• Environmental Engineering Research
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• 제23권4호
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• pp.364-373
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• 2018

The present study assessed the efficient removal of nutrients and Chlorophyll-a (Chl-a) by using methyl esterified sericite (MES) and pine needle extracts (PNE), a low cost and abundant green hybrid material from nature. For this purpose, the optimal conditions were investigated, such as the pH, temperature, MES and PNE ratio, and MES-PNE dose. In addition, a Microcystis aeruginosa control using MES-PNE was also analyzed with various inhibition models. The removal of the nutrient and Chl-a onto MES-PNE was optimized for over 95% removal as follows: 2-2.5 for the MES-PNE ratio, 7-8 pH and a $22-25^{\circ}C$ temperature. In this respect, approximately 1.52-2.20 g/L of MES-PNE was required to remove each 1 g of dry weight/L of Chl-a. Total phosphorus (TP) has a greater influence on the increase in Chl-a than total nitrogen (TN) according to the correlation between TN, TP and Chl-a. Moreover, the Luong model was the best model for fitting the biodegradation kinetics data from Chl-a on MES-PNE from lake water. The novel hybrid material MES-PNE was very effective at removing TN, TP and Chl-a from the lake and can be applied in the field.

• 한국분말야금학회:학술대회논문집
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• 한국분말야금학회 2003년도 international symposium on advanced powder metallurgy
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• pp.78-79
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• 2003

A functionally graded material was produced by laminating green tapes. The lamination resulted in the formation of functionally graded structure and sintering of the materials resulted of FGM. This results demonstrated a possibility of using green tapes in the processing of functionally graded materials.

• 한국세라믹학회지
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• 제53권4호
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• pp.381-385
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• 2016

Recently, white LEDs, especially, warm white LEDs have been intensively investigated due to outstanding optical properties, long term stability and low power consumption. In this study, mixed type and patterned type of remote phosphors were prepared by screen printing process employing green and red phosphor. Each type of remote phosphor exhibited distinctive photoluminescence spectrum. For example, the mixed type of remote phosphor exhibited unique spectrum, while the patterned type showed expectable spectrum depending on the concentration of phosphors. This indicates that a small amount of red phosphor dramatically reduced the green photoluminescence in the case of mixed-type remote phosphor, whereas the effect was negligible in the patterned-type remote phosphor. The possibility of undesirable chemical reaction was further investigated by using scanning electron microscopy and X-ray diffraction.

• 한국식품영양학회지
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• 제31권2호
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• pp.313-317
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• 2018

This study investigated the nutritional composition of green pepper (Capsicum annuum L. cv. DangZo). Specifically vitamin C, minerals and amino acids content in green peppe were measured. The crude ash, crude protein, and crude fat contents of green pepper were found to be 0.64, 2.10 and 1.20 g/100 g, respectively. The ascorbic acid content in green pepper was 99.34 mg/100 g. The K content was found to be the highest with regard to mineral. This was followed by P, Mg, Na, Ca, Zn, Cu, Mn which means green pepper is an alkali material. The K, P, Mg, Na, Ca, Zn, Cu, Mn contents of green pepper found to be 980, 68.33, 60, 34.14, 30.88, 5.87, 5.25 and 3.07 mg/100 g respectively. The total amino acid content ranged from 7.0 to 1,625.3 mg/100 g, respectively. With regard to amino acid contents, arginine and citrulline were found to be abundant. From the results, green pepper could be suggested as beneficial for food processing.

• 한국분말야금학회:학술대회논문집
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• 한국분말야금학회 2006년도 Extended Abstracts of 2006 POWDER METALLURGY World Congress Part 1
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• pp.295-296
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• 2006

High hardness of P/M parts can be obtained in the cooling section of the sintering furnace by using sinter hardenable materials, thus the post-sintering heat treatment can be eliminated. However, the sinter hardened materials would have difficulties in secondary machining if it is required, which will limit the applications of sinter hardenable materials in the machined parts. Recent development in warm compaction technology can enable us not only to achieve the high green density up to $7.4\;g/cm^3$, but also the high green strength which is needed for green machining. Therefore by using warm compaction technology, the green machining can be applied to sinter hardenable materials for the high density, strength and hardness P/M parts. In the present study, a pre-alloyed steel powder, ATOMET4601, was used by mixing with 2.0% copper, 1.0% nickel, 0.9% graphite and a proprietary lubricant using a binder treatment process - FLOMET. The specimens were compacted and green machined with different machining parameters. The machined surface finish and part integrity were evaluated in selecting the optimal conditions for green machining. The possibility of applying the green machining to the high-density structural parts was explored.

