• Proceedings of the Korean Society of Soil and Groundwater Environment Conference
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• 2006.04a
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• pp.16-19
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• 2006

Humin is the insoluble fraction of humic materials and play an important roles in the irreversible sorption of hydrophobic organic contaminants onto soil particles. However, there have been limited knowledge about the sorption and chemical properties of humin due to the difficulties in its separation from the inorganic matrix(mainly clays and oxides). In this study, do-ashed humin was isolated from a soil sample after removing free lipid and alkali-soluble humic fractions followed by dissolution of mineral matrix with 2% HF, and characterized by elemental analysis, C-13 NMR spectroscopic method. Sorption behavior of 1-naphthol with humin was also investigated from aqueous solution. C-13 NMR spectra indicate that humin molecules are mainly made up of aliphatic carbon including carbohydrate, methylene chain etc.. Sorption intensity for 1-naphthol was increased as organic carbon content of humin increased and log Koc values for the 1-naphthol sorption were determined to be ${\sim}3.12$

• Proceedings of the KAIS Fall Conference
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• 2008.11a
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• pp.459-462
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• 2008

본 논문에서는 $10K_2O$-30CaO-$60P_2O_5$ mol%를 기본조성으로 하여 Fe, Cu, Zn의 미량성분을 첨가하여 유리를 제조하고 용출 특성을 평가 하였다. 제조된 유리는 미량성분의 첨가량에 따라 유리의 투명도가 변하는 것이 관찰되었다. 용출특성은 측정 4시간 뒤 pH값 증가되는 것으로 16시간 후 pH가 증가하는 것으로 관찰되었다. 여기서 pH의 증가는 염기성산화물이 용출되는 것으로, 감소는 $P_2O_5$구조인 망목형성구조가 붕괴되어지면서 산성이온이 용출되어지는 것으로 판단되어진다. ICP관찰시에는 함량이 증가하면서 K, Ca, P이온의 용출량이 감소되었고, Zn, Cu, Fe이온의 용출량이 증가하는 경향이 관찰되었다.

• Proceedings of the Korean Vacuum Society Conference
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• 2011.08a
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• pp.111-111
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• 2011

Arrangement of individual atoms and molecules with atomic precision and understanding the resulting properties at the molecular level are ultimate goals of chemistry, biology, and materials science. For the past three decades, scanning probe microscopy has made strides towards these goals through the direct observation of individual atoms and molecules, enabling the discovery of new and unexpected phenomena. This talk will discuss the origin of forces governing motion of small organic molecules and their extended self-assembly into two-dimensional surface structures by direct observation of individual molecules using scanning tunneling microscopy (STM). In addition, atomic force microscopy (AFM) is utilized for the investigation of fundamental mechanisms of bone mineral dissolution by examining atomically well characterized simulated bone minerals under aqueous solution environments.

• Journal of Pharmaceutical Investigation
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• v.14 no.4
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• pp.170-177
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• 1984

For the purpose of improving the fluidity of enteric-coated powders, various mineral silicates were added during spray drying process. Aqueous slurries of cimetidine, mineral silicates containing CMEC (carboxy methyl ethyl cellulose) were spray dried using a centrifugal wheel atomizer. The finely agglomerated powders obtained by this process were flowing as opposed to the original powders. The effect of four mineral silicates (colloidal silica, talc, bentonite, and kaolin) on the micromeritic properties and dissolution profiles of spray dried agglomerates were examined.

• Archives of Pharmacal Research
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• v.28 no.5
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• pp.612-618
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• 2005

A mucoadhesive microsphere was prepared by an interpolymer complexation and solvent evaporation method, using chitosan and poly(acrylic acid) (PAA), to prolong the gastric resid ence time of the delivery system. The Fourier transform infrared results showed that microspheres were formed by an electrostatic interaction between the carboxyl groups of the PAA and the amine groups of the chitosan. X-ray diffraction and differential scanning calorimetry analysis showed that the enrofloxacin in the chitosan-PAA microsphere was molecularly dispersed in an amorphous state. Scanning electron microscopy of the surface and the quantity of mucin attached to the microspheres indicated that chitosan-PAA microspheres had a higher affinity for mucin than those of chitosan alone. The swelling and dissolution of the chitosan-PAA microspheres were found to be dependent on the pH of the medium. The rate of enrofloxacin released from the chitosan-PAA microspheres was slower at higher pH; therefore, based on their mucoadhesive properties and morphology, the chitosan-PAA microspheres can be used as a mucoadhesive oral drug delivery system.

