history. Courses in memory and history, such as those in American colleges, are available possibilities.