• 제목/요약/키워드: Stage 2

검색결과 20,174건 처리시간 0.052초

Li, K과 Na-흑연 층간화합물의 stage 전이특성 (Stage transformation characteristice of Li, K and Na-graphite intercalation compounds)

  • 오원춘;임창성;오근호;고영신
    • 한국결정성장학회지
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    • 제8권1호
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    • pp.83-90
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    • 1998
  • Li, K과 Na-흑연 층간화합물의 stage 전이 특성을 탄소층사이에 존재하는 intercalants의 deintercalation 메카니즘을 고려하여 제시하였다. 온도와 압력을 조절하여 합성된 Li-GICs(graphite intercalation compounds)를 분위기하에서 자발적으로 분해시켰다. 이들 화합물을 XRD 분석한 결과 1, 2 stage의 d001-값이 각각 3.71, 7.06 $\AA$으로 나타났다. 분위기하에서 Li-GiCs를 deintercalation 반응을 시킨 6주 후에 잔유화합물이 형성됨을 알 수 있었다. 또한, two-bulb 법으로 K-GICs를 합성하였으며, K-GDICs(graphite deintercalation compounds)의 구조적 안정성과 stage 전이에 대하여 조사하였다. X-선회절 결과로부터 K-GDICs는 10주 동안 안정한 K-흑연 잔유 화합물을 형성하였다. 그리고 고온, 고압법을 이용하여 합성된 1, 2stage의 Na-GICs의 deintercalation 반응과 열적 안정성에 대한 온도 의존성에 대하여 논하였다. 열적 안정성과 관련하여 Na-GICs의 구조변화를 XRD에 의하여 확인하였다. 이들 과정에 따르면 stage 전이는 무질서한 stage를 가진 GDICs의 불규칙적인 deintercalation에 의하여 형성됨을 제시할 수 있었다.

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한반도 후빙기의 저지대 식생사 (The Post-glacial Vegetation History of the Lowland in Korean Peninsula)

  • 최기룡
    • The Korean Journal of Ecology
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    • 제21권2호
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    • pp.169-174
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    • 1998
  • This is the review of vegetational history of the post-glacial period in Korea. most of studies for vegetational changes are located in the lowland alluvial plain, especially below the hilly zone of western and eastern coastal regions of Korea. A couple of methods, pollen analysis and radiocarbon dating, have been employed in these studies. These results lead us to establish the pollen zonation in Korea as the followings. Yasuda et al.(1980) classified six period in Yongrang lake of sokcho. These are as follow I. 17,000-15,000yr B.P.: Picea, Abies, Pinus(Haploxylon), Larix stage, II.15,000-10,000yr B.P:Herb, Pteridophyta stage, III.10.000-6,700yr BP.:Quercus stage, IV.6,700-4,500yr B.P.:Pinus, Quercus, Carpinus stage, V.4,500-1,400yr B.P.:Quercus. Pinus stage, VI.1,400yr B.P.-present: Pinus, Herbs stage. Jo(1979) also divided the period into two stages from the outcomes of analysis done in Jumoonjin and other sites I.10,000-6,000yr B.P.:Quercus stage, II.6,000-present: Pinus-Quercus stage, and three substages: IIa.6,000-3,400 yr B.P.:lower Pinus stage, IIb.3,400-2,000yr B.P.:Pinus-Quercus stage, IIc.2,000-present: Pinus stage. Choi(1993, 1996) divided the period into three stages: I.6,000-5,000yr B.P.:Alnus, Quercus stage, II.5,000-4,000yr B.P.: Alnus, Quercus, Pinus stage, III.4,500-2,600yr B.P.: Alnus, Pinus stage. In the period around 6,000yr B.P. distinct dominant species clearly occupied the lowland of the eastern and western coasts. Thus, this strongly supports the fact that even if Korea experienced its warm and wet climate after the lateglacial, it underwent a different environmental change, dry climate, compared to the regions of Japan.

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스캐닝 방식 XY 스테이지의 운동오차 분석 (The Analysis of Motion Error in Scanning Type XY Stage)

  • 황주호;박천홍;이찬홍;김동익;김승우
    • 한국정밀공학회:학술대회논문집
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    • 한국정밀공학회 2004년도 추계학술대회 논문집
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    • pp.1380-1383
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    • 2004
  • The scanning type XY stage is frequently used these days as precision positioning system in equipment for semiconductor or display element. It is requested higher velocity and more precise accuracy for higher productivity and measuring performance. The position accuracy of general stage is primarily affected by the geometric errors caused by parasitic motion of stage, misalignments such as perpendicular error, and thermal expansion of structure. In the case of scanning type stage, H type frame is usually used as base stage which is driven by two actuators such as linear motor. In the point view of scanning process, the stage is used in moving motion. Therefore, dynamic variation is added as significant position error source with other parasitic motion error. Because the scanning axis is driven by two actuators with two position detectors, 2 dimensional position errors have different characteristic compared to general tacked type XY stage. In this study 2D position error of scanning stage is analyzed by 1D heterodyne interferometer calibrator, which can measure 1D linear position error, straightness error, yaw error and pitch error, and perpendicular error. The 2D position error is evaluated by diagonal measurement (ISO230-6). The yaw error and perpendicular error are compensated on the base stage of scanning axis. And, the horizontal straightness error is compensated by cross axis compensation. And, dynamic motion error in scanning motion is analyzed.

