• Title/Summary/Keyword: 최적입도

Search Result 174, Processing Time 0.026 seconds

Synergy Effect of Sun Protection Factor Using Method of Forming Self-Assembly of Hybrid Titanium Dioxide (하이브리드 이산화티탄의 자기조직체 형성공법을 이용하여 제조된 하이브리드 이산화티탄의 자외선차단 상승효과)

  • Cho, Hyun Dae;Park, Soo Nam
    • Journal of the Korean Applied Science and Technology
    • /
    • v.31 no.4
    • /
    • pp.748-758
    • /
    • 2014
  • The purpose of this study is to find the optimum conditions for manufacturing titanium dioxide using a hybrid self-assembly forming method, to confirm the shape, properties and synergy effect of UV protection for hybrid titanium dioxide. Hybrid titanium dioxide, manufactured by forming self-assembly of different sizes consisting of two kinds of titanium dioxides, has micro titanium dioxide (250nm~300nm) for support material, Nano titanium dioxide (20~30nm) for surface material, coating support material. Adjustment experiments of $AlCl_3$ concentration and both titanium dioxide ratio were conducted to find the optimized conditions for the surface coating of titanium dioxide striking a negative charge, a sample made of the optimized process was confirmed through an optical analysis, particle size analysis, and potentiometric analysis. The SPF in-vitro value of the cosmetics samples containing hybrid titanium dioxide showed 15~30% higher levels than the cosmetics samples containing both titanium dioxides mixture.

Dispersion Characteristics Control of $TiO_2$ Nano Particles for Electronic Paper (전자 종이 적용을 위한 $TiO_2$나노 입자의 분산 특성 제어)

  • 권순형;김세기;홍완식;안진호;김선재
    • Proceedings of the Materials Research Society of Korea Conference
    • /
    • 2003.03a
    • /
    • pp.127-127
    • /
    • 2003
  • 전자종이에 대한 관심이 높아지면서 전자잉크의 pigment 소재에 대한 연구가 최근 활발하게 이루어지고 있다. 많은 재료 중 TiO$_2$는 비표면적이 크고 열적안정성 및 명암도가 뛰어나 전자잉크 재료로 많은 장점을 지닌다. TiO$_2$ 나노 입자를 전자종이에 적용할 경우 우수한 디스플레이 구현을 위해 높은 전기영동 특성 및 분산 안정성이 요구되어진다 이를 위해 표면 개질된 나노 크기의 루틸상 TiO$_2$ 입자의 제조 및 분산에 대한 최적의 공정조건에 대해 연구하였다. 10$0^{\circ}C$ 이하의 저온에서 가열하여 균일하게 침전시키는 저온균일침전법(HPPLT)으로 루틸 결정상의 TiO$_2$ 나노입자를 제조하였다. 제조된 TiO$_2$ 나노 입자와 용매의 비중을 맞추기 위해 비중이 낮은 투명성 polymer로 코팅을 한 후 비중병을 이용해 비중을 확인하였다. 그 후 copolymer block을 가지는 분산제를 TiO$_2$ 입자 기준 0.5-5wt% 범위에서 저유전율을 가지는 다양한 유기용매에 첨가하여 최적의 분산 및 전기영동 조건을 찾았다. 실험을 통한 분산안정성 및 전기영동 특성 평가를 위해 ζ-potential analyzer와 입도 분석기를 이용하였고 코팅된 입자의 표면상태는 FT-IR을 통해 측정하였다.

  • PDF

Study of Preparation of $BaTiO_3$Powder using Hydrothermal methods (수열합성법에 의한 $BaTiO_3$분말합성)

  • 남성찬;박정훈;김종기;박상도
    • Proceedings of the Korea Society for Energy Engineering kosee Conference
    • /
    • 2001.11a
    • /
    • pp.219-224
    • /
    • 2001
  • BaTiO$_3$분말을 barium hydroxide, meta titan acid를 이용하여 광화제 첨가 없이 열수처리에 의한 탈수(dehysration) 및 재경정화(recrystallization)과정으로 수열합성법에 의해 제조하였다. Autoclave 반응기를 이용한 실험의 경우, BaTiO$_3$분말을 생성하기 위한 최적 온도 및 반응시간은 각각 18$0^{\circ}C$, 4시간으로 확인되었으며, 이 때 생성된 BaTiO$_3$분말의 크기는 0.1~0.2$\mu\textrm{m}$로 입도분포가 양호하였다. 그리고, 광하제의 영향을 살펴보면 광화제를 사용하지 않았을 경우가 1.0MK KOH를 첨가하였을 때보다 결정성이 우수하게 나타났다. 이와같은 결과로부터 수열합성조건에서 Ba와 Ti의 출발물질이 [-OH]기를 가지고 있는 경우, 원료의 용해도를 증가시키고 출발물질의 수산기(hydroxide)의 생성이 용이하여 광화제의 첨가 없이도 BaTiO$_3$분말을 합성할 수 있음에 따라 공정단순화를 통해ㅐ 에너지 절감 효과를 가져올 수 있었다.

