• 제목/요약/키워드: W/Mo

검색결과 759건 처리시간 0.023초

HANARO Fission Moly Target으로서의 LEU와 HEU의 특성 비교

  • 조동건;김명현
    • 한국원자력학회:학술대회논문집
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    • 한국원자력학회 1997년도 춘계학술발표회논문집(1)
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    • pp.108-113
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    • 1997
  • 하나로(HANARO)를 이용하여 핵분열 방법으로 진단용 방사선원인 $^{99m}$ Tc의 모핵종인 Mo-99를 생산할 경우, HEU 및 LEU UO2 표적이 사용될 수 있다. 표적연료로서 HEU(93w/o $^{235}$ U)가 LEU(19.75w/o $^{235}$ U)에 비해 생성수율(Ci/gU)이 높게 나타났으며 제품의 질(quality)을 좌우하는 비방사능(Ci$^{99}$Mo/gMo)은 같게 나타났다. HEU가 같은 Mo-99의 방사능량을 얻기 위해서는 우라늄 장전량이 적어지므로 폐기물측면과 용해측면에서 이득이나 농축도를 고려하면, 큰 이득이 발생하지 않으므로 하나로에 LEU를 사용하는 것도 타당하다 할 수 있다.

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Effect of Monensin and Fish Oil Supplementation on Biohydrogenation and CLA Production by Rumen Bacteria In vitro When Incubated with Safflower Oil

  • Wang, J.H.;Choi, S.H.;Yan, C.G.;Song, M.K.
    • Asian-Australasian Journal of Animal Sciences
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    • 제18권2호
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    • pp.221-225
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    • 2005
  • An in vitro study was conducted to examine the effect of monensin or fish oil addition on bio-hydrogenation of $C_{18^-} unsaturated fatty acids and CLA production by mixed ruminal bacteria when incubated with safflower oil. Commercially manufactured concentrate (1%, w/v) with safflower oil (0.2%, w/v) were added to mixed solution (600 ml) of strained rumen fluid and McDougalls artificial saliva (control). Monensin $Rumensin^{(R)}$, 10 ppm, w/v, MO), mixed fish oil (0.02%, w/v, absorbed to 0.2 g alfalfa hay, FO) or similar amounts of monensin and fish oil (MO+FO) to MO and FO was also added into the control solution. All the culture solutions prepared were incubated in the culture jar anaerobically at $39^{\circ}C$ up to 12 h. Higher pH (p<0.047) and ammonia concentration (p<0.042) were observed from the culture solution containing MO at 12 h incubation than those from the culture solutions of control or FO. The MO supplementation increased (p<0.0001-0.007) propionate proportion of culture solution but reduced butyrate proportion at 6 h (p<0.018) and 12 h (p<0.001) of incubations. Supplementation of MO or MO+FO increased (p<0.001) the proportions of $C_{18:2}$. The MO alone reduced (p<0.022-0.025) the proportion of c9,t11-CLA compared to FO in all incubation times. The FO supplementation increased the proportion of c9,t11-CLA. An additive effect of MO to FO in the production of c9,t11-CLA was observed at 6 h incubation. In vitro supplementation of monensin reduced hydrogenation of $C_{18^-}$UFAs while fish oil supplementation increased the production of CLA.

Tape Casting법을 이용한 W-Cu, Mo-Cu 박판소재 제조 (Manufacturing of W-Cu and Mo-Cu Sheet by Tape Casting Method)

  • 박치완;장건익;김태형;우용원
    • 열처리공학회지
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    • 제17권5호
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    • pp.293-298
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    • 2004
  • For the application of heat sink device, the green sheets of powder of W-XCu and Mo-XCu composites were fabricated by tape casting technique. The mixing ratio of powder and binder was 6:4. The green sheet was shrinked up to 10~20% after sintering and the maximum relative density was above 95%. Thermal conductivity and Thermal expansion systematically increased with increasing Cu contents. The maximum thermal conductivity of W-20wt.%Cu was about 206[W/mK].

25Cr-7Ni-2Mo-4W 슈퍼 2상 스테인리스강의 충격인성에 미치는 χ상의 영향 (Effect of χ Phase on Impact Toughness of 25Cr-7Ni-2Mo-4W Super Duplex Stainless Steel)

  • 남궁원;강창룡
    • 한국해양공학회지
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    • 제27권2호
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    • pp.75-79
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    • 2013
  • This study was carried out to investigate the precipitation behavior of the ${\chi}$ phase and the impact toughness of 25%Cr-7%Ni-2%Mo-4%W super duplex stainless steel. The ${\chi}$ phase was precipitated in the early stage of aging, and with the increasing aging time. However, after reaching a maximum value, the number decreased as a result of the gradual transformation of the ${\chi}$ phase into the ${\sigma}$-phase. It was proved that the ${\chi}$ phase was an intermetallic compound, which represented a lower nickel concentration, higher chromium and molybdenum concentrations, and very higher tungsten concentration compared to the matrix phases. It also showed higher molybdenum and tungsten concentrations than the ${\sigma}$ phase. The decomposition of the ferrite phase into the ${\gamma}_2$ and ${\sigma}$ phases was retarded by W substitution for Mo. Thus, the number of ${\chi}$ phases increased. The impact value was decreased by the substitution of W for Mo. The impact toughness rapidly decreased with time when the ${\chi}$ phase began to precipitate in the initial stage of aging. The impact toughness was, therefore, greatly influenced for the precipitation of the ${\chi}$ phase.

