• Korean Chemical Engineering Research
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• v.58 no.2
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• pp.230-234
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• 2020

A system that uses deep-learning techniques to predict properties from molecular structures has been developed to apply to chemical, biological and material studies. Based on the database where molecular structure and property information are accumulated, a deep-learning model looking for the relationship between the structure and the property can eventually provide a property prediction for the new molecular structure. In addition, experiments on the actual properties of the selected molecular structure will be carried out in parallel to carry out continuous verification and model updates. This allows for the screening of high-quality molecular structures from large quantities of molecular structures within a short period of time, and increases the efficiency and success rate of research. In this paper, we would like to introduce the overall composition of the materiality prediction system using deep-learning and the cases applied in the actual excavation of new structures in LG Chem.

• Korean Chemical Engineering Research
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• v.50 no.4
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• pp.604-609
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• 2012

Properties of fucoidan used for functional cosmetic ingredients and the effect of fucoidan molecular weight on the cosmetic functions were studied. Fucoidan was extracted from Undaria pinnatifida sporophylls and molecular weight (35~160 kDa) of fucoidan was controlled by contact glow discharge electrolysis (CGDE). To test possibility of fucoidan as a cosmetics material, tyrosinase inhibition property, water-holding property, elastase activity inhibition property and DPPH free radical scavenging property were measured. Water-holding property of fucoidan was higher than that of hyaruronic acid, which is known as the one of the best water-holding material. The water-holding strength of fucoidan slightly increase as molecular weight of fucoidan decrease. Elastase activity inhibition (anti wrinkle effect) of fucoidan was higher than that of adenosine using standard material for anti wrinkle test. Optimum molecular weight of fucoidan to obtain highest tyrosin inhibition effect, elastase inhibition effect and radical scavenger effect is 100 kDa.

• KSBB Journal
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• v.31 no.4
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• pp.291-299
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• 2016

In this study, Indomethacin, the poorly water soluble drug, was selected and prepared dispersing oral disintegrating films according to the molecular weight of polyethylene glycol (PEG) which are sort of dispersing agents. Also the molecular weight and content of PEG were evaluated effect on the degree of dispersion, physical property and dissolution when making oral dispersing film containing indomethacin to find appropriate condition and suggested guidelines of making oral dispersing film. The appropriate dispersing ratio of the amount of surfactants and dispersing agent were 1% and 4%, also the stability dropped in the PEG molecular weight of 4000 or more. Drying time of oral dispersing film was $90^{\circ}C$ for 10 minutes to 12 minutes that dispersing film's property about flexibility, detachability were very good. