• 제목/요약/키워드: Ba/F3

검색결과 349건 처리시간 0.024초

Relationship between PAHs Concentrations in Ambient Air and Deposited on Pine Needles

  • Chun, Man-Young
    • Environmental Analysis Health and Toxicology
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    • 제26권
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    • pp.4.1-4.6
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    • 2011
  • Objectives: This study was carried out to determine whether or not pine needles can be used as passive samplers of atmospheric polycyclic aromatic hydrocarbons (PAHs) using the correlation between accumulated PAH concentrations in air (Ca, ng/$m^3$) and those deposited on pine needles (Cp, ng/g dry). Methods: PAHs in ambient air was collected using low volume PUF sampler and pine needles was gathered at same place for 7 months. Results: A good correlation ($R^2$=0.8582, p<0.05) was found between Ca and Cp for PAHs with a higher gaseous state in air (AcPy, Acp, Flu, Phen, Ant, Flt, Pyr, BaA and Chry), but there was a poorer correlation ($R^2$=0.1491, p=0.5123) for the PAHs with a lower gaseous state (BbF, BkF, BaP, DahA, BghiP and Ind123). A positive correlation ($R^2$=0.8542) was revealed between the logarithm of the octanol-air partitioning coefficient ($logK_{oa}$) and Cp/Ca for the PAHs with a higher gaseous state in air, but there was a negative correlation ($R^2$=0.8131) for the PAHs with a lower gaseous state. The Ca-Cp model could not be used to estimate PAHs concentrations in air using deposited PAHs concentrations on pine needles, but the logKoa-Cp/Ca model could be used. Conclusions: It was found that pine needles can be used as passive samplers of atmospheric PAHs.

적층형 유전체 필터를 위한 저온 소결용 마이크로파 유전체 유전특성 (The Microwave Dielectric properties of Low Temperature Firing Temperature Ceramics for Multilayer Dielectric Filter)

  • 윤중락;이헌용;이석원
    • 한국전기전자재료학회:학술대회논문집
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    • 한국전기전자재료학회 2001년도 하계학술대회 논문집
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    • pp.993-996
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    • 2001
  • In the composition of 0.16BaO-0.15(Nd$\_$0.87/,Bi$\_$0.13/)$_2$O$_3$-0.69TiO$_2$$.$Glass [EG-2782] 3wt% addition sintered at 1080$^{\circ}C$, we could obtained microwave properties of dielectric constant $\varepsilon$$\_$r/= 80.1, quality factor Q ${\times}$ f = 810 (at 3.5 GHz]) and temperature coefficient of resonant frequency $\tau$$\_$f/ = -1.3 [ppm/$^{\circ}C$]

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Spin injection and transport properties of Co/Au/Y$Ba_2$$Cu_3$$O_y$ tunnel junctions

  • Lee, Kiejin;Kim, Sunmi;Ishibashi, Takauki;Cha, Deokjoon
    • Progress in Superconductivity
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    • 제3권1호
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    • pp.70-73
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    • 2001
  • We report the spin injection and transport properties of three terminal devices of Co/Au/$YBa_2$$Cu_3$$O_{y}$(F/N/S) tunnel junctions by injection of spin-polarized quaiparticles using a cobalt ferromagnetic injector. The observed current gain depends on the thickness of Au interlayer and is directly related to the nonequilibrium magnetization due to spin relaxation effects. The tunnel characteristic of a F/N/S tunnel junctions exhibited a zero bias conductance peak (ZBCP). The suppression of the ZBCP was observed due to the suppression of Andreev reflection at the interface, which is due to the spin scattering processes at the interface between a ferromagnetic and a d-wave superconductor.r.

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분노 경험 회상시 특성 분노 수준에 따른 뇌 기능 (Brain Function During Recall of Anger Experience According to the Level of Trait Anger)

