• 대한기계학회논문집B
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• 제31권6호
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• pp.539-546
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• 2007

An experimental study was performed to investigate the characteristics of chemiluminescence in a radiant burner, varying the excess air ratio from 0.91 to 1.67 at firing rate 80.5 to 134.2 kW/m2 on $OH^*,\;CH^*,\;{C_2}^*$ in LNG-Air premixed flames. The signals from electronically excited states of $OH^*,\;CH^*,\;{C_2}^*$ were detected using a Intensified Couple Charged Detector (ICCD) camera. The measurements of exhausted emission were made to investigate the correlation between chemiluminescence and emissions. The chemiluminescence intensity was increased with increase of firing rate like characteristics of $NO_x$ emission. $NO_x$ also increased with increase of firing rate and excess air ratio. It is found that offset of firing rate is more dominant excess air ratio $NO_x$ emission. The maximum chemiluminescence intensity occurs near the stoichiometric excess air ratio or lean conditions in case of high firing rate and the maximum intensity occurs rather than rich conditions in case of relatively low firing rate. Amount of $NO_x$ emission is maximum at near stoichiometric excess air ratio, which is chemiluminescence intensity is maximum.

• 소음진동
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• 제6권6호
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• pp.843-849
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• 1996

Locations and emission characteristics of noise source of motor vehicles are great important factors to control the road traffic noise in effective ways. From results of this study on emission characteristics of engine and exhaust noise, we could find that every noise emission of different kind of vehicles has smilar pattern. The main emission locations of engine noise for the front of vehicle became the space between the road surface and bottom of the body and radiator grill, and for the side of vehicle became the space between the road surface and bottom nearby the front wheel. In case of exhaust noise of passenger-car and light truck, all the highest sound intensity level located near surface of road. But it is hard to conclude the height of noise source of driving vehicles with only results of this study. So further studies are needed to check the emission characteristics of noise.

• Current Optics and Photonics
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• 제5권4호
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• pp.450-457
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• 2021

Upconversion (UC) properties of Y₂O₃:Ho³⁺/Yb³⁺ spherical particles synthesized by spray pyrolysis were investigated by changing the dopant concentration and calcination temperature. Citric acid (CA), ethylene glycol (EG) and N, N-dimethylformamide (DMF) were used to control the microstructure of Y₂O₃:Ho³⁺/Yb³⁺ particles. In terms of achieving the highest UC green emission intensity, the optimal concentrations of Ho³⁺ and Yb³⁺ were found to be 0.3% and 3.0%, respectively. In addition, the UC intensity of Y₂O₃:Ho³⁺/Yb³⁺ showed a linear relationship with the crystallite size. The use of organic additives allows Y₂O₃:Ho³⁺/Yb³⁺ particles to have a spherical and dense structure, resulting in significantly reducing the surface area while maintaining high crystallinity. As a result, the UC emission intensity of Y₂O₃:Ho³⁺/Yb³⁺ particles having a dense structure showed the UC emission intensity about 3.8 times higher than that of hollow particles prepared without organic additives. From those results, when Y₂O₃:Ho³⁺/Yb³⁺ particles are prepared by the spray pyrolysis process, the use of the CA/EG/DMF mixtures as organic additives has been suggested as an effective way to substantially increase the UC emission intensity.

• 한국표면공학회지
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• 제38권2호
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• pp.73-78
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• 2005

A real-time monitoring of ICP(inductively coupled plasma) assisted magnetron sputtering of MgO was carried out using a QMS(quadrupole mass spectrometer), an OES(optical emission spectrometer), and a digital oscilloscope with a high voltage probe and a current monitor. At the time of ICP ignition, the most distinct impurity was OH emission (308.9 nm) which was dissociated from water molecules. For reactive deposition oxygen was added to Ar and the OH emission intensity was reduced abruptly When the discharge voltage was regulated by a PID controller from 240V(metallic mode) to 120V(oxide mode), the emission intensity from Mg (285.2 nm) changed proportionally to the discharge voltage, but the intensity of Ar I(811.6 nm) was constant. At 100V of discharge voltage, Mg sputtering was almost stopped. Emissions from Ar I(420.1 nm) and Mg I were dropped down to 1/10, but Ar I(811.6 nm) didn't change. And the emission from atomic oxygen (O I, 777.3 nm) was increased to 10 times. These results are compatible with those from QMS study.

• Bulletin of the Korean Chemical Society
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• 제25권1호
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• pp.73-78
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• 2004

A highly sensitive detecting method has been developed for determining part per billion of sulfur in $H_2S$/Ar plasma. The method is based on the excitation of Ar/$H_2S\;or\;Ar/H_2S/O_2$ mixture in hollow cathode glow discharge sustained by radiofrequency (RF) or 60 Hz AC power and the spectroscopic measurement of the intensity of emission lines from electronically excited $S_2^*\;or\;SO_2^*$ species, respectively. The RF or AC power needed for the excitation did not exceed 30 W at a gas pressure maintained at several mbar. The emission intensity from the $SO_2^*$ species showed excellent linear response to the sulfur concentration ranging from 5 ppbv, which correspond to S/N = 5, to 500 ppbv. But the intensity from the $S_2^*$ species showed a linear response to the $H_2S$ only at low flow rate under 20 sccm (mL/min) of the sample gas. Separate experiments using $SO_2$ gas as the source of sulfur demonstrated that the presence of $O_2$ in the argon plasma is essential for obtaining prominent $SO_2^*$ emission lines.

