• 한국분무공학회지
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• 제10권2호
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• pp.10-17
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• 2005

The proposed research has been performed to know the characteristics of cutting fluid aerosol formation using Dual-PDA system in machining process. The cutting fluid aerosol size and concentration is common attributes that quantify the environmental intrusiveness or air quality contamination. The atomized cutting fluid aerosols can be affected to human health risk such as lung cancer and skin irritations. Even though cutting fluid can be improved the machining quality and productivity in a carefully. its use must be controlled and optimized carefully. This experimental works using Dual-PDA were performed to analyze the cutting fluid aerosol behaviors and characteristics in turning process using precise aerosol particle measuring system. The obtained experimental results profovide basic knowledge to develop the environmentally conscious machining process. This results cail be provided as a basis to estimate and control the hazardous cutting fluid aerosol in machining process.

• 한국결정성장학회지
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• 제31권6호
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• pp.264-269
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• 2021

본 연구는 공침법을 통하여 비정질 알루미늄 실리케이트 분말을 제조하였으며, 슬러리의 알루미늄 실리케이트 분말 함량 및 분산제 첨가량을 조절하여, 슬러리의 특성에 따른 분무 건조 알루미늄 실리케이트 과립 분말 제조의 영향 분석 및 최적화 연구를 진행하였다. 연구 결과, 알루미늄 실리케이트 슬러리의 분말 함량 27.5 wt% 이하, 슬러리의 분산제 첨가량 0.8 wt% 이상, pH 6~9의 중성 분위기의 슬러리에서 안정적으로 과립 분말이 제조되었으며, 슬러리의 분말 함량 20, 22.5 wt%에서 과립 분말의 평균 입도는 약 14 ㎛, 슬러리의 분말 함량 25, 27.5 wt%에서 과립 분말의 평균 입도가 약 19 ㎛인 것을 확인하였다. 분무 건조 과립 분말의 형상은 슬러리의 분산안정성 및 점도 영향을 받으며, 분말 함량이 높을수록 평균 입자 사이즈가 증가하는 것을 확인하였다.

• 한국분말재료학회지
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• 제27권2호
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• pp.146-153
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• 2020

The co-doping effect of aliovalent metal ions such as Mg²⁺, Ca²⁺, Sr²⁺, Ba²⁺, and Zn²⁺ on the photoluminescence of the Y₂O₃:Eu³⁺ red phosphor, prepared by spray pyrolysis, is analyzed. Mg²⁺ metal doping is found to be helpful for enhancing the luminescence of Y₂O₃:Eu³⁺. When comparing the luminescence intensity at the optimum doping level of each Mg²⁺ ion, the emission enhancement shows the order of Zn²⁺ ≈ Ba²⁺ > Ca²⁺ > Sr³⁺ > Mg²⁺. The highest emission occurs when doping approximately 1.3% Zn²⁺, which is approximately 127% of the luminescence intensity of pure Y₂O₃:Eu³⁺. The highest emission was about 127% of the luminescence intensity of pure Y₂O₃:Eu³⁺ when doping about 1.3% Zn²⁺. It is determined that the reason (Y, M)₂O₃:Eu³⁺ has improved luminescence compared to that of Y₂O₃:Eu³⁺ is because the crystallinity of the matrix is improved and the non-luminous defects are reduced, even though local lattice strain is formed by the doping of aliovalent metal. Further improvement of the luminescence is achieved while reducing the particle size by using Li₂CO₃ as a flux with organic additives.

• 공업화학
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• 제20권6호
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• pp.632-637
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• 2009

Pluronic F127을 함유한 poly(${\varepsilon}-caprolacton$) / ethyl cellulose (PCL/EC) 마이크로 캡슐을 분무건조법으로 제조하였다. 20% (w/v)의 pluronic F127 수용액을 수상으로, 5% (w/w)의 PCL/EC이 녹아있는 디클로로메탄(dichloromethane)을 유기상으로 이용하여 water-in-oil (W/O) 에멀젼을 제조하였고, 이를 분무건조하여 마이크로 캡슐을 얻어낼 수 있었다. 주사전자현미경과 입도분석기로 분석한 결과, 수 마이크로부터 수십 마이크로 크기의 마이크로 캡슐이 형성을 확인되었다. 시차주사열량측정기로 마이크로 캡슐의 상전이 온도를 조사한 결과, 마이크로 캡슐 제조 시 사용된 고분자들의 상전이 온도가 관찰되었다. 마이크로 캡슐의 온도 의존적 방출 특성은 $30{\sim}45^{\circ}C$에서 관찰하였으며, 수용성 염료인 fluorescein isothiocyanate-dextran (FITC-dextran)과 blue dextran을 방출모델시약으로 하였다. 온도가 증가할수록 마이크로 캡슐로부터 방출되는 양이 증가하였으며, 방출모델시약의 분자량이 작을수록 더 많이 방출되었다.