Fe-3%C-x%Cr-y%V-w%Mo-z%W 다합금계백주철의 주방상태 및 급냉조직 (As-Cast and Solidification Structures of Fe-3%C-x%Cr-y%V-w%Mo-z%W Multi- Component White Cast Irons)

  • Yu, sung-Kon;Shin, Sang-Woo
    • 한국재료학회지
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    • 제12권5호
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    • pp.414-422
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    • 2002
  • Three different multi-component white cast irons alloyed with Cr, V, Mo and W were prepared in order to study their as-cast and solidification structures. Three combinations of the alloying elements were selected so as to obtain the different types of carbides and matrix structures : 3%C-10%Cr-5%Mo-5%W(alloy No.1), 3%C-10%V-5% Mo-5%W(alloy No. 2) and 3%C-17%Cr-3% V(alloy No.3). The as-cast microstructures were investigated with optical and scanning electron microscopes. There existed two different types of carbides, $M_7C_3$ carbide with rod-like morphology and $M_6C$ carbide with fishbone-like one, and matrix in the alloy No. 1. The alloy No. 2 consisted of MC carbide with chunky and flaky type and needle-like $M_2C$ carbide, and matrix. The chunky type referred to primary MC carbide and the flaky one to eutectic MC carbide. The morphology of the alloy No. 3 represented a typical hypo-eutectic high chromium white cast iron composed of rod-like $M_7C_3$ carbide which is very sensitive to heat flow direction and matrix. To clarify the solidification sequence, each iron(50g) was remelted at 1723K in an alumina crucible using a silicon carbide resistance furnace under argon atmosphere. The molten iron was cooled at the rate of 10K/min and quenched into water at several temperatures during thermal analysis. The solidification structures of the specimen were found to consist of austenite dendrite(${\gamma}$), $ ({\gamma}+ M_7C_3)$ eutectic and $({\gamma}+ M_6C)$ eutectic in the alloy No. 1, proeutectic MC, austenite dendrite(${\gamma}$), (${\gamma}$+MC) eutectic and $({\gamma}+ M_2C)$ eutectic in the alloy No. 2, and proeutectic $M_7C_3$ and $ ({\gamma}+ M_7C_3)$ eutectic in the alloy No 3. respectively.

Synthesis, Characterization, and Catalytic Properties of Gp 6 Metal Complexes of 1-N,N-dimethylaminomethyl-$1^{\prime}$,2-bis(diphenylphosphino)ferrocene (FcNPP). X-ray Crystal Structure of W$(CO)_4({\eta}^2-FcNPP(O)-P,N)$

  • Kim, Tae-Jeong;Kim, Yong-Hoon;Kim, Eun-Jin;Oh, Sang-Ho;Kim, Hong-Seok;Jeong, Jong-Hwa
    • Bulletin of the Korean Chemical Society
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    • 제15권5호
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    • pp.379-386
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    • 1994
  • Reactions of 1',2-bis(diphenylphosphino)-l-(N,N-dimethylaminomethyl)ferrocene (FcNPP) with $M(CO)_6$ (M=Cr, Mo, W) in the presence of TMNO (Trimethylamine oxide) in a stoichiometric ratio of 1 : 1.5 : 3.5 produced a series of Gp 6 metal carbonyl derivatives with a variety of coordination modes: M(CO)$_4({\eta}^2$-FcNPP-P,P) (M=Cr, Mo, W), $M(CO)_5({\eta}^1-FcNPP-P) (M=Mo, W)\;,\; M_2(CO)_9({\eta}^1\;,\;{\eta}^2-FcNPP-P,P,N) (M=Cr, Mo)\;,\;M_2(CO)_{10}({\eta}^1\;,\;{\eta}^1-FcNPP-P,P) (M=Cr, Mo, W)\;, and\;W(CO)_4({\eta}^2-FcNPP(O)-P,N)$. All these complexes were characterized by microanalytical and spectroscopic techniques. In one case, the structure of W(CO)$_4({\eta}^2$-FcNPP(O)-P,N) was determined by X-ray crystallography. Crystals are monocinic, space group P$2_{1/C}$, with a=10.147(2), b=19.902(3), c=19.821(4) ${\AA},\;{\beta}=96.88(2)^{\circ},\;V=3974(l){\AA}^3$, Z=4, and $D_{calc}=1.64 g cm^{-3}$. The geometry around the central tungsten metal is a distorted octahedron, with the nitrogen and phosphorus atoms being cis to each other. Some of these complexes exhibited catalytic activities in the allylic oxidation and epoxidation of cholesterly acetate. Other oxidation products were also formed with the different chemical yields and product distribution depending upon the ligand and the central metal.