• Bulletin of the Korean Chemical Society
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• 제34권7호
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• pp.2041-2043
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• 2013

A layered perovskite of Dion-Jacobson phase, $RbLaTa_2O_7$, was successfully exfoliated into colloidal suspension via successive ion-exchange and intercalation reaction. The pristine perovskite $RbLaTa_2O_7$ was synthesized by conventional solid-state reaction, and then, it was ion-exchanged with hydrochloric acid to obtain a protonic form of perovskite. The resulting proton-exchanged perovskite was reacted with ethylamine to increase interlayer spaces for further intercalation reaction. Finally, the ethylamine-intercalated form was exfoliated into nanosheets via an intercalation of bulky organic cations (tetrabutylammonium). According to X-ray diffraction (XRD) analysis, the TBA-intercalated form showed remarkably increased interlayer spacing (${\Delta}d$ = 1.67 nm) in comparison with that of the pristine material. Transmission electron microscopic image of exfoliated perovskite clearly revealed that the present exfoliated perovskite were composed of very thin layers. This exfoliated perovskite nanosheets could be applicable as building blocks for fabricating functional nanocomposites.

• 한국세라믹학회지
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• 제47권3호
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• pp.249-255
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• 2010

To investigate optical properties of (V, Pr)-doped $ZrSiO_4$ green pigments, samples were prepared by the ceramic method using NaF and NaCl as mineralizers. They were characterized by X-ray diffraction, UV-Vis spectroscopy and Raman spectroscopy. The changes of color in the samples during heating and effect of mineralizers were studied in terms of valence of the vanadium and praseodymium in the zircon matrix. (V, Pr)-doped $ZrSiO_4$ pigments give rise to green coloration in $800^{\circ}C$. The oxidation state of V and Pr ions of pigments in the glazed samples were confirmed by UV-Vis absorption spectra. This absorption spectra showed three typical bands of trivalent Pr at the 445, 480~490, 592 nm due to f-f transitions and two broad bands of 302~380, 400~500 nm due to f-d transitions of tetravalent Pr. According to the increasing amounts of $Pr_6O_{11}$, the two broad bands showed decreasing intensity at 290, 640 nm due to d-d transitions of tetravalent V.

• 한국주조공학회지
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• 제30권3호
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• pp.115-120
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• 2010

Recently, an advanced raw material supplying system in diecasting industry that molten metal produced by the raw material supplier can be directly delivered to the diecasting shops was proposed. It was known to have advantages of reducing melting process cost and improving working environment. However, for its successful mass production, the development of high insulation ladle is inevitable. In this study, the optimal mixing ratio of $SiO_2-Al_2O_3$ was investigated and the high insulation ladle with computer simulation result was built in a prototype and evaluated. The prototype which has refractory wall of $SiO_233%-Al_2O_3$ 35%-CaO 33% showed high insulation sufficient for carrying the Al molten metal for 138 minutes. Gas quantity result and SEM-EDS analysis on the melt poured in the ladle also showed extremely low level of 0.028 cc / 100 g and no penetration of Al molten metal into the refractory wall, satisfying the requirements for mass production.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2013년도 제44회 동계 정기학술대회 초록집
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• pp.546-546
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• 2013

Zinc silicate ($Zn_2SiO_4$) has been identified as a suitable host material for a wide variety of luminescent activators, such as transition metal and rare earth elements. In particular, manganese-activated $Zn_2SiO_4$ exhibits highly efficient photoluminescenceand cathodoluminescence, which allows this material to be used in fluorescent lamps and display applications. In this study, we investigated the green and yellow luminescence from Mn-doped $Zn_2SiO_4$ thin films that were synthesized using radio frequency magnetron sputtering followed by annealing at $600{\sim}1,200^{\circ}C$ The refractive index of the $Zn_2SiO_4$: Mn films showed normal dispersion behavior. It was found that the $Zn_2SiO_4$: Mn films annealed at $800^{\circ}C$ ossessed a mixture of alpha and beta phases. The obtained photoluminescence spectrum consisted of two emission bands centered at 525 nm in the green range and 574 nm in the yellow range. The green luminescence originates from the divalent Mn ions in alpha phase of $Zn_2SiO_4$, while the yellow luminescence comes from the divalent Mn ions in beta phase. The films annealed at and above $900^{\circ}C$ xhibited only the alpha phase. The broad PL excitation band was observed ranging from 220 to 300 nm with a maximum at around 243 nm.

• 한국전기전자재료학회논문지
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• 제28권12호
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• pp.781-786
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• 2015

It is necessary for ferrite sheets to be fabricated with high packing density for excellent electrical properties and high strength. In this study, the relationship between the warpage and the packing density of ferrite green sheet, was investigated with amount variation of organic additives. With 0.4 wt% of dispersant, the packing density was about 48% and warpage appeared 0.5~1.3 mm high. With 1.4 wt% of dispersant, the packing density increased up to 57% and warpage appeared 0.8~2.1 mm high. With high packing density, warpage appeared along the edges of specimen, while with low packing density, deformation appeared over whole specimen inhomogeneously. It is thought that inhomogeneous deformation after sintering came from the inhomogeneity in green sheet prepared with badly dispersed slurry. With good homogeneity in green sheet from well-dispersed slurry, isotropic shrinkage is thought to have occurred along the distance from center to edges of specimen during sintering.