• 한국식품저장유통학회지
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• 제9권2호
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• pp.189-193
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• 2002

천연식초를 이용하여 분말식초의 제조방법을 개발하고자 부형제의 비율을 달리하여 제조한 분말식초의 품질특성을 평가하여 분말식초의 제조 가능성을 검토하였다. 혼합 피복 물질로 제조된 분말식초의 품질특성을 비교한 결과 $\beta$-cyclodextrin과 gum arabic이 2.5:7.5의 비율로 제조한 분말식초가 비교적 낮은 수분함량을 나타내었고 산도는 높은 수치를 나타내 식초를 포집하는 능력이 가장 좋은 것으로 나타났다. 또한 이 비율로 제조한 분말식초의 흡습성 또한 비교적 낮은 값을 나타내었으며 열안정성은 모든 시료가 높은 수치를 나타내 열에는 모두 안정함을 알 수 있었다. 주사 현미경으로 관찰한 분체의 형태는 모두 구형을 형성하여 분말식초에서 캡슐이 형성되었음을 알 수 있었다. 관능검사 결과도 신맛의 증가로 높은 점수를 받았다. 이상의 결과로 분말식초의 제조시 피복물질의 혼합비율별은 $\beta$-cyclodextrin 과 gum arabic을 2.5:7.5의 비율로 제조하는 것이 가장 우수한 것으로 나타났다.

• 한국정보디스플레이학회:학술대회논문집
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• 한국정보디스플레이학회 2002년도 International Meeting on Information Display
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• pp.807-810
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• 2002

$GdPO_4$:Tb phosphor particles with spherical shape and high photoluminescence were prepared by spray pyrolysis. The brightness of prepared $GdPO_4$:Tb under the vacuum ultraviolet(VUV) illumination was comparable with that of the commercial $Zn_2SiO_4$:Mn phosphor particles. The photoluminescence spectra of $GdPO_4$:Tb phosphor particles had maximum peak at 547 nm, and the sharp peaks at 480 nm, 580 nm, and 620 nm. The spherical morphology of prepared $GdPO_4$:Tb particles was completely maintained even after the posttreatment up to 1100 $^{\circ}C$. When the posttreatment temperature was over 1100 $^{\circ}C$, the particles did not have the spherical shape anymore. The average particle size of $GdPO_4$:Tb phosphor particles prepared by using $(NH_4)_2HPO_4$ was changed from 0.5 to 1.9 ${\mu}m$ and its effect on the PL intensity was investigated. It was found that the optimized $GdPO_4$:Tb particles have a good excitation spectrum comparable to that of the commercial $Zn_2SiO_4$:Mn phosphor particles under the VUV illumination from 140 to 220 nm. We concluded that the $GdPO_4$:Tb phosphor particles with spherical shape prepared by spray pyrolysis is a promising candidate for a green-emitting PDP phosphor.

• 한국결정성장학회지
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• 제24권3호
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• pp.127-132
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• 2014

$Y_2O_3$-BN 세라믹 복합체를 제작하기 위해서, 분말 입도 $3{\sim}10{\mu}m$인 $Y_2O_3$ 분말을 분산한 슬러리에 pH 조절제인 NaOH를 첨가하였으며 결합제로는 PVA, 가소제로는 PEG를, BN 분말과 혼합하고, 분무건조(spray drying)공정을 거쳐 $Y_2O_3$ 혼합 분말을 제조하였다. ${\O}14mm$ 크기의 $Y_2O_3$-BN 시편을 성형하고, $1550^{\circ}C$ 및 $1600^{\circ}C$에서 소결하여 $Y_2O_3$-BN 복합체를 제작하였다. BN 투입량과 소결온도의 변수에 따른 미세구조, 순도, 꺽임강도, 열팽창계수, 밀도, 체적저항, 내플라즈마 특성을 조사하였다.

• 한국잠사곤충학회지
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• 제40권2호
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• pp.143-149
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• 1998

For the application of silk sericin, silk sericin powders were prepared by various spray dry conditions and the characteristics of silk sericin/polyurethane mixed films were investigated. When the sericin was dried from the solution at higher inlet and outlet temperature, larger sizes of the powder particles were obtained. It was also found that inlet and outlet temperatures were important factors affecting the shape and surface characteristics of sericin power particle. The many holes and empty spaces were observed at the surface and cross section of sericin/PU mixed film. With the increase of the amount of sericin powder in the mixed films, the size and number of holes and empty spaces were increased. The thickness of sericin/PU mixed film was increased with the content of sericin powder. As the portion of sericin powder increase, the tenacity is decreased while the elongation slightly increased.

• 한국세라믹학회지
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• 제25권4호
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• pp.357-363
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• 1988

Ccompaction and sintering behavior of highly pure PSZ powders were investigated by laying the stress on the granulation processes. The particle size of coprecipitated PSZ powder was so fine that the agglomeration was severely formed during drying and calcing step and by this agglomeration differential sinering was occurred. The methanol dispersion of precipitates was the good method of avoiding severe agglomeration formed during drying process because of small surface tension than water. But perfect deagglomeraton was not possible due to high surface area of powders. So homogenization by granulation was needed, and among the method spray granulation was the most desirable to obtain homogeneous compacts and subsequent flaw-free ceramics.

• 한국기계가공학회지
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• 제15권5호
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• pp.117-124
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• 2016

In this paper, we developed a breather valve with a water mist system for use near an oil storage tank. Our process applied a water mist system to the flame arrester to evaluate the fire suppression characteristics. For the fire suppression evaluation of the water mist system, we evaluated the angle of the nozzle, fire suppression, spray particle size, flashback, fire suppression time, and fire suppression test of antifreeze. Through the fire suppression test, the best fire suppression nozzle used an angle of $140^{\circ}$, and the flashback phenomenon of flame arrester did not occur. The fire suppression time of water mist system time was within three seconds, and the antifreeze was no problem with the fire suppression.