• Proceedings of the Korea Concrete Institute Conference
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• 2005.05b
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• pp.489-492
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• 2005

The Purpose of this study is to develope the method for early recovery of the biodiversity in the oligotrophical costal area. The result of this study, the dissolution ratio is superior in the case which the cement coating thickness of the granular fertilizer is below 1mm. From the failure-side it is judged with the fact that appropriate to use the separate charging method and vibration compaction method. For the cases of the mixing ratio of cement coating granular fertilizer, there was not any clear tendency for the change of the strength up to 20$\%$ of the mixing ratio. However, at the 30$\%$ mixing ratio, decrease of the strength was noticed. So it can be concluded that the stability can be achieved in the range of 20$\%$ and below.

• Corrosion Science and Technology
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• v.6 no.2
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• pp.56-61
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• 2007

Carbide dissolution during heating processes can change chemical composition of martensitic stainless steel in its austenitic phase. Although the austenitizing treatments were carried out at a homogeneous austenite region, the amount of carbon atom in the matrix differs. Increase in the amount of carbon contents in the matrix resulted in decreasing MS temperature, which consequently causes the volume fraction of the retained austenite to increase. This study reveals the effects of the austenitizing treatment on the properties of Fe - 0.3C - 14Cr - 3Mo martensitic stainless steel change with different austenitizing temperatures.

• International Journal of Naval Architecture and Ocean Engineering
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• v.9 no.2
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• pp.199-208
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• 2017

We perform an experiment on lacquer formation with simple test device. The anti-lacquer is one of important issues to increase durability, and to improve performance in the engines because the lacquer formation cause sticking of fuel injection pump, scuffing of cylinder liners, and increase of lubricant oil consumption in the marine diesel engines. We suggest this simple test in order to save enormous experimental cost in marine diesel engines, and in order to have ease in performing the various tests. The influences of the Base Number (BN) of lubricant oils and the sulfur content of fuel oils in the formation of lacquer are investigated. In order to investigate physical and chemical properties of lacquer, we perform a variety of tests such as, visual inspection, EDS. In addition, we investigate adhesion of lacquer by pull-off test quantitatively, and perform dissolution test with dilute sulfuric acid.

• YAKHAK HOEJI
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• v.30 no.3
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• pp.128-138
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• 1986

Three newly synthesized alkanol esters of d-2-(6-methoxy-2-naphthyl) propionic acid, NAPROXEN were examined for physicochemical properties and biopharmaceutical characteristics. These esters were very stable in solid state, but more than 90% of these esters were hydrolysed to the parent, naproxen in rabbit's liver hornogenates. They showed higher dissolution rate in the artificial gastric and intestinal juice, and significantly greater partition coefficient in n-octanol, when compared with naproxen. The absorption rate constants of these esters were increased, while the elimination rate constants were decreased, comparing with naproxen. The ulcerogenic doses on gastric and intestinal mucosa were increased remarkably, and the antiinflammatory dose against carrageenininduced edema on rat hind paw was decreased markedly in these esters, and thus the safety indexes of these esters were higher than that of naproxen.

• Proceedings of the Korea Concrete Institute Conference
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• 2006.11a
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• pp.893-896
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• 2006

This study examined plant adhesion characteristics of the porous concrete that used specially treated granular fertilizer for field application, which was used for the restoration of the marine ecosystem. The results of the experiment showed that nutrient eruption amount, the destruction and dissolution ratio tended to decrease when the coating thickness was increased. The void ratio and compressive strength tended to decrease when the specially treated granular fertilizer mixing ratio was increased. According to these results, the appropriate thickness of coating for cement coated granular fertilizer was 1.0mm. The adhesion ability of marine plant to porous concrete was superior when the cement coated granular fertilizer was mixed. Therefore, the appropriate cement coated granular fertilizer mixing ratio of 20% with a coating thickness of 1.0mm is thought to be a factor when considering the strength of the porous concrete for marine ecosystem restoration and the adhesion characteristics of marine plant.