• 제목/요약/키워드: ThO_{2}$

검색결과 972건 처리시간 0.03초

산란계에 있어서 계분의 배설량과 이화학적 특성에 관한 연구 (Research on Quantity and Characteristics of Excreta Produced by Laying Hen)

  • 최희철;이덕수;강희설;곽정훈;최동윤;한정대;김형호
    • 한국축산시설환경학회지
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    • 제7권1호
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    • pp.39-44
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    • 2001
  • 산란계의 분 배설량과 그 특성을 알아보고자 축산기술연구소 환경조절축사에서 산란계 초생추 45수, 19주령과 55주령 산란계 48수를 이용하여 시험을 수행하였으며 그 결과는 다음과 같다. 1. 산란계 육성기 12주령시 배분량은 95.1g이었으며 수분함량은 77.5%였다, 도한 산란기 1일 사료섭취량은 105.1~122.9g이었고 음수량은 193.1~222.5$m\ell$였으며 분 배설량은 143.3~144.8g이었고 계분의 수분 함량은 74.7~80.5%였다. . 계분 중의 N 함량은 4.49~5.52%, ;$P_2O_5$는 육성기 1.22, 산란기 2.19~2.34%였으며 TEX>$K_2O$;는 1.23~3.52%였다. CaO는 육성기에 1.36%로 낮았으나 산란기에는 7.42~9.02%로 높았다. 3. 산란계 계분의 수질오염물질 농도는 $BOD_5$ 30.122, $COD_{MN}$$\ell$였으며, 중금속농도는 Cu 2~5mg/$\ell$, Pb 5.43~6.23mg/$\ell$으로 낮았다. 4. 무창계사의 여름철 계분의 수분함량은 65.4%로 자연환기 개방계사 계분 81.3%보다 낮았다.

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홀스타인 초유 whey fraction의 면역세포 활성화에 관한 연구 (Studies on the Immune Cell Activations of Bovine Colostral Whey Fractions)

  • 양희진;이승환;황보식;양동훈;이수원
    • 한국식품과학회지
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    • 제34권4호
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    • pp.694-699
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    • 2002
  • 본 연구에서는 분만 후 5일 이내에 분비되는 젖소 초유의 whey 및 whey 분획이 Th1 cell의 증식에 어떤 영향을 미치는지, 그리고 Th1 cell 증식에 직접적으로 관여하는 whey 분획이 macrophage의 $TNF-{\alpha}$ 분비에 미치는 영향을 조사하였다. 초유 whey를 ultrafiltration으로 분자량별로 분획한 결과, 단백질 성분의 회수율은 Fr. I, II, III가 각각 72%, 17.7%, 10.2%였으며, 당 성분의 회수율은 Fr. I, II, III가 각각 22.1%, 7.4%, 70.1%였다. Fr. II를 재분획한 Fr. P의 단백질 회수율과 Fr. O의 당 회수율은 각각 86.9%, 88.8%였다. 각각의 whey 분획의 농도 대비 Th1 cell 증식 효과를 검증한 결과, 1 mg/mL 농도에서 Fr. II가 Th1 cell을 가장 많이 자극시켰으며, 세포증식율은 67.1%였으나, Fr. II의 단백질 및 올리고당 분획의 세포증식효과는 없는 것으로 나타났다. Whey의 각각의 분획을 이용하여 $TNF-{\alpha}$ 분비 능력을 조사한 결과, Fr. O가 양성대조구로 사용한 LPS보다 약 80% 이상의 $TNF-{\alpha}$분비 유도 능력이 있는 것으로 나타났다.

Li 치환된 $Li[Li_yMn_{2-y}]O_4$ 정극 활물질의 결정 구조와 충방전 용량과의 관계 (The relation of the crystal phase and the charge/discharge capacity of $Li[Li_yMn_{2-y}]O_4$ cathode materials substituted Li)

