• 한국진공학회지
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• 제20권6호
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• pp.430-435
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• 2011

고상 반응법을 사용하여 $Eu^{3+}$ 이온의 함량비를 변화시키면서 $Y_{1-x}PO_4:{Eu_x}^{3+}$ 적색 형광체를 합성하였다. 모든 적색 형광체의 결정 구조는 $25.88^{\circ}$에 중심을 갖는 (200) 주 회절 피크로 구성되는 정방정계이었으며, 결정 입자의 형상은 $Eu^{3+}$ 이온의 함량비가 증가함에 따라 구형에 근접하고 균일한 크기 분포를 나타내었다. 형광 특성의 경우에, $Eu^{3+}$ 이온의 함량비에 관계없이 모든 세라믹은 파장 593.0과 619.2 nm에 피크를 갖는 각각 적주황색과 적색 형광을 나타내었다. $Eu^{3+}$ 이온의 함량비가 증가함에 따라 여기 스펙트럼의 파장은 약간씩 장파장 쪽으로 이동하면서 흡수 세기는 증가하는 경향을 보였으며, $Eu^{3+}$ 이온의 함량비가 0.15 mol일 때 최대 흡수 및 발광 스펙트럼이 관측되었다.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2013년도 제45회 하계 정기학술대회 초록집
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• pp.281.2-281.2
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• 2013

Since heavy metal ions included in water or food resources have critical effects on human health, highly sensitive, rapid and selective analysis for heavy metal detection has been extensively explored by means of electrochemical, optical and colorimetric methods. For example, quantum dots (QDs), such as semiconductor QDs, have received enormous attention due to extraordinary optical properties including high fluorescence intensity and its narrow emission peaks, and have been utilized for heavy metal ion detection. However, the semiconductor QDs have a drawback of serious toxicity derived from cadmium, lead and other lethal elements, thereby limiting its application in the environmental screening system. On the other hand, Graphene oxide (GO) has proven its superlative properties of biocompatibility, unique photoluminescence (PL), good quenching efficiency and facile surface modification. Recently, the size of GO was controlled to a few nanometers, enhancing its optical properties to be applied for biological or chemical sensors. Interestingly, the presence of various oxygenous functional groups of GO contributes to opening the band gap of graphene, resulting in a unique PL emission pattern, and the control of the sp2 domain in the sp3 matrix of GO can tune the PL intensity as well as the PL emission wavelength. Herein, we reported a photoluminescent GO array on which heavy metal ion-specific DNA aptamers were immobilized, and sensitive and multiplex heavy metal ion detection was performed utilizing fluorescence resonance energy transfer (FRET) between the photoluminescent monolayered GO and the captured metal ion.

• Journal of Korean Vacuum Science & Technology
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• 제5권1호
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• pp.7-10
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• 2001

Ion induced secondary electron emission coefficients γ of protecting layers of an AC plasma display panel(AC-PDP) have been measured. In order to solve the surface charging effect during the measurement at insulating samples like MgO, a new method with the patterned gold line charge neutralization has been introduced. The measurement was performed at the samples, MgO and MgO+MgF$_2$, which showed a great difference in the firing voltage between the two protecting layers. The γ value has been compared with the firing voltage Vf of the AC-PDP with the same protecting layer. Correct relationship between γ and Vf has been observed. Thus, the patterned gold line method has been proven to be successful for the measurement of the secondary electron emission yield at insulator sample surfaces.

• 한국연소학회지
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• 제4권2호
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• pp.35-41
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• 1999

The purpose of this study is to establish the flame structure and NOx emission characteristics of the swirl flow coaxial diffusion combustion in the model gas turbine combustor. The mean temperature, ion currents and NOx emission measurement technique showed the effect of equivalence ratio into flame length and flame stability. As a result of this study, NOx emission was increased by increasing the equivalence ratio, and the peak value of the NOx was appeared near the flame front.