  • PDF

Suggesting Blasting Design for Kazakhstan mine using Korea Mining Technology (국내 광산 기술을 적용한 카자흐스탄 광산 발파설계 제안)

  • Jin, Yeon-Ho;Min, Hyung-Dong;Jeong, Min-Su;Park, Yoon-Suk;Heo, Eui-Haeng;Nurmatov, Murod
    • Explosives and Blasting
    • /
    • v.32 no.1
    • /
    • pp.10-17
    • /
    • 2014
  • In this study, the information achieved from the visit to Kazakhmys mine in Kazakhstan was introduced. An optimal blasting pattern designed for the mine with the application of Korean blast technology was suggested. As a result, it was found that the blast design can reduce the consumption of explosives and the number of drill holes. The blast design can reduce the overall production cost in the mine.

The Developement of Non-toxic Black Pigments Unused Cr(VI) (중금속($Cr^{+6}$) 사용하지 않은 무독성 블랙안료의 개발)

  • Do, Young-Woong;Ha, Jin-Wook
    • Proceedings of the KAIS Fall Conference
    • /
    • 2010.05b
    • /
    • pp.957-960
    • /
    • 2010
  • 본 연구에서는 중금속 크롬($Cr^{+6}$)이 포함된 흑색안료(Copper Chromite Black)를 공침공정을 이용하여 무독성의 Fe 화합물로 대체한 환경친화적인 블랙(흑색)안료를 개발하였다. 안료제조를 위하여 인체에 무해한 화합물($MnCO_3$, Fe(OH)$_3$, CuO)을 원료로 사용하였으며, 가스소성, Ring-Mill에 의한 습식분쇄 그리고 건조과정을 통하여 흑색안료를 제조하였다. 안료의 평가는 제품의 품질을 결정하는 색상과 착색력을 최우선으로 선정하여 색차계로 고찰하였다. 연구결과, 공침공정으로 제조한 원료를 $950^{\circ}C$에서 12시간 동안 가스소성을 한 후 건조와 분쇄공정(습식)을 거쳐 흑색안료를 제조하였을 때, 최적의 색 선명도, 착색력 및 입도($1{\mu}m$ 이하)를 가진 것으로 나타났다.

  • PDF

Improvement of Magnetic Properties of Nd-Fe-B Type Sintered Magnet (Nd-Fe-B계 소결자석의 자기적특성 향상 연구)

  • Kim, Yoon-B.;Jung, W.S.;Jeung, W.Y.
    • Journal of the Korean Magnetics Society
    • /
    • v.12 no.2
    • /
    • pp.57-63
    • /
    • 2002
  • In order to increase the magnetic properties of a Nd-Fe-B sintered magnet, the general factors including particle size and its distribution, volume fraction of Nd$_2$Fe$_{14}$B phase, degree of alignment of Nd$_2$Fe$_{14}$B grain, oxygen content and grain size etc. should be optimized by controlling the composition of Nd-Fe-B alloy as well as the manufacturing process. In this study, fabrication of the Nd-Fe-B sintered magnet was carried out in a laboratory scale by controlling the composition of Nd-Fe-B alloy and the manufacturing process. The optimum milling condition was found by investigating the milling media, milling time and ball size. The addition of FeGa was effective to increase the coercivity of the Nd-Fe-B sintered magnet. A remanence of 14.4 kG, a coercivity of 9.4 kOe and a maximum energy product of 47 MGOe were obtained from the sintered magnet.