  • 음영지;이경화;손진훈
    • 감성과학
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    • 제21권3호
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    • pp.49-60
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    • 2018
  • 특성 분노는 분노 경험과 관련된 개인의 심리 특성 중 하나로, 특성 분노가 높은 이들은 낮은 이들에 비해 더 자주, 더 강하게, 더 길게 분노를 경험한다. 본 연구의 목적은 분노를 경험하는 동안에 활성화되는 뇌 영역을 관찰하고, 활성화된 뇌 영역 중 특성 분노와 연관이 있는 영역을 확인하는 것이다. 본 연구에서는 실험 참가자 35명을 대상으로 과거에 분노했던 기억을 회상하여 분노를 유발하는 과제를 수행하는 동안의 뇌 기능을 측정하였다. 정서적 중립 사건을 회상하는 조건에 비해 분노 사건을 회상하는 조건에서 더 활성화된 뇌 영역은 우측 superior temporal gyrus (BA38), 좌측 inferior frontal gyrus (BA45), 우측 thalamus, 우측 insula (BA13), 양측 cuneus (BA17), 그리고 우측 cerebellum anterior lobe으로 나타났다. 분노 회상 시 뇌 활성화 정도와 특성 분노 점수 간 상관 분석 결과, 특성 분노 점수가 높을수록 분노 회상시 우측 insula의 활성화가 높았다. Insula가 정서 경험과 신체 내부감각수용기에서 오는 정보를 통합하여 자극에 대한 주관적인 느낌을 표상하는 영역으로 알려져 있으므로, 특성 분노가 높은 사람일수록 분노 자극에 대한 주관적인 느낌을 더 강하게 표상한다고 해석할 수 있다. 이 연구 결과는 분노의 개인차에 대한 뇌 기제를 규명한 것으로, 분노 및 분노 조절 관련 문제들에 대한 신경과학적 이해를 향상시키는데 기여할 것으로 기대된다.

고압용 X7R 적층 칩 캐패시터의 Er2O3 및 유리프릿 첨가에 따른 전기적 특성 (The Electrical Properties of High Voltage Mutilayer Chip Capacitor with X7R by addition of Er2O3 and Glass Frit)

  • 윤중락;김민기;정태석;우병철;이석원
    • 한국전기전자재료학회논문지
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    • 제21권5호
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    • pp.440-446
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    • 2008
  • To manufacture the MLCC with X7R for high voltage stability, $BaTiO_3-MgO-MnO_2-Y_2O_3$ with $(Ba_{0.4}Ca_{0.6})SiO_3$ glass frit was formulated. Based on this composition, the addition of $Er_2O_3$ showed that TCC(Temperature Coefficient Capacitance) at $85^{\circ}C$ was improved from 5 % to ${\sim}0\;%$, but the dielectric constant and IR (Insulation Resistance) were decreased. The glass frit improved the dielectric constant and IR, so the appropriate contents of $Er_2O_3$ and glass frit were 0.6 mol% and 1 wt%, respectively. It showed that the dielectric constant and RC constant were 2,550 and 2,000 (${\Omega}F$), respectively in the sintering condition at $1250^{\circ}C$ in PO2 $10^{-7}$ Mpa. The MLCC with $3.2{\times}1.6$ (mm) size and $1\;{\mu}F$ was also suited for X7R with the above composition.

A comparative study on the impact of Gd2O3 burnable neutron absorber in UO2 and (U, Th)O2 fuels

  • Uguru, Edwin Humphrey;Sani, S.F.Abdul;Khandaker, Mayeen Uddin;Rabir, Mohamad Hairie;Karim, Julia Abdul
    • Nuclear Engineering and Technology
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    • 제52권6호
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    • pp.1099-1109
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    • 2020
  • The performance of gadolinium burnable absorber (GdBA) for reactivity control in UO2 and (U, Th)O2 fuels and its impact on spent fuel characteristics was performed. Five fuel assemblies: one without GdBA fuel rod and four each containing 16, 24, 34 and 44 GdBA fuel rods in both fuels were investigated. Reactivity swing in all the FAs with GdBA rods in UO2 fuel was higher than their counterparts with similar GdBA fuel rods in (U, Th)O2 fuel. The excess reactivity in all FAs with (U, Th)O2 fuel was higher than UO2 fuel. At the end of single discharge burn-up (~ 49.64 GWd/tHM), the excess reactivity of (U, Th) O2 fuel remained positive (16,000 pcm) while UO2 fuel shows a negative value (-6,000 pcm), which suggest a longer discharge burn-up in (U, Th)O2 fuel. The concentration of plutonium isotopes and minor actinides were significantly higher in UO2 fuel than in (U, Th)O2 fuel except for 236Np. However, the concentration of non-actinides (gadolinium and iodine isotopes) except for 135Xe were respectively smaller in (U, Th)O2 fuel than in UO2 fuel but may be two times higher in (U, Th)O2 fuel due to its potential longer discharge burn-up.

