• Title/Summary/Keyword: 분산입도

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Geochemical Dispersion and Enrichment of Fluvial Sediments Depending on the Particla Size Distribution (입도분포에 따른 하상퇴적물의 지구화학적 분산 및 부화)

  • 이현구
    • Economic and Environmental Geology
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    • v.32 no.3
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    • pp.247-260
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    • 1999
  • Geochermical characteristics of the fluvial sediments deprnding on particle size distribution size were investigated in the respect of majir, minor and rare eath element chemisitry. Ratios of $Al_{2}O_{3}/Na_{2}O$ and $K_{2}O/Na_{2}O$ of the sediments show the homogeneous valus, and partly positive correlation with $SiO_{2}/Al_{2}O_{3}$, respecively. Characteristics of minor element ratios (V/Ni, Cr/V, Ni/Co and Zr/Hf)are within the lower and narrow range. Thesesuggested that sediment sources may be acidic to intermediate granitic rock, and may be explained by simple weathering and sedimentation. With increasing SiO2 contents, concentrations of $Al_{2}O_{3}$, $Fe_{2}O_{3}$, CaO and MgO decreased, but those of $K_{2}O$ and $Na_{2}O$ increased, Concentrations of Ba, Be, Cs, Cu, Li, Ni, Sr, V and Zr show comparatively normal negative and some positive trends. Compared with the mean composition of granite, concentrations of $Al_{2}O_{3}$, $Fe_{2}O_{3}$, MnO, CaO and MgO in the sediments of the study area were highly enriced. Among some minor and rare earth elements, concentrations of As, Cd, Cu, and V were enriched, but those of Be, Ce, Rb, Sc, Sr and Zn were depleted when compared with average composition of granite. By decreasing of particle size fractions, SiO2, Rb and Sr conterts decreased, but concentrations of $Al_{2}O_{3}$, $Fe_{2}O_{3}$, CaO, MgO, $TiO_{2}$, MgO, $P_{2}O_{5}$, Be, Cu, Hf, Pb, V and Zr increased. From the correlations between particle size fractions and element concenreations, some elements of $Fe_{2}O_{3}$, CaO, MgO, $P_{2}O_{5}$, Cu, Ni, Zn and Zr showed typical trends in the secondary contramination sediments. These trends are typically shown under 100 mesh fractions. It indicates that the fraction of minus 100 mesh is the optimum size fraction for geochemical and environmental survey.

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Control of Particle Size and Luminescence Property in Zn$_2$SiO$_4$:Mn Green Phosphor (Zn$_2$SiO$_4$:Mn 녹색형광체의 입도제어 및 발광특성)

  • Seong, Bu-Yong;Jeong, Ha-Gyun;Park, Hui-Dong
    • Korean Journal of Materials Research
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    • v.11 no.8
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    • pp.636-640
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    • 2001
  • In order to improve the optical Performance of green emitting phosphor for plasma display panel (PDP) application, the wet chemical method for preparing $Zn_{2-x}$ $SiO_4$:xMn (xi=0.02. 0.08) phosphor was designed. The spherical phosphor particles were obtained and the size can be between 0.5$\mu\textrm{m}$ and 2$\mu\textrm{m}$. The formation of phosphor, which had the willemite structure, was completed at relatively low temperature of 108$0^{\circ}C$. Also, photoluminescence Properties of the phosphors prepared were investigated under vacuum ultraviolet excitation. In particular, the emission intensity of Zn$_2$SiO$_4$:0.08Mn phosphor having the 1$\mu\textrm{m}$ of particle size was higher than that of commercial phosphor by 40%. The decay time of zinc silicate powder prepared as containing 8 mole% of manganese has been measured as 7.8ms.

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Control of Particle Size and Luminescence Property in Zn$_2$SiO$_4$:Mn Green Phosphor (Zn$_2$SiO$_4$:Mn 녹색형광체의 입도제어 및 발광특성)

  • 성부용;정하균;박희동
    • Korean Journal of Materials Research
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    • v.11 no.8
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    • pp.363-363
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    • 2001
  • In order to improve the optical Performance of green emitting phosphor for plasma display panel (PDP) application, the wet chemical method for preparing $Zn_{2-x}$ $SiO_4$:xMn (xi=0.02. 0.08) phosphor was designed. The spherical phosphor particles were obtained and the size can be between 0.5$\mu\textrm{m}$ and 2$\mu\textrm{m}$. The formation of phosphor, which had the willemite structure, was completed at relatively low temperature of 108$0^{\circ}C$. Also, photoluminescence Properties of the phosphors prepared were investigated under vacuum ultraviolet excitation. In particular, the emission intensity of Zn$_2$SiO$_4$:0.08Mn phosphor having the 1$\mu\textrm{m}$ of particle size was higher than that of commercial phosphor by 40%. The decay time of zinc silicate powder prepared as containing 8 mole% of manganese has been measured as 7.8ms.