• 한국정보디스플레이학회:학술대회논문집
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• 한국정보디스플레이학회 2006년도 6th International Meeting on Information Display
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• pp.1355-1359
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• 2006

Due to its efficient red emission, $Eu^{3+}$ ion has been doped in various host materials. $GdCa_4B_3O_{10}:Eu^{3+}$ phosphor for red emission has been prepared by solid state reaction. Photoluminescence properties for the phosphor under UV and VUV excitation were investigated. The $GdCa_4B_3O_{10}:Eu^{3+}$ phosphor under both excitation conditions shows typical red emission spectrum centered at 611 nm with several weak peaks due to energy transfer from $^5D_O\;to\;^7F_J(J=1,2,3,4)$ of $Eu^{3+}$ ion. On the other hand, the activator content exhibiting the concentration quenching under UV and VUV irradiation is 10 mole% and 2.5 mole%, respectively.

• 분석과학
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• 제11권3호
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• pp.194-201
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• 1998

목재 및 철재기구로부터 방출된 포름알데히드를 증류수에 흡수시키고 아세틸아세톤법을 사용하여 정량하였다. 실온에서 시간 경과에 따른 방출량의 변화를 보았다. 50 mL 병에 목재 및 철재를 넣고 방출된 휘발성 유기 물질을 ion-trap GC-MS를 이용하여 정량하였다.

• Bulletin of the Korean Chemical Society
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• 제8권2호
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• pp.115-118
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• 1987

The angular dependence of polarization of the A-band emission from RbCl:$Pb^{2+}$ is measured at 13.4 K to determine the symmetry axes of the $Pb^{2+}-v^-_c$ dipoles. The results indicate that these centers posess tetragonal symmetry. This implies that $v^-_c$ is situated in the next-nearest-neighbor (nnn) position to the $Pb^{2+}$ ion. The polarization ratio of the A-band emission measured at various temperatures is found to be independent of the temperature. The temperature independence of polarization confirms that, for the ion, the Jahn-Teller effect reduced by strong spin-orbit interaction does not give rise to thermal depolarization.

• 한국자기학회지
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• 제21권5호
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• pp.163-166
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• 2011

기계적 자유도(mechanical degrees of freedom)를 가지는 free-standing 박막의 전계 방출 특성을 연구하였다. Free-standing 박막에서의 전계 방출 효과를 보다 정확히 해석하기 위하여 기계적 자유도(mechanical degrees of freedom)를 고려한 Fowler-Nordheim 전계 방출 식을 유도하였다. 새롭게 유도된 Fowler-Nordheim 식은 실험값과 매우 잘 일치한다. 이러한 free-standing 박막에서의 전계 방출 효과를 이용하여 이온화된 생체 분자의 충돌로 인해 발생된 free-standing 박막의 고주파 기계적 진동을 탐지함으로써 단백질 질량 분석기의 디텍터로 활용될 수 있음을 보였다.

• 한국정보디스플레이학회:학술대회논문집
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• 한국정보디스플레이학회 2003년도 International Meeting on Information Display
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• pp.799-801
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• 2003

The secondary electron emission $coefficient({\bullet})$ of vacuum annealed MgO films has been investigated by ${\bullet}$ -focused ion beam(${\bullet}$ -FIB) system. The vacuum annealed MgO films have been found to have higher ${\bullet}$ values than those for as-deposited MgO films for Ne+ ion. Also it is found that the ${\bullet}$ for air-hold of vacuum annealed MgO layers for 24-hours is similar to that for vacuum annealed MgO films without any air-hold.

• 한국전기전자재료학회논문지
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• 제20권5호
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• pp.456-461
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• 2007

In this study, a surface treatment method using accelerated Ar ions was experimented for exposing the carbon nanotubes (CNT) from the screen-printed CNT paste. After making a cathode electrode on the glass substrate, photo sensitive CNT paste was screen-printed, and then back-side was exposed by UV light. Then, the exposed CNT paste was selectively remained by development. After post-baking, the remained CNT paste was bombarded by accelerated Ar ions for removing some binders and exposing only CNTs. As results, the field emission characteristics were strongly depended on the accelerating energy, bombardment time, and the power of RF plasma ion source. When Ar ions accelerated with 100 eV energy from the 100 W RF plasma source are bombarded on the CNT paste surface for 10 min, the emission level and the uniformity were best.