  • 정인성;구할본;박복기;손명모;이헌수
    • 한국전기전자재료학회:학술대회논문집
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    • 한국전기전자재료학회 2000년도 춘계학술대회 논문집 전자세라믹스 센서 및 박막재료 반도체재료 일렉트렛트 및 응용기술
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    • pp.117-120
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    • 2000
  • The relation of crystal phase and charge/discharge capacity of $Li[Li_yMn_{2-y}]O_4$ were studied for different degrees of Li substitution (y). All cathode material showed spinel phase based on cubic phase in X-ray diffraction. Other peaks didn't show in spite of the increase of y value in $Li[Li_yMn_{2-y}]O_4$. Ununiform of $Li[Li_yMn_{2-y}]O_4$ which calcinated by (111) face and (222) face was more stable than that of pure $LiMn_2O_4$. In addition, At TG analysis, calcined $Li[Li_{0.1}Mn_{1.9}]O_4$ exhibited much mass loss at $800{\mu}m$. The cycle performance of the $Li(Li_yMn_{2-y}]O_4$ was improved by the substitution of $Li^{1+}$ for $Mn^{3+}$ in the octahedral sites. Specially, $Li[Li_{0.08}Mn_{1.92}]O_4$ and $Li[Li_{0.1}Mn_{1.9}]O_4$ cathode materials showed the charge and discharge capacity of about 125mAh/g at first cycle, and about 95mAh/g after 70th cycle. It is excellent than that of pure $LiMn_2O_4$, which 125mAh/g at first cycle, 65mAh/g at 70th.

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SiO2 완충층 두께에 따른 비정질 InGaZnO Pseudo-MOS Field Effect Transistor의 신뢰성 평가 (Effect of SiO2 Buffer Layer Thickness on the Device Reliability of the Amorphous InGaZnO Pseudo-MOS Field Effect Transistor)

  • 이세원;황영현;조원주
    • 한국전기전자재료학회논문지
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    • 제25권1호
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    • pp.24-28
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    • 2012
  • In this study, we fabricated an amorphous InGaZnO pseudo-MOS transistor (a-IGZO ${\Psi}$-MOSFET) with a stacked $Si_3N_4/SiO_2$ (NO) gate dielectric and evaluated reliability of the devices with various thicknesses of a $SiO_2$ buffer layer. The roles of a $SiO_2$ buffer layer are improving the interface states and preventing degradation caused by the injection of photo-created holes because of a small valance band offset of amorphous IGZO and $Si_3N_4$. Meanwhile, excellent electrical properties were obtained for a device with 10-nm-thick $SiO_2$ buffer layer of a NO stacked dielectric. The threshold voltage shift of a device, however, was drastically increased because of its thin $SiO_2$ buffer layer which highlighted bias and light-induced hole trapping into the $Si_3N_4$ layer. As a results, the pseudo-MOS transistor with a 20-nm-thick $SiO_2$ buffer layer exhibited improved electrical characteristics and device reliability; field effective mobility(${\mu}_{FE}$) of 12.3 $cm^2/V{\cdot}s$, subthreshold slope (SS) of 148 mV/dec, trap density ($N_t$) of $4.52{\times}1011\;cm^{-2}$, negative bias illumination stress (NBIS) ${\Delta}V_{th}$ of 1.23 V, and negative bias temperature illumination stress (NBTIS) ${\Delta}V_{th}$ of 2.06 V.

황해상공에서의 항공기관측에 의한 황화합물 장거리이동 특징에 대한 조사 (A Survey on the Long-range Transport of Sulfur Compounds by Aircraft Measurement over the Yellow Sea in 1998)

  • 김병곤;안준영;김종호;박철진;한진석;나진균;최양일
    • 한국대기환경학회지
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    • 제15권6호
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    • pp.713-725
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    • 1999
  • Air pollutants($SO_2$, NOx, $O_3$ and aerosol number) were measured using an aircraft to investigate the characteristical features of long-range transport of sulfur compounds over the Yellow Sea for the periods of 26~27 April and 7~10 November in 1998. The mean $SO_2$ concentrations of April 26th~27th and November 7th~10th flight were 0.6~1.8 ppb and 0.5~8.3 ppb, respectively, and the sulfur transport was largely limited to the atmospheric boundary layer. Especially, $SO_2$ increased up to 8.3 ppb altogether with the increase of particle number concentraton especially on November 8, 1998. In addition, $O_3$ was remarkably decreased against the increase of $SO_2$and particle number concentrations. This enhanced $SO_2$ concentration occurred in the low level westerlies in association with the anticyclonic flow over Southern China and the cyclonic circulation over Manchuria. Aerosol analyses at Taean site also showed that sulfate concentration increased 2~3 times higher than those of another sampling days, which could suggest possible interactions between aerosol particels and tropospheric ozone. A rigorous evaluation will be possible after the more intensive measurements and quantitative analyses with detailed chemistry model including the postulated heterogeneous mechanism.