The Synthesis of Nano-sphere Titanium-oxide and Cosmetic Applications (광반사체로 사용되는 $TiO_2$ 나노구형체의 합성과 화장품으로의 적용 연구)

  • Lee, Ji Hye;Kim, Joon Woo;Kim, Ji Man;Choung, Suk-Jin
    • Applied Chemistry for Engineering
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    • v.24 no.3
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    • pp.231-238
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    • 2013
  • In this study, the $TiO_2$ nano spheres were synthesized by Sol-gel method to give an excellent UV-blocking effect and increase waste adsorption. The pH value was adjusted to obtain a superb UV-blocking effect and adsorption capacity due to the high surface area which is the characteristics of porosity. Base treated $TiO_2$ showed outstanding characteristics. The adsorption of gycerine onto the $TiO_2$ sample using TGA resulted in a high surface area of 1.16 mg/mg. This also showed a high reflectance in the UV-A region. In order to find the optimum dispersion, inorganic powder particles were maintained their sizes as 180 nm for about 6 months. The size of particles were measured using ester oil and silicon oil. Overall, the results reveal that $TiO_2$ has an excellent capability sunscreen in the UV-A region and skin waste adsorption.

A Study on Nano-emulsion for Enhanced Transdermal Delivery of Hippophae rhamnoides Leaf Extract (비타민나무 잎 추출물의 피부 흡수 증진을 위한 나노에멀젼 연구)

  • Chae, Kyo Young;Kwon, Soon Sik;Park, Soo Nam
    • Applied Chemistry for Engineering
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    • v.24 no.3
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    • pp.260-265
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    • 2013
  • In this study, nano-emulsions containing 0.01, 0.03, 0.05, and 0.10% ethyl acetate fraction of Hippophae rhamnoides (H. rhamnoides) leaf extracts were prepared. The particle size, particle size distribution and skin permeability of the nano-emulsions were evaluated for five weeks. Nano-emulsion was prepared by the sequential use of homogenizer and microfluidizer. Nano-emulsion containing the ethyl acetate fraction exhibited a monodispersed form. Nano-emulsion containing 0.03% ethyl acetate fraction was the most stable for five weeks. The in vitro skin permeation study of nano-emulsion containing 0.03% ethyl acetate fraction was carried out using Franz diffusion cell. The nano-emulsion showed a better skin permeability than that of O/W emulsion. These results indicate that the nano-emulsion containing the ethyl acetate fraction of H. rhamnoides leaf extract showed a remarkable stability and skin permeability than that of O/W emulsion.

Characteristics of Nickel Aluminate Ceramics Synthesized by Organic (PVA)-Inorganic Solution Technique (PVA 폴리머를 이용한 니켈 알루미네이트 분말의 합성 및 특성연구)

  • 이상진;김주원
    • Journal of the Korean Ceramic Society
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    • v.40 no.7
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    • pp.690-695
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    • 2003
  • Soft-solution route employing PVA(Polyvinyl Alcohol) as a polymeric carrier in a mixed metal cation solution was used for synthesis of single-phase nickel aluminate (NiA1$_2$O$_4$) powders. The PVA ensured the homogeneous distribution of metal ions in the solution and it resulted in the decrease of crystallization temperature. The synthesized powders prepared by PVA addition were soft and ball-milled easily. The ball-milled powders of about 300 nm in size were fully densified to density of 4.35 g/㎤ at 1600$^{\circ}C$ for 1 h. The Vickers hardness, flexural strength, fracture toughness and thermal expansion coefficient of the sintered nickel aluminate were 14.2 ㎬, 304 ㎫, 4.8 ㎫$.$m$\^$1/2/ and 9.8${\times}$10$\^$-6//$^{\circ}C$, respectively.