금새우난초(Calanthe striata f. sieboldii Decne. ex Regel)종자의 비공생 발아 및 신초증식 (Asymbiotic germination and seedling growth of Calanthe striata f. sieboldii Decne. ex Regel)

  • 배기화;김수영
    • Journal of Plant Biotechnology
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    • 제42권3호
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    • pp.239-244
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    • 2015
  • 본 연구는 자생 난초과식물인 금새우난초의 기내 비대배 유도, 발아 및 배직경에 미치는 몇 가지 영향(NaOCl, 배지, 식물생장조절제)을 조사하기 위해 수행되었다. 1% NaOCl을 30분간 처리한 후 POM배지에 배양할 경우, 비대배 유도는 28.3%, 발아율은 54.8%, 배직경은 $205.8{\mu}m$로 가장 높게 조사되었다. NaOCl 무처리 종자를 POM배지에 배양할 경우, 비대배 유도는 8.5%, 발아율은 13.4%, 배직경은 $14.6{\mu}m$로 조사되었다. 또한 식물생장조절물질의 처리가 발아에 미치는 영향을 조사한 결과, 1.0 mg/L의 BA 처리구(95.6%)의 발아율은 대조구(54.5%)에 비해 1.75배 높게 조사되었다. AC와 sucrose의 처리 농도가 기내 식물체 생장에 미치는 영향을 조사한 결과, 엽장은 10 g/L의 sucrose 처리구에서 6.8 cm로 가장 길었고, 대조구는 3.3 cm로 가장 짧았다. 근장은 50 g/L의 sucrose 처리구에서 5.8 cm로 가장 길었고, 대조구는 1.7 cm로 가장 짧았다. 생중량과 건중량은 AC와 sucrose 처리구가 대조구에 비해 2~5배 이상 높은 결과를 보였다. 결과적으로 본 연구는 금새우난초의 기내 발아 및 증식에 미치는 몇 가지 요인에 관해 구체적인 결과를 제시하였고, 이러한 결과는 향후 자생 난초과식물의 증식 및 보존전략 개발에 중요한 기초자료로 제공 될 것이다.

$CF_4$/Ar 플라즈마에 의한 BST 박막 식각 특성 (Etching Characteristics BST Thin Film in $CF_4$/Ar Plasma)

  • 김동표;김창일;서용진;이병기;장의구
    • 한국전기전자재료학회:학술대회논문집
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    • 한국전기전자재료학회 2001년도 하계학술대회 논문집
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    • pp.866-869
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    • 2001
  • In this study, (Ba,Sr)TiO$_3$(BST) thin films were etched with a magnetically enhanced inductively coupled plasma(MEICP). Etching characteristics of BST thin films including etch rate and selectivity were evaluated as a function of the etching parameters such as gas mixing ratio, rf power, dc bias voltage and chamber pressure. The maximum etch rate of the BST films was 1700 $\AA$/min at Ar(90)/CF$_4$(10), 600 W/350 V and 5 mTorr. The selectivity of BST to PR was 0.6, 0.7, respectively. To analyze the composition of surface residue remaining after the etching, samples etched with different CF$_4$/Ar gas mixing ratio were investigated with X-ray photoelectron spectroscopy (XPS) and secondary ion mass spectrometry (SIMS). From the results of XPS and SIMS, there are chemical reaction between Ba, Sr, Ti and C, F radicals during the etching and remained on the surface.

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스퍼터링 방식에 의한 Y-Ba-Cu-O 고온 초전도 박박의 제작에 관한 연구 (A study on the fabrication of Y-Ba-Cu-O High Tc superconducting thin film by sputtering system)

  • 채기병;강기성;소대화
    • 한국전기전자재료학회:학술대회논문집
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    • 한국전기전자재료학회 1992년도 추계학술대회 논문집
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    • pp.81-83
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    • 1992
  • The superconducting thin films deposited on $SiO_x$ substrate by R.F magnetron sputter using $YBa_2Cu_3O_x$ single target have been made and annealed at $940^{\circ}C$ for 30 min. The thickness of films were 1000-2000${\AA}$ with a rate of 20-25${\AA}/min$ and superconducting properties of thin films depended on the compositions of pre-annealed the thin films. It has been analyzed by SEM photo-analysis and X-ray diffraction patterns of these samples obtained under the various conditions of this sputtering methods. and recognized the supperconducting thin films by electric properties.

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Clinical Application of Functional MRI : Motor Cortex Activities by Acupuncture

  • Choe, Bo-Young
    • 한국자기공명학회논문지
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    • 제6권2호
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    • pp.89-93
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    • 2002
  • We report a preliminary fMRI evidence of modulation of somatomotor areas by acupuncture in GB34 acupoint. GB34, located in the back of the knee, is known to be effective in recovering motor function after stroke. Using 3T MR scanner, functional MR imaging was performed in five normal volunteers in two stimulation paradigms; acupuncture manipulation on GB34 and sham points. Group analysis form five individuals showed that bilateral sensorimotor areas (BA 3,4,6 and 7) showed stimulation related BOLD signal contrast of approximately 6% whereas very few areas were activated when sham stimulation is given. Our results suggest that acupuncture fMRI study can be safely conducted in 3T environment and stimulation in GB34 modulate the cortical activities of the somatomotor area in human.

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