• 제목/요약/키워드: E-LEACH

검색결과 32건 처리시간 0.027초

계층형 무선센서네트워크를 위한 분리된 이중화 라우팅 (Separated Dual-layering Routing Scheme (SDRS) for Hierarchical Wireless Sensor Networks)

  • 최해원;김경준;김현성
    • 한국항행학회논문지
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    • 제13권4호
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    • pp.551-558
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    • 2009
  • 에너지 효율성 초점이 맞추어진 대부분의 클러스터링 기법에서 클러스터 내에서 단일의 클러스터를 채용함으로써 클러스터 헤드의 에너지 소비가 급격히 증가 할 수 있다. 최근, 이러한 단점을 개선하기 위해 데이터 병합 기능 헤드와 데이터 전송 기능 헤드로 구분하는 2-계층 클러스터 기법은 클러스터 내에서 클러스터 헤드의 에너지 소비를 분산시켰다. 그러나 이러한 구조는 한 클러스터 내에 존재하는 두 개 헤드 사이에 독립적인 영역구분이 없는 단지 논리적인 영역이므로 많은 메시지 충돌과 전송 지연이 발생한다. 이러한 문제점을 해결하기 위해, 본 논문에서는 노드의 위치정보와 클러스터 반경을 이용해 한 클러스터에 속한 두 계층을 독립적으로 명확히 분할할 수 있는 분리된 2-계층 라우팅기법을 제시한다. 제안하는 스킴에서는 각 계층에 속하는 멤버노드 수에 대한 균등분포를 통해 부하의 분산을 보장한다. 제안한 기법은 기존의 DLS 기법보다 메시지 충돌문제를 50% 개선하였고, 네트워크의 수명도 DLS와 LEACH 등에 비해 약 10% 개선하였다.

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Glass Formulations for Vitrification of Low- and Intermediate-level Waste

  • Kim, Cheon-Woo;Park, Jong-Kil;Ha, Jong-Hyun;Song, Myung-Jae;Lee, Nel-Son;Kong, Peter-C.;Anderson, Gary-L.
    • 한국세라믹학회지
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    • 제40권10호
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    • pp.936-942
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    • 2003
  • In order to develop glass formulations for vitrifying Low-and Intermediate-Level radioactive Wastes (LILW) from nuclear power plants of Korea Hydro & Nuclear Power (KHNP) Co., Ltd., promising glass formulations were selected based on glass property model predictions for viscosity, electrical conductivity and leach resistance. Laboratory measurements were conducted to verify the model predictions. Based on the results, the models for electrical conductivity, US DOE 7-day Product Consistency Test (PCT) elemental release, and pH of PCT leachate are accurate for the LILW glass formulations. However, the model for viscosity was able to provide only qualitative results. A leachate conductivity test was conducted on several samples to estimate glass leach resistance. Test results from the leachate conductivity test were useful for comparison before PCT elemental release results were available. A glass formulation K11A meets all the KHNP glass property constraints, and use of this glass formulation on the pilot scale is recommended. Glass formulations K12A, K12B, and K12E meet nearly all of the processing constraints and may be suitable for additional testing. Based on the comparison between the measured and predicted glass properties, existing glass property models may be used to assist with the LILW glass formulation development.

Implant Anneal Process for Activating Ion Implanted Regions in SiC Epitaxial Layers

  • Saddow, S.E.;Kumer, V.;Isaacs-Smith, T.;Williams, J.;Hsieh, A.J.;Graves, M.;Wolan, J.T.
    • Transactions on Electrical and Electronic Materials
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    • 제1권4호
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    • pp.1-6
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    • 2000
  • The mechanical strength of silicon carbide dose nor permit the use of diffusion as a means to achieve selective doping as required by most electronic devices. While epitaxial layers may be doped during growth, ion implantation is needed to define such regions as drain and source wells, junction isolation regions, and so on. Ion activation without an annealing cap results in serious crystal damage as these activation processes must be carried out at temperatures on the order of 1600$^{\circ}C$. Ion implanted silicon carbide that is annealed in either a vacuum or argon environment usually results in a surface morphology that is highly irregular due to the out diffusion of Si atoms. We have developed and report a successful process of using silicon overpressure, provided by silane in a CAD reactor during the anneal, to prevent the destruction of the silicon carbide surface, This process has proved to be robust and has resulted in ion activation at a annealing temperature of 1600$^{\circ}C$ without degradation of the crystal surface as determined by AFM and RBS. In addition XPS was used to look at the surface and near surface chemical states for annealing temperatures of up to 1700$^{\circ}C$. The surface and near surface regions to approximately 6 nm in depth was observed to contain no free silicon or other impurities thus indicating that the process developed results in an atomically clean SiC surface and near surface region within the detection limits of the instrument(${\pm}$1 at %).