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Two Stage 발효에 의한 고산도 식초 생산 (Production of High Acetic Acid Vinegar Using Two Stage Fermentation)

  • 이영철;이금용;김형찬;박기범;유익제;안평욱;최춘언;손세형
    • 한국미생물·생명공학회지
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    • 제20권6호
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    • pp.663-667
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    • 1992
  • 산업적으로 산도 17.0 이상의 고산도 시초를 생산하기 위하여 반연속식인 1st stage와 유가식인 2nd stage로 구성된 two stage 초산 발효를 온도 $30^{\circ}C$, 교반속도 600rpm, 통기량 0.1vvm에서 실시하였다. 1st stage에서 초기 에탄올 농도를 $50.0g/{\ell}$, 잔류 에탄올 농도를 $5.0g/{\ell}$로 정하여 반연속적으로 초산발효를 하고, 2nd stage에서 발효시간의 경과에 따라 에탄올을 유가식으로 첨가하여 초산발효액내의 에탄올 농도를 $5.0g/{\ell}$에서 $10.0g/{\ell}$로 유지했을 때 산도가 17.6인 고산도 식초를 생산 할 수 있었으며, 또한 이때의 최대 초산 생산성은 $3.3g/{\ell}{\cdot}hr$였다.

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고추냉이의 미숙배배양으로부터 체세포배 발생과 식물체 재분화 (Somatic Embryogenesis and Plant Regeneration from Immature Zygotic Embryo Culture of Wasabia japonica Matsum.)

  • 은종선;고정애;김영선;김명준
    • 식물조직배양학회지
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    • 제22권4호
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    • pp.207-211
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    • 1995
  • 고추냉이의 미숙배를 어뢰형 배(stage I )와 자엽배의 (stage II )로 구분하여 캘러스, 배발생 및 식물체 재분화에 미치는 생장조절제의 효과와 치상적기를 조사하였다. 캘러스 및 배발생은 미숙배의 자엽부분에서 관찰되었는데 캘러스의 양상에 따라 기관분화와 배발생이 이루어졌다. 캘러스 형성률은 stage I의 경우 1.0 mg/L IAA에서, stage II의 경우 1.0 mg/L 2,4-D와 0.1 mg/L BA 혼용처리구에서 가장 양호하였다. 체세포배 발생은 stage I의 미숙배는 생장조절제 무처리구에서, stage II의 미숙배는 1.0 mg/L IAA 처리구에서 가장 높았으며 캘러스를 통하거나 자엽에서 직접 발생되었다. Stage II의 미숙배가 stage I에 비해 캘러스 및 체세포배 발생이 왕성하였다. 이들 체세포배는 동일배지에서 계대배양하여 정상적인 식물체로 재생되었다.

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운전조건 변화에 따른 이산화탄소 냉방시스템들의 성능 비교 (Comparisons of Performance in CO2 Systems with Operating Conditions)

  • 배경진;신은성;조홍현
    • 대한설비공학회:학술대회논문집
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    • 대한설비공학회 2009년도 하계학술발표대회 논문집
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    • pp.1484-1490
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    • 2009
  • Since the cooling performance of a $CO_2$ cooling cycle is varied significantly with a variation of refrigerant charge amount and outdoor temperature, the reliability of $CO_2$ system is down. In this study, the performance characteristics of three kinds of $CO_2$ systems were measured and analyzed by varying refrigerant charge amount and outdoor temperature so as to study the characteristics of variation with cycle option. The applied system options are the single-stage compression(1C-1E) system, two-stage compression with 1-EEV(2C-1E) system, and two-stage compression with 2-EEV(2C-2E) system. The performances of two-stage compression with 2-EEV system were less sensitive than those of other systems and the system operated safely and steadily for wide charge amount. The performance of the two-stage compression with 1-EEV(2C-1E) system was the most sensitive to the charge amount, and that of the single-stage compression(1C-1E) system varied a lot with outdoor temperature.

