• 한국광학회:학술대회논문집
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• 한국광학회 1997년도 Advance Program of 14th optics andquantum Electronics conference, 1997제14 회 광학 및 양자전자 학술 발표회 논문 요약집
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• pp.50-50
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• 1997

• 한국진공학회지
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• 제15권6호
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• pp.624-629
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• 2006

Nd을 이온주입한 GaN를 이용하여 GaN와 Nd 이온 사이의 에너지 전달과정을 분석하고 Mg을 도핑 하였을 때의 효과를 보았다. Nd의 $^4F_{3/2}{\rightarrow}^4I_{9/2}$ 전이에 대하여 Photoluminescence (PL)와 PL excitation 방법을 이용하여 에너지 전달 경로에 적어도 3가지 이상의 밴드갭 내의 trap이 있음을 확인하였다. Mg이 doping된 GaN : Nd에서는 isoelectronic trap으로 생각되는 특정한 trap의 수가 증가되었음이 관측되었고 이로 인해 전기적으로 여기될 시료의 특성을 보여줄 밴드갭보다 큰 에너지를 이용한 여기 상태의 효율이 더욱 높아짐을 알 수 있었다.

• 한국정보디스플레이학회:학술대회논문집
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• 한국정보디스플레이학회 2004년도 Asia Display / IMID 04
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• pp.636-639
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• 2004

We have synthesized a $Eu^{2{\cdot}}$ -activated $Sr_3MgSi_2O_8$ blue phosphor and $Ba^{2{\cdot}}$ co-doped $Sr_2SiO_4$ yellow phosphor investigated an attempt to develop white LEDs by combining it with a GaN blue LED chip. Three distinct emission bands from the GaN-based LED and the ($Sr_3MgSi_2O_8$:Eu + $Ba^{2{\cdot}}$ co-doped $Sr_2SiO_4$:Eu) phosphor are clearly observed at 405nm, 455 nm and at around 540 nm, respectively. These three emission bands combine to give a spectrum that appears white to the naked eye. Our results show that GaN (405 nm chip)-based ($Sr_3MgSi_2O_8$:Eu + $Ba^{2{\cdot}}$ co-doped $Sr_2SiO_4$:Eu) exhibits a better luminous efficiency than that of the industrially available product InGaN (460 nm chip)-based YAG:Ce.

• 한국정보디스플레이학회:학술대회논문집
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• 한국정보디스플레이학회 2005년도 International Meeting on Information Displayvol.II
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• pp.1338-1342
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• 2005

We have synthesized an $Eu^{2+}$-activated $Sr_3MgSi_2O_8$ blue phosphor and $Ba_2SiO_4$ green phosphor and $Ba^{2+}$ co-doped $Sr_3SiO_5$ red phosphor investigated an attempt to develop white LEDs by combining it with a GaN blue LED $chip(\lambda_{em}=405 nm)$. Three distinct emission bands from the GaN-based LED and the $(Sr_3MgSi_2O_8:Eu\; +\; Ba_2SiO_4:Eu\; +\; Ba^{2+}\; co-doped\; Sr_3SiO_5:Eu)$ phosphor are clearly observed at 460nm, 520 nm and at around 600 nm, respectively. These three emission bands combine to give a spectrum that appears white to the naked eye. Our results show that GaN (405 nm chip)-based $(Sr_3MgSi_2O_8:Eu\; +\; Ba_2SiO_4:Eu\; +\; Ba^{2+}\; co-doped\; Sr_3SiO_5:Eu) exhibits a better luminous efficiency than that of the industrially available product InGaN (460 nm chip)-based YAG:Ce.

• Journal of Magnetics
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• 제21권1호
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• pp.61-64
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• 2016

In this study, we report the as-prepared MgO-doped $BaFe_{12}O_{19}$, which was prepared by calcination technique and high-energy ball milling process, as an electromagnetic wave absorber. The phase analysis of $BaFe_{12}O_{19}$ and the as-prepared MgO-doped $BaFe_{12}O_{19}$ was detected utilizing X-ray Diffractometer (XRD). The microstructure was characterized using Scanning Electron Microscope (SEM). By means of the transmission/reflection coaxial line method, the electromagnetic properties and microwave absorbing properties of the as-prepared electromagnetic wave absorber were studied. It is found that the electromagnetic wave absorber has a minimum reflection loss value of -41 dB at 4.27 GHz with a matching thickness of 2.6 mm. The experiment results revealed that the as-prepared electromagnetic wave absorber could find potential applications in many military as well as commercial industries.