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골 생체조직공학을 위한 복합 세라믹 골 지지체의 제조와 생체역학적 특성 (Fabrication and Biomechanical Characteristics of Composite Ceramic Bone Scaffolds for Bone Tissue Engineering)

  • 김은석;정종훈
    • Journal of Biosystems Engineering
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    • 제29권5호
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    • pp.457-466
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    • 2004
  • Novel porous composite ceramic bone scaffolds composed of biodegradable PHBV(polyhydroxybutyrate-co-hydroxyvalerate) and TA(toothapatite) have been fabricated for bone tissue engineering by a modified solvent casting and particulate leach-ing method with salt-contained heat compression technique. The results of this study suggest that the PHBV-TA composite scaffold, especially the scaffold containing 30 weight$\%$ of TA may be a good candidate far bone tissue engineering of non-load bearing area in oral and maxillofacial region.

한국산 미기록과 애기버섯벌레과(딱정벌레목: 거저리상과)에 속한 Octotemnus Mellie 2 미기록종과 숙주버섯 (First Record of the Family Ciidae (Coleoptera: Tenebrionoidea), from Korea, with two Unrecorded Species of Octotemnus Mellie on Fungi)

  • 정부희
    • 한국응용곤충학회지
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    • 제49권2호
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    • pp.83-88
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    • 2010
  • 한국산 미기록과 애기버섯벌레과(Ciidae, Leach)(신칭)에 속한 Octotemnus Melli$\acute{e}$(딱정벌레목: 거저리상과)(신칭)의 분류학적 연구를 수행하였다. 이 속에 속한 Octotemnus laminifrons (Motschulsky)(턱애기버섯벌레)(신칭)와 Octotemnus japonicus Miyatake(일본턱애기버섯벌레)(신칭) 등 2종을 국내에서 처음으로 분류학적으로 검토하고 야외관찰과 실내사육을 통해 숙주버섯을 밝혔다. 각 종에 대한 검색키, 기재문, 진단형질 그림, 성충사진과 숙주버섯을 제공하였다.

A new record of Caprella aino (Crustacea: Amphipoda: Caprellidae) from the southeastern waters of Korea, with comparison to Caprella mutica

  • Gi Beom Ryu;Won Gyu Park
    • Fisheries and Aquatic Sciences
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    • 제26권7호
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    • pp.455-459
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    • 2023
  • 40 species of the family Caprellidae Leach, 1814 are recorded in Korean waters. Caprella aino Utinomi, 1943 was newly collected from seaweed farms from the southeastern waters of Korea. C. aino was firstly reported in Japanese waters in 1943. Adults of C. aino and Caprella mutica Schurin, 1935 are easily distinguished in that C. aino have pereonite II and gnathopod II without setae and two small tubercles of articulation of gills in pereonite III-IV, while C. mutica do pereonite II and gnathopod II covered with setae and those of pereonites III-VII with many tubercles. However, subadult C. mutica is hardly distinguishable from C. aino in that tubercles of pereonite III are less developed and they have inconspicuous setae of pereonite II and gnathopod II. Nevertheless, C. aino is distinguished from subadult C. mutica because adult C. aino have dorsal tubercles on pereonite IV, V, VI, VII unlike that of C. mutica. We report C. aino as a new record in Korean water with comparison of C. mutica.