박막형 CIGS 연성태양전지용 Mo 배면전극 증착에 관한 연구

  • 김강삼;조용기
    • 한국진공학회:학술대회논문집
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    • 한국진공학회 2009년도 제38회 동계학술대회 초록집
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    • pp.169-169
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    • 2010
  • 박막형 CIGS 태양전지의 배면전극으로 사용되는 Mo 박막은 낮은 저항으로 인한 전기전도성과 열적 안전성이 아주 우수하다. 연구에서는 연성 CIGS 태양전지의 제조를 위한 Mo 배면전극의 대면적 증착기술에 관한 것으로 DC Magnetron Sputtering 공정을 이용하여 전주기술을 통한 Ni-Fe계 연성기판재 위에 졸걸법으로 합성된 $SiO_2$ 절연박막에 Mo 박막을 증착하는 것을 목적으로 하고 있다. 실험에서는 연성기판재 대신 시편을 Sodalime glass, Si wafer, SUS계 소재를 사용하여 스퍼터링 공정에 의한 Mo 박막을 증착하였다. 실험에서 타겟에 인가되는 전력과 공정압력을 변수로 하여 Mo 박막의 증착율, 전기저항성을 측정하였다. 타겟의 크기는 $80mm{\times}350mm$, 타겟과 기판간 거리 20cm 이었으며, 공정 압력은 2~50 mtorr 영역에서 인가전력을 0.5-1.5kW로 하였다. Mo 박막의 증착율과 전기적 특성을 측정하기 위하여 $\alpha$-step과 4-point probe(CMT-SR 1000N)를 이용하였다. 그리고 Mo 박막의 잔류응력을 측정하기 위하여 잔류응력측정기를 이용하였다. Mo 박막의 미세구조분석을 위하여 SEM 및 XRD를 분석을 실시하였다. 배면전극으로서 전기저항성은 공정압력에 따라 좌우 되었으며, 2 mTorr 공정압력과 1.5kW의 전력에서 최소값인 $8.2\;{\mu}{\Omega}-cm$의 저항값과 증착율 약 $6\;{\mu}/h$를 보였다. 기판재와의 밀착성과 관련한 잔류응력 측정과 XRD분석을 통한 결정립 크기를 분석하여 공정압력에 따른 Mo 박막의 잔류응력과 전기 저항 및 결정립 크기의 상관관계를 조사하였다. 그리고 대면적 CIGS 증착공정을 위해 직각형 타겟을 통해 증착된 Mo 박막의 증착분포를 20cm 이내 조사하였다.

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Reactions of Oxomolybdenum (Ⅴ) with the 17-tungsto-2-phosphate Anion

  • Lee, Chul-Wee;So, Hyun-Soo
    • Bulletin of the Korean Chemical Society
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    • 제5권4호
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    • pp.149-153
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    • 1984
  • Reactions of $MoOCl_5^{2-}$ with ${\alpha}_2-[P_2W_{17}O_{61}]^{10-}$ have been studied spectrophotometrically and several complexes have been identified. The transient species initially formed is probably $[Mo_2O_4(P_2W_{17}O_{6l})_2]^{18-}$. At $pH {\le} 3$the visible spectrum changes gradually, indicating formation of a transient isomer of $[P-2Mo^VW_{17}O_{62}]^{7-}$, which again transforms into the stable isomer. The transient isomer absorbs light much more strongly than the stable isomer in the visible range. At $pH > 3 [P_2W^VW_{16}O_{61}]^{11-}$ is formed probably via the transient isomer of $[P_2Mo^VW_{17}O_{61}]^{7-}$.

이온 빔 스퍼터링 방법으로 제작한 Mo 박막의 특성조사

  • 조상현;김효진;윤영목;이성호
    • 한국진공학회:학술대회논문집
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    • 한국진공학회 2012년도 제42회 동계 정기 학술대회 초록집
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    • pp.304-304
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    • 2012
  • CIGS(CuInGaSe2) 태양전지의 후면전극(Back contact)으로 널리 사용되는 Mo 박막은 낮은 면저항, 높은 반사율, 광흡수층 Na-path 제공 등의 조건이 요구된다. 일반적으로 Mo 박막 제작은 DC 마그네트론 스퍼터링 방법이 가장 널리 사용되며, 제작조건에 따라 태양전지 효율에 강한 영향을 미치는 것으로 보고되고 있다. 본 연구에서는 DC 마그네트론 스퍼터링 시 기판에 이온빔(Ion-beam)을 동시 조사하는 이온 빔 스퍼터링 증착(Ion-beam sputter deposition)법으로 Mo 박막을 제작하였다. 제작된 박막의 전기적 및 광학적 특성은 4-point probe, UV-Vis-NIR spectrometer로 각각 조사하였으며 Na-path 제어를 위한 구조적 특성은 XRD, FE-SEM으로 분석하였다. 분석결과에 따르면 기존 DC 마그네트론 스퍼터링 방법보다 상대적으로 더 치밀한 구조와 높은 반사율을 가지는 박막이 제작됨을 알 수 있었다. Mo 박막의 최적조건은 DC power 300 W, Ion-gun power 50 W, Ar flow rate 20 sccm 였다.

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