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장군광산(將軍鑛山)의 자철석광상(磁鐵石鑛床)에서 산출(産出)되는 광석광물(鑛石鑛物)과 생성조건(生成條件) (Ore Minerals and Mineralization Conditions of Magnetite Deposits in the Janggun Mine, Korea)

  • 이현구;이찬희;송석환
    • 자원환경지질
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    • 제29권1호
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    • pp.1-11
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    • 1996
  • Magnetite ores of the Janggun mine are embedded in dolomitic limestone of the Janggun Limestone Formation contacting with Chunyang granite, and are closely associated with skarn minerals. Mineralization of magnetite deposits can be divided into two stages as deep-seated skarn stage and shallow hydrothermal replacement stage. Mineralogies of skarn stage consist of magnetite, pyrrhotite and base-metal sulfides, and those of hydrothermal stage is base-metal sulfides, native bismuth, bismuthinite, tetrahedrite, boulangerite, bournonite and stannite. The FeS mole % in sphalerite and As atom % in arsenopyrite range from 22.47 to 26.30 and from 31.39 to 31.66 in skarn stage, and are from 17.54 to 32.54 and 28.87 to 30.70 in hydrothermal stage, respectively. Based on mineralization characteristics, mineral assemblages, chemical compositions and thermodynamic considerations, formation temperatures, sulfur fugacities ($-logf_2$), pH and oxygen fugacity ($-logfo_2$) estimated to be from 345 to $382^{\circ}C$, from 8.1 to 9.7atm, from 6.5 to 7.2 and from 30.5 to 31.2atm in the skarn stage, respectively, and temperature and $-logfs_2$ are from 245 to $315^{\circ}C$ and from 10.4 to 13.2atm in the hydrothermal stage.

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Chlorella의 생활사를 통한 -SH화합물 함량의 변화 (The changes in the Amounts of SH Compounds in Chlorella during the Synchronous Culture)

  • 최호형;이영녹
    • 미생물학회지
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    • 제19권1호
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    • pp.8-13
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    • 1981
  • The content of sulfhydryl compounds in Chlorella cells during the life cycle in the synchronous culture is determined spectrophotomatically at 250nm(pH7.0) using p-CMB as SH-reagent. The changes in the content of-SHl compounds and protein in Chlorella cells is measured during the life cycle in connection with cell division and analyzed. 1) The amounts of total ninhydrin reactive substance increased with growth of cells but increased the more at the $L_4$ stage(cytokinesis stage) than at the $L_2$ stage (nuclear division stage). 2) The sulfhydryl content of Chlorella cells increased strikingly at the $L_2$ stage and decreased markedly at the $L_4$ stage. 3) The amounts of values -SH/protein showed a peak at the $L_2$ stage. The increase of the amount of total-SH compounds of cells during the nuclear division period was considered to be caused by the weighty roles of protein-SH groups for the formation of nuclear division apparatus and for the enzyme activity.

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친환경 프레온 냉매를 이용하는 단압축 단팽창 냉동시스템의 성능예측 (Performance Analysis of Two-stage Compression and Two-stage Expansion Refrigeration System using Freon Refrigerants)

  • 노건상;김종열
    • 수산해양교육연구
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    • 제25권2호
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    • pp.301-306
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    • 2013
  • In this paper, cycle performance analysis of two-stage compression and two-stage expansion refrigeration system using alternative freon refrigerants is presented to offer the basic design data for the operating parameters of the system. Alternative freon refrigerant for freon refrigerant R22 were used as working fluids in this study. The operating parameters considered in this study included evaporation temperature, condensation temperature, subcooling degree, superheating degree, and mass flow rate ratio of inter-cooler. The main results were summarized as follows : The COP of two-stage compression and two-stage expansion refrigeration system increases with the increasing subcooling degree and mass flow rate ratio of inter-cooler, but decreases with the increasing evaporating temperature, condensing temperature and superheating degree. Therefore, subcooling degree, mass flow rate ratio of inter-cooler of two-stage compression and two-stage expansion refrigeration system using alternative freon refrigerants have an effect on COP of this system.

여과 성능향상을 위한 이단이층 복합여과시스템의 공정선정 연구 (A Study on the Process Selection for Two-stage and Dual Media Filtration System for Improving Filtration Performance)

  • 송시범;조민;남상호;우달식
    • 상하수도학회지
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    • 제21권2호
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    • pp.203-214
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    • 2007
  • This study aimed at researching the process selection for two-stage and dual media filtration system, as a technology substituting the existing sand filter without expanding the site when retrofitting an old filter bed or designing a new one. In order to select the process for optimum complex filtration system, three running conditions have been tested. Test results demonstrated that Run 3 in which the 1st stage was filled with anthracite and coarse sand, and the 2nd stage was filled up with activated carbon and fine sand reduced the head loss and the load of turbidity substances. Also, Run 3 showed better performance in removing TOC, particle counts, THMFP and HAAFP, compared to other two conditions. 99 % of Cryptosporidium was removed. Bisphenol-A was rarely removed from the 1st stage of coarse sand and 2nd stage of fine sand, but 99 % of it was removed from the 2nd stage of activated carbon. In conclusion, when it is required to retrofit an old rapid filter bed or design a new one for the purpose of improving filtration performance, the following two-stage and dual media filtration system is suggested: the 1st stage of filter bed needs to be filled up with coarse sand to remove turbidity as the pretreatment for extending duration of filtering, the top part of 2nd stage needs to be filled up with granular activated caron to remove dissolved organic matters and others as the main process, and finally the bottom part of 2nd stage needs to be filled up with fine sand as the finishing process.