Glass Dissolution Rates From MCC-1 and Flow-Through Tests

  • Jeong, Seung-Young
    • 한국방사성폐기물학회:학술대회논문집
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    • 한국방사성폐기물학회 2004년도 학술논문집
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    • pp.257-258
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    • 2004
  • The dose from radionuclides released from high-level radioactive waste (HLW) glasses as they corrode must be taken into account when assessing the performance of a disposal system. In the performance assessment (PA) calculations conducted for the proposed Yucca Mountain, Nevada, disposal system, the release of radionuclides is conservatively assumed to occur at the same rate the glass matrix dissolves. A simple model was developed to calculate the glass dissolution rate of HLW glasses in these PA calculations [1]. For the PA calculations that were conducted for Site Recommendation, it was necessary to identify ranges of parameter values that bounded the dissolution rates of the wide range of HLW glass compositions that will be disposed. The values and ranges of the model parameters for the pH and temperature dependencies were extracted from the results of SPFT, static leach tests, and Soxhlet tests available in the literature. Static leach tests were conducted with a range of glass compositions to measure values for the glass composition parameter. The glass dissolution rate depends on temperature, pH, and the compositions of the glass and solution, The dissolution rate is calculated using Eq. 1: $rate{\;}={\;}k_{o}10^{(ph){\eta})}{\cdot}e^{(-Ea/RT)}{\cdot}(1-Q/K){\;}+{\;}k_{long}$ where $k_{0},\;{\eta}$ and Eaare the parameters for glass composition, pH, $\eta$ and temperature dependence, respectively, and R is the gas constant. The term (1-Q/K) is the affinity term, where Q is the ion activity product of the solution and K is the pseudo-equilibrium constant for the glass. Values of the parameters $k_{0},\;{\eta}\;and\;E_{a}$ are the parameters for glass composition, pH, and temperature dependence, respectively, and R is the gas constant. The term (1-Q/C) is the affinity term, where Q is the ion activity product of the solution and K is the pseudo-equilibrium constant for the glass. Values of the parameters $k_0$, and Ea are determined under test conditions where the value of Q is maintained near zero, so that the value of the affinity term remains near 1. The dissolution rate under conditions in which the value of the affinity term is near 1 is referred to as the forward rate. This is the highest dissolution rate that can occur at a particular pH and temperature. The value of the parameter K is determined from experiments in which the value of the ion activity product approaches the value of K. This results in a decrease in the value of the affinity term and the dissolution rate. The highly dilute solutions required to measure the forward rate and extract values for $k_0$, $\eta$, and Ea can be maintained by conducting dynamic tests in which the test solution is removed from the reaction cell and replaced with fresh solution. In the single-pass flow-through (PFT) test method, this is done by continuously pumping the test solution through the reaction cell. Alternatively, static tests can be conducted with sufficient solution volume that the solution concentrations of dissolved glass components do not increase significantly during the test. Both the SPFT and static tests can ve conducted for a wide range of pH values and temperatures. Both static and SPFt tests have short-comings. the SPFT test requires analysis of several solutions (typically 6-10) at each of several flow rates to determine the glass dissolution rate at each pH and temperature. As will be shown, the rate measured in an SPFt test depends on the solution flow rate. The solutions in static tests will eventually become concentrated enough to affect the dissolution rate. In both the SPFt and static test methods. a compromise is required between the need to minimize the effects of dissolved components on the dissolution rate and the need to attain solution concentrations that are high enough to analyze. In the paper, we compare the results of static leach tests and SPFT tests conducted with simple 5-component glass to confirm the equivalence of SPFT tests and static tests conducted with pH buffer solutions. Tests were conducted over the range pH values that are most relevant for waste glass disssolution in a disposal system. The glass and temperature used in the tests were selected to allow direct comparison with SPFT tests conducted previously. The ability to measure parameter values with more than one test method and an understanding of how the rate measured in each test is affected by various test parameters provides added confidence to the measured values. The dissolution rate of a simple 5-component glass was measured at pH values of 6.2, 8.3, and 9.6 and $70^{\circ}C$ using static tests and single-pass flow-through (SPFT) tests. Similar rates were measured with the two methods. However, the measured rates are about 10X higher than the rates measured previously for a glass having the same composition using an SPFT test method. Differences are attributed to effects of the solution flow rate on the glass dissolution reate and how the specific surface area of crushed glass is estimated. This comparison indicates the need to standardize the SPFT test procedure.