Evaluation of CPTU Cone Factor of Silty Soil with Low Plasticity Focusing on Undrained Shear Strength Characteristics (저소성 실트지반의 비배수 전단강도 특성을 고려한 CPTU 콘계수 평가)

  • Kim, Ju-Hyun
    • Journal of the Korean Geosynthetics Society
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    • v.16 no.1
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    • pp.73-83
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    • 2017
  • Laboratory and in-situ tests were conducted to evaluate the cone factors for the layers with low plasticity containing a lot of silty and sand soils from the west coast (Incheon, Hwaseong and Gunsan areas) and its applicability was evaluated based on these results. The cone factors were evaluated from 19 to 23 based on unconfined compression strengths (qu), from 13 to 13.8 based on simple CU strengths and from 11.6 to 13.1 based on field vane strengths, respectively. The unconfined compression strengths of undisturbed silty soil samples with low plasticity were considerably underestimated due to the change of in-situ residual effective stress during sampling. Half of unconfined compression strength (qu/2) based cone factors of silty soils with low plasticity fluctuated and were approximately 1.8 times higher than simple CU based values of these soils. When evaluating cone factors of these soils, it should be judged overall on the physical properties such as the grain size distribution and soil plasticity and on the fluctuation of the corrected cone resistance and the sleeve friction due to the distribution of sandseam in the ground including pore pressure parameter.

A Case Study of Combining NDC Blasting Method and Wide Space Blasting Method to Increase Blast Efficiency (NDC 및 Wide Space 혼합공법을 통한 발파효율 개선 사례연구)

  • No, Sang-Lim;Noh, Seung-Hwan;Lee, Sang-Pil;Lee, Hoon-Yeon;Lee, Tai-Ro
    • Tunnel and Underground Space
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    • v.16 no.5 s.64
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    • pp.387-393
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    • 2006
  • This paper introduces the combination of two blasting methods applied to reduce blast-vibration and increase blast efficiency. NDC (New Deck Charge) blasting method using air deck effect with separation tube made of paper was effective to reduce blast-vibration, while blast efficiency was decreased a little in the bottom of a blasthole. Wide Space blasting method has an advantage to control the fragmentation and to increase blast efficiency over conventional blasting methods. In this study new blasting method combining NDC blasting method and Wide Space blasting method was applied to the field, it was confirmed to reduce blast-vibration and increase blast efficiency. It is expected to make useful blasting method to cover the public complaints and to shorten construction time by accumulating blasting data using new method with various conditions.

Preparation of Kenyaite/epoxy Nanocomposite from Pulverization of Kenyaite (분쇄된 Kenyaite를 이용한 Kenyaite/epoxy 나노복합체 제조)

  • Joo, Eul-Rea;Jeong, Soon-Yong;Oh, Seong-Geun;Kwon, Oh-Yun
    • Applied Chemistry for Engineering
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    • v.18 no.1
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    • pp.48-53
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    • 2007
  • Pulverization characteristics of H-kenyaite in vibration mill and exfoliation property in epoxy of pulverized H-kenyaite was investigated by using XRD, SEM, TEM. and particle size analyzer. Pulverization was conducted for 0.5~5 h. The particle morphology of sample pulverized for 1 h preserved plate-shape. However, this plate-shape disappeared in the sample pulverized for 3 h. The XRD pattern of sample pulverized for 1 h showed the characteristic peak of H-kenyaite. However, the peak disappeared in samples pulverized above 3 h, indicating severe destruction of H-kenyaite structure. TEM analysis for the kenyaite/epoxy nanocomposites exhibited only gallery expansion of 3~5 nm in non-pulverized sample, but dramatical large expansion of 5~10 nm in the samples pulverized during 1 h. This results confirm that the pulverization of wide plates composed of H-kenyaite particle have largely affect on the formation of an exfoliated kenyaite-polymer nanocomposite.

Particle Behavior and Properties of Pigment Red 57:1 Synthesized in Various Reaction Conditions (다양한 반응 조건에 따른 적색안료 57:1의 입자거동 및 특성)

  • Yang, Seok Won;Kim, Jae Hwan;Kim, Do Hyun;Jin, Young Eup;Lee, Gun-Dae;Park, Seong Soo
    • Applied Chemistry for Engineering
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    • v.28 no.1
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    • pp.95-100
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    • 2017
  • In this study, various Pigment Red 57:1 samples and also their dispersant were prepared in various synthesis conditions via changing parameters such as synthesis time, pH, derivative content and synthesis temperature in order to analyze the pigment particle behaviors and their spectroscopic and physical properties. Each sample was analyzed using Fourier infrared spectroscopy, UV-Vis spectroscopy, particle size analyzer, color spectrophotometer and X-ray diffractometer and their characteristics were compared. As a result, it was possible to control the size of pigment particles by controlling the synthesis conditions.