• 한국결정성장학회지
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• 제33권4호
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• pp.132-138
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• 2023

Doped and undoped-BiVO₄ samples with different elements (Li, Mg) and amounts were synthesized with a hydrothermal method. The synthesized samples were characterized using various techniques including X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), UV-Vis diffusion reflectance spectroscopy (UV-Vis DRS), and photoluminescence (PL) spectroscopy. Photocatalytic activity of the samples was evaluated by measuring the degradation of methyl blue (MB) under visible light irradiation. The results indicated that the incorporation of Mg and Li into BiVO₄ caused lattice distortion, the presence of surface hydroxyl groups, a narrower band gap, and a reduced recombination ratio of photo-induced electron-hole pairs. Notably, the photocatalytic activity of Mg5%-Li5% co-doped BiVO₄ sample exhibited a significant improvement compared to that of undoped BiVO₄ sample.

• 센서학회지
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• 제27권4호
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• pp.221-226
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• 2018

Misfueling accidents significantly damage the engines of both gasoline and diesel vehicles, and should be avoided by rapid and accurate fuel discrimination. Gasoline fuel contains bioethanol. Thus, the detection of ethanol vapor produced by gasoline can be used to distinguish between gasoline and diesel. In the present study, Pt-doped $SnO_2$ hollow nanospheres, Mg-doped $In_2O_3$ hollow microspheres, and Pt-doped ZnO nanostructures have been used as gas sensors to discriminate between gasoline and diesel fuels. All three sensors are able to detect and discriminate between gases evaporating from gasoline and diesel. Among the sensors, the Mg-doped $In_2O_3$ hollow microspheres show a significant gas response (resistance ratio = 4.97) quickly (~3 s) after exposure to gasoline-evaporated gas at $225^{\circ}C$, but did not show any substantial response to diesel-evaporated gas. This demonstrates that gasoline and diesel fuels can be discriminated using small and cost-effective oxide semiconductor gas sensors.

• 한국광학회지
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• 제7권2호
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• pp.162-166
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• 1996

전왜재질 0.9 PMN/0.1PT에 각각 조성비율이 1%, 2%, 3%의 La이 첨가된 3종류의 재질을 광섬유에 부착하여 광섬유 전왜변환기를 제작하였다. 실험결과 La 3% 첨가된 재질의 전왜계수가 3.38kHz에서 3.87*$10^{-16}$(m/V)$^{2}$로 가장 크다는 것을 알 수 있었으며 La을 첨가함으로 해서 이력이 줄어듬을 알 수 있었다. La 3%인 재질로 구현된 광섬유 전계센서의 최소감지전계는 2.08(V/m).root.Hz였으며 가변영역 40dB 이상에 걸쳐서 선형성이 우수하였다.

• Bulletin of the Korean Chemical Society
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• 제19권9호
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• pp.927-933
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• 1998

Polycrystalline powder of vanadium-doped forsterite (Vδ $Mg_2SiO_4$) was synthesized by the $H_2O_2$-assisted sol-gel method. The vanadium dopant, which was added as VO$(OMe)_3$ in methanol, went through several redox reactions as the sol-gel reaction proceeded. Upon adding VO$(OMe)_3$ to a mixture of $Mg(OMe)_2$ and Si$(OEt)_4$ in methanol, V(V) reduced to V(IV). As hydrolysis reaction proceeded, the V(IV) oxidized all back to V(V). Apparently, some of the V(V) reduced to V(IV) during subsequent gelation by condensation reaction. The V(IV) remained even after heat treatment of the gel in highly oxidizing atmosphere. The crystallization of the xerogel around 880 ℃ readily produced single phase forsterite without any minor phase. Using the polycrystalline powder as feeding stock, single crystals of vanadium-doped forsterite were grown by the floating zone method in oxidizing or reducing atmosphere. The doping was limited in low level because of the high partitioning of the vanadium in liquid phase during melting. The greenish single crystal absorbed visible light of 700∼1100 nm. But, no emission was obtained in near infrared range.

• 한국세라믹학회:학술대회논문집
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• 한국세라믹학회 2000년도 춘계총회,특별강연,심포지움,연구발표회
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• pp.93.2-93.2
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• 2000