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CCA 방부처리 목재로부터 크롬, 구리 및 비소의 용탈 특성 (Characteristics of Chromium, Copper, and Arsenic Leaching from CCA-Treated Wood)

  • 김희갑;김동진
    • Environmental Analysis Health and Toxicology
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    • 제22권4호
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    • pp.339-348
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    • 2007
  • A laboratory experiment was conducted to study the characteristics of leaching of Cr, Cu, and As from chromated topper arsenate (CCA)-treated wood. The wood species tested was hemlock spruce ($10\;cm\;{\times}\;10\;cm\;{\times}\;10\;cm\;tube$). The leaching experiment was conducted over 60 days using I L of leachants whose pHs were adjusted to 2.0, 3.7, and 1.6, respectively with nitric acid, and also using lake water, according to the OECD guideline. Each leachate was analyzed for Cr and Cu using flame-AAS, and for As using vapor generation-AAS. Three metals were loathed at the highest levels at pH 2.0 but almost at similar levels at the other conditions. Cumulative quantifies over 60 days of a leaching period were in order of As>Cu>Cr. As was predicted to leach with an increase in flux over a 10 year period, while Cr and Cu fluxes were predicted to decrease with time. This result suggest that arsenic can pose a health risk to humans over a long period of time, when CCA-treated wood is used for building facilities (e.g., playgrounds, residential purposes, etc.) with which humans frequently contact.

낙엽날개뱀잠자리붙이아과의 미기록속 및 미기록종, Drepanepteryx phalaenoides (Linné) (풀잠자리목:뱀잠자리붙이과) (A New Record of the Genus and Species, Drepanepteryx phalaenoides (Linné) (Neuroptera:Hemerobiidae:Drepanepteryginae) from Korea)

  • 김슬기;조수원
    • 한국응용곤충학회지
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    • 제55권3호
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    • pp.309-312
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    • 2016
  • 그 동안 국내 Drepanepteryginae 아과(낙엽날개뱀잠자리붙이아과; 신칭)에는 오직 Neuronema albostigma만이 기록되어 있었으나, 이번 연구를 통해 국내 미기록속인 Drepanepteryx와 이 속에 포함되는 미기록종 Drepanepteryx phalaenoides (낙엽날개뱀잠자리붙이; 신칭)를 새롭게 보고한다. 이 종에 대한 간략한 기재와 속내 분류키, COI 바코드 염기서열, 그리고 성충 및 수컷 생식기의 사진을 제공한다.

고온.산소가압하(高溫.酸素加壓下)에서의 황동광(黃銅鑛)의 황산침출 거동 고찰 (Behavior of the High Temperature Oxygen Pressure Leaching of Chalcopyrite in Sulfuric Acid Solution)

  • 엄형춘;윤호성;유경근;손정수
    • 자원리싸이클링
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    • 제16권3호
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    • pp.44-49
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    • 2007
  • 본 연구는 고온 산소가압 하에서의 황동광(칠레산 에스콘디다광석) 황산침출에 관한 연구로 침출시간, 침출온도, 산소압력에 따른 Cu 침출율 및 침출거동에 대하여 고찰하였다. 침출온도가 Cu의 침출율에 미치는 영향이 가장 켰으며, 산소압력은 큰 영향을 미치지 않았다. 침출온도 $200^{\circ}C$, 산소압력 10 atm인 조건으로 2시간 침출하여 87.1%의 Cu를 침출하였으며, 이 때 함께 침출된 Fe는 대부분 hematite($Fe_2O_3$) 형태로 재침전이 일어났다. 산소가압 하에 고온($150^{\circ}C$ 이상) 침출조건에서 황동광 침출반응은 주로 산소의 산화작용에 의한 분해인 것을 확인하였으며, 황은 대부분 황산염 형태로 산화되어 단체황 생성으로 인한 passivating 현상은 일어나지 않은 것으로 사료된다.