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충남탄전, 대동누층군의 셰일과 탄질암에 관한 암석화학 및 환경지구화학적 특성 (Petrochemistry and Environmental Geochemistry of Shale and Coal from the Daedong Supergroup, Chungnam Coal Field, Korea)

  • 이찬희;이현구;김경웅
    • 자원환경지질
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    • 제30권5호
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    • pp.417-431
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    • 1997
  • Characteristics of sedimentary rocks and enrichment of toxic elements in shale and coal from the Chungnam coal field were investigated based upon geochemistry of major, trace and rare earth elements. Shale and coal of the area are interbedded along the Traissic to the Jurassic Daedong Supergroup, which can be subdivided into grey shale, black shale and coal. The coal had been mined, however all the mines are abandonded due to the economic problems. The shale and coal are characterized by relatively low contents of $SiO_2$, and $Al_2O_3$ and high levels of loss-on-ignition (LOI), CaO and $Na_2O$ in comparison with the North American Shale Composite (NASC). Light rare earth elements (La, Ce, Yb and Lu) are highly enriched with the coal. Ratios of $Al_2O_3/Na_2O$ and $K_2O/Na_2O$ in shale and coal range from 30.0 to 351.8 and from 4.2 to 106.8, which have partly negative correlations against $SiO_2/Al_2O_3$ (1.24 to 6.06), respectively. Those are suggested that controls of mineral compositions in shale and coal can be due to substitution and migration of those elements by diagenesis and metamorphism. Shale and coal of the area may be deposited in terrestrial basin deduced from high C/S (39 to 895) and variable composition of organic carbon (0.39 to 18.40 wt.%) and low contents of reduced sulfur (0.01 to 0.05 wt.%). These shale and coal were originated from the high grade metamorphic and/or igneous rocks, and the rare earth elements of those rocks are slightly influenced with diagenesis and metamorphism on the basis of $Al_2O_3$ versus La, La against Ce, Zr versus Yb, the ratios of La/Ce (0.38 to 0.85) and Th/U (3.6 to 14.6). Characteristics of trace and rare earth elements as Co/Th (0.07 to 0.86), La/Sc (0.31 to 11.05), Se/Th (0.28 to 1.06), V/Ni (1.14 to 3.97), Cr/V (1.4 to 28.3), Ni/Co (2.12 to 8.00) and Zr/Hf (22.6~45.1) in the shale and coal argue for inefficient mixing of the simple source lithologies during sedimentation. These rocks also show much variation in $La_N/Yb_N$ (1.36 to 21.68), Th/Yb (3.5 to 20.0) and La/Th (0.31 to 7.89), and their origin is explained by derivation from a mixture of mainly acidic igneous and metamorphic rocks. Average concentrations in the shale and coal are As=7.2 and 7.5, Ba=913 and 974, Cr=500 and 145, Cu=20 and 26, Ni=38 and 35, Pb=30 and 36, and Zn=77 and 92 ppm, respectively, which are similar to those in the NASC. Average enrichment indices for major elements in the shale (0.79) and coal (0.77) are lower than those in the NASC. In addition, average enrichment index for rare earth elements in coal (2.39) is enriched rather than the shale (1.55). On the basis of the NASC, concentrations of minor and/or environmental toxic elements in the shale and coal were depleted of all the elements examined, excepting Cr, Pb, Rb and Th. Average enrichment indices of trace and/or potentially toxic elements (As, Cr, Cu, Ni, Pb, U and Zn) are 1.23 to 1.24 for shale and 1.06 to 1.22 for coal, respectively.

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고용량 양극재료 개발을 위한 $LiNi_{1-y-z}(M_1)_y(M_2)_zO_2$의 합성과 전기화학적 특성 (Synthesis and Electrochemical Properties of $LiNi_{1-y-z}(M_1)_y(M_2)_zO_2$ for the Development of Cathode Materials with Large Capacity)

  • 송명엽
    • 한국수소및신에너지학회논문집
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    • 제18권3호
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    • pp.325-333
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    • 2007
  • [ $LiNi_{0.995}Al_{0.005}O_2$ ], $LiNi_{0.990}Ti_{0.010}O_2$ and $LiNi_{0.0990}Al_{0.005}Ti_{0.005}O_2$ were synthesized with a combustion method by calcining in an $O_2$ stream at $750^{\circ}C$ for 36 h. The X-ray diffraction patterns of these synthesized samples showed $-NaFeO_2$ structure of rhombohedral system(space group; $R{\bar{3}}\;m$) with no evidence of impurities. Among these samples, $LiNi_{0.995}Al_{0.005}O_2$ exhibited comparatively high first discharge capacity and discharge capacity, and the best cycling performance. $LiNi_{0.995}Al_{0.005}O_2$ had the first discharge capacity of 165.2 mA h/g and a discharge capacity of 116.7 mA h/g at the 50th cycle at 0.1C rate. It showed the first discharge capacity of 141.0 mA h/g and a discharge capacity of 93.5 mA h/g at the 50th cycle at 0.5C rate.