인천국제공항(IIA)의 다짐시험시공 결과 및 적용

  • 김영웅;김용철
    • Geotechnical Engineering
    • /
    • v.14 no.5
    • /
    • pp.235-247
    • /
    • 1998
  • The IIA(Inchon International Airport) which will function as the HUB airport in the northeast Asian region in the upcoming 21th century will be located in the reclaimed land with sand dredged in the vicinity of project area between Youngjong and Yongyu islands. The original ground is composed of soft clayey silt (ML) or silty clay (CL). The reclaimed land is classified as being SP-SM and having poor gradation of Cu<3 which resulted in the anticipation for difficulty in compaction (compaction index = 0.6~0.7). This anticipation shedded light on the necessity of performing test compactions for the thickness of 3~5meters of reclaimed land, aiming at the discovery of effective and economical compaction method. Upon the call for the test compaction performance 4 different compaction methods have been selected for trial from the research done on the international and local academic papers, past experience with compaction works, and their written materials. For the precise interparetation of test results, the ground survey and measurements have been performed. The Hydraulic Hammer Compaction has been chosen as the most optimum in accordance withe the test results.

  • PDF

The Study on the Preparation of the Silica Particles by the Reactive Crystallization (반응 결정화에 의한 실리카 미립자 합성에 관한 연구)

  • Kim, Jun Ho;Lee, Chang Hwan;Lee, Choul Ho
    • Applied Chemistry for Engineering
    • /
    • v.17 no.1
    • /
    • pp.12-15
    • /
    • 2006
  • The purpose of this study was to investigate the effect of reaction conditions, solvents, and surfactants on the average size and size distribution of silica particles in preparing silica fine powders by sodium silicate. Silica fine particles were synthesized by varying kinds of solvents and surfactants using the emulsion method. Span 20, Span 40, Span 60, and Span 80 were used as nonionic surfactants, Dispersing solvents were n-Hexane, n-Heptane, iso-Octane, and n-Decane of the alkane group. In these experiments, it was known that the optimum dispersion stirring time to form the emulsion of the constant size was around 6 min. The mean sizes of silica particles, at a variety of the dispersion stirring speeds, decreased as the dispersion stirring speed increased. Also, in the case of the solvents, the size of the formed silica particles decreased when the molecular weight of the solvent increased. Lastly, in the case of the surfactants, the mean size of silica particles increased as the hydrophobic lipophilic balance (HLB) value of the surfactant decreased.

Taguchi's Robust Design Method for Optimization of Grinding Condition by Hammer Mill (다구치 방법을 활용한 해머밀 분쇄공정의 최적화 연구)

  • Choe, Hong-Il;Kim, Byoung-Gon;Park, Chong-Lyuck;Jeong, Soo-Bok;Jeon, Ho-Seok;Jang, Hee-Dong
    • Journal of the Mineralogical Society of Korea
    • /
    • v.23 no.3
    • /
    • pp.219-225
    • /
    • 2010
  • Optimal grinding condition was examined by changing only the size of screen opening with fixing other factors to produce coal fines of particle sizes required for circulating fluidized bed gasifier. At least 85 wt% of the coal particles should fall into the size range of 0.045~1.0 mm for efficient gasification. In this study, hammer mill was used to grind Chinese low rank lignite coal following grinding condition designed by Taguchi method. The analysis of signal to noise ratio showed that optimum grinding condition for the gasifier was 3 mm in primary screen size and 1.3 mm in secondary screen size on the 95% level of significance.

A Study on the Quality Characteristics of Morning Buns Made from Different Particle Sizes of Goami Powder (입도가 다른 고아미 가루로 만든 모닝빵의 품질 특성에 관한 연구)

  • Kim, Hyun-Ah;Lee, Kwang-Suck
    • Culinary science and hospitality research
    • /
    • v.17 no.5
    • /
    • pp.218-230
    • /
    • 2011
  • The purpose of this study was to increase the consumption of rice rich in dietary fiber, Goami, substituted for flour in making morning buns. Goami powder was prepared in different particle sizes by grinding 5 min. 10 min. 15 min. 20 min. To determine the optimal water quantity of Goami powder dough for morning buns, the hardness of the flour and the Goami powder dough was measured. The appropriate water quantity of Goami powder morning buns was set at 119 mL ~ 218 mL. GB4 had the highest fermentation rate after 60 mim. fermentation. The volume index of the flour morning buns was the highest. The flour morning buns and GB4 showed about the same hardness. The L-values of flour morning buns were higher than those of the Goami powder morning buns. In the sensory evaluation, the overall preference was the highest in the flour morning buns. Among the Goami powder morning buns, GB3 and GB4, grinded for 15 min., were the most preferred.

  • PDF