• Journal of Ceramic Processing Research
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• 제20권1호
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• pp.80-83
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• 2019

The Mn4+-activated Li2ZnSn2O6 (LZSO:Mn4+) red phosphors were synthesized by the solid-state reaction at temperatures of 1100-1400 ℃ in air. The synthesized LZSO:Mn4+ phosphors were confirmed to have a single hexagonal LZSO phase without the presence of any secondary phase formed by the Mn4+ addition. With near UV and blue excitation, the LZSO:Mn4+ phosphors exhibited a double band deep-red emission peaked at ~658 nm and ~673 nm due to the 2E → 4A2 transition of Mn4+ ion. PL emission intensity showed a strong dependence on the Mn4+ doping concentration and the 0.3 mol% Mn4+-doped LZSO phosphor produced the strongest PL emission intensity. Photoluminescence emission intensity was also found to be dependent on the calcination temperature and the optimal calcination temperature for the LZSO:Mn4+ phosphors was determined to be 1200 ℃. Dynamic light scattering (DLS) and field-effect scanning electron microscopy (FE-SEM) analysis revealed that the 0.3 mol% Mn4+-doped LZSO phosphor particles have an irregularly round shape and an average particle size of ~1.46 ㎛.

• 무역학회지
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• 제47권3호
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• pp.157-175
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• 2022

This study calculates agglomeration indices of manufacturing specialization and diversification in different regions of South Korea. Two types of agglomeration indices are introduced into the spatial durbin model (SDM) to analyzes the effects of manufacturing agglomeration in Korea on CO₂ emission intensity. The subjects of this study are 17 regions of South Korea , and the research period is from 2013 to 2019. This study also uses partial differential to analyze the direct and spillover effect of specialization and diversification agglomeration on CO₂ emission intensity. From the perspective of direct effect, the results reveal that specialization agglomeration is an important factor contributing to Korea's CO₂ emissions. However, diversification agglomeration has an obvious CO₂ emission reduction effect. From the perspective of spillover effect, this study finds that specialization agglomeration in one region can also contribute to CO₂ emissions in nearby regions. However, the development of diversification agglomeration in one region can have CO₂ emission reduction spillover effect on neighboring regions.

• 자원ㆍ환경경제연구
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• 제20권2호
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• pp.229-254
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• 2011

본 논문은 LMDI(Log Mean Divisia Index) 방법론을 이용하여 국내 제조업의 온실가스 배출에 대한 요인분해분석을 하였다. 국내 제조업의 온실가스 배출에 대한 요인분해는 크게 생산효과, 구조효과, 집약도효과, 에너지믹스효과, 배출계수효과 등 다섯 가지 요인으로 분해하였다. 1991년~2007년까지 국내 제조업의 온실가스 배출변화 요인을 분석한 결과를 보면 국내 제조업의 온실가스 배출은 대부분 생산효과에 의해서 증가하였다. 구조효과와 집약도는 온실가스 배출을 줄이는 역할을 하였으며, 구조효과보다는 집약도효과가 더 많이 온실가스 배출을 감소시키는 방향으로 작용하였다. 그리고 에너지믹스효과와 배출계수효과는 다른 효과들에 비해서 그 비중이 작지만 온실가스 배출 증감에 영향을 미치고 있다. 에너지믹스효과는 온실가스 배출 증가 요인으로 배출계수효과는 감소요인으로 작용하였다. 한편 시계열로 에너지 소비를 요인분해 해 본 결과 1998년 IMF 체제를 전후로 온실가스 패턴에 변화가 일어났다. IMF 체제 이후로 구조효과와 집약도효과에 의한 온실가스 감축이 IMF 체제 이전보다 더욱 두드러진 것이 특징이다. 2001년 이후 진행된 신고유가 시대를 맞이해서는 구조효과와 집약도효과가 더욱 촉진되었다.

• Bulletin of the Korean Chemical Society
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• 제25권4호
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• pp.525-528
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• 2004

The photoluminescence (PL) emission of Si nanocrystals synthesized by 400 keV Si ion implanted in $SiO_2$ is studied as a function of ion dose and annealing time. The formation of nanocrystals at around 600 nm from the surface was confirmed by RBS and HRTEM, and the Si nanocrystals showed a wide and very intense PL emission at 700-900 nm. The intensity of this emission showed a typical behaviour with a fast transitory increase to reach a saturation with the annealing time, however, the red shift increased continuously because of the Ostwald ripening. The oversaturation of dose derived a decrease of PL intensity because of the diminishment of quantum confinement. A strong enhancement of PL intensity by H passivation was confirmed also, and the possible mechanism is discussed.

• 한국공작기계학회논문집
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• 제16권6호
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• pp.163-167
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• 2007

A field emission electron gun including 3 electrodes including one cathode and two anodes is very important for high resolution electron microscope. To have functions to control the initially-emitted electron beam, two anodes act as an electrostatic lens according to equipotential lines by adjusting the spot size, intensity, and working distance. To verify the action of the electron beam by the electrostatic lens by changing several parameters such as electrode shape, displacement and applied voltage to the electrodes, the two lenses were design and simulated and then their performances were analyzed with angular beam intensity(distribution), electrical optic axis variation and their stability.