3D NAND Flash Memory의 Remnant Polarization(Pr)과 Saturated Polarization(Ps)에 따른 Retention 특성 분석 (The Analysis of Retention Characteristic according to Remnant Polarization(Pr) and Saturated Polarization(Ps) in 3D NAND Flash Memory)

  • 이재우;강명곤
    • 전기전자학회논문지
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    • 제26권2호
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    • pp.329-332
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    • 2022
  • 본 논문에서는 ferroelectric(HfO2)구조가 적용된 3D NAND flash memory의 parameter에 따른 lateral charge migration의 retention과 Vth를 분석하였다. Ps가 클수록 Program 시 ferroelectric에서 가능한 최대 polarization이 크기 때문에 초기 Vth는 Ps 25µC/cm2 보다 Ps 70µC/cm2에서 약 1.04V차이로 커진다. 또한 Program 이후 trap된 전자는 시간이 지남에 따라서 lateral charge migration이 발생한다. Program 이후 gate에 전압을 가하지 않고 ferroelectric은 polarization을 유지하기 때문에 Ps와 크게 관계없이 Pr이 클수록 polarization이 커지고 lateral charge migration에 의한 ∆Vth는 Pr 5µC/cm2 보다 Pr 50µC/cm2에서 약 1.54V차이로 작아진다.

Al2O3 층을 이용한 저온공정에서의 산화물 기반 트랜지스터 컨택 특성 향상 (Improved Contact property in low temperature process via Ultrathin Al2O3 layer)

  • 정성현;신대영;조형균
    • 한국표면공학회:학술대회논문집
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    • 한국표면공학회 2018년도 춘계학술대회 논문집
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    • pp.55-55
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    • 2018
  • Recently, amorphous oxides such as InGaZnO (IGZO) and InZnO (IZO) as a channel layer of an oxide TFT have been attracted by advantages such as high mobility, good uniformity, and high transparency. In order to apply such an amorphous oxide TFTs to a display, the stability in various environments must be ensured. In the InGaZnO which has been studied in the past, Ga elements act as a suppressor of oxygen vacancy and result in a decreased mobility at the same time. Previous studies have been showed that the InZnO, which does not contain Ga, can achieve high mobility, but has relatively poor stability under various instability environments. In this study, the TFTs using $IZO/Al_2O_3$ double layer structure were studied. The introduction of an $Al_2O_3$ interlayer between source/drain and channel causes superior electrical characteristics and electrical stability as well as reduced contact resistance with optimally perfect ohmic contact. For the IZO and $Al_2O_3$ bilayer structures, the IZO 30nm IZO channels were prepared at $Ar:O_2=30:1$ by sputtering and the $Al_2O_3$ interlayer were depostied with various thickness by ALD at $150^{\circ}C$. The optimal sample exhibits considerably good TFT performance with $V_{th}$ of -3.3V and field effect mobility of $19.25cm^2/Vs$, and reduced $V_{th}$ shift under positive bias stress stability, compared to conventional IZO TFT. The enhanced TFT performances are closely related to the nice ohmic contact properties coming from the defect passivation of the IZO surface inducing charge traps, and we will provide the detail mechanism and model via electrical analysis and transmission line method.

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Study on the change of performance of a-IGZO TFTs depending on processing parameters

  • 정유진;조경철;이재상;이상렬
    • 한국전기전자재료학회:학술대회논문집
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    • 한국전기전자재료학회 2009년도 추계학술대회 논문집
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    • pp.8-8
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    • 2009
  • Thin-film transistors (TFTs) were fabricated using amorphous indium gallium zinc oxide (a-IGZO) channels by rf-magnetron sputtering at room temperature. We have studied the effect of oxygen partial pressure on the threshold voltage($V_{th}$) of a-IGZO TFTs. Interestingly, the $V_{th}$ value of the oxide TFTs are slightly shifted in the positive direction due to increasing $O_2$ ratio from 1.2 to 1.8%. The device performance is significantly affected by varying $O_2$ ratio, which is closely related with oxygen vacancies provide the needed free carriers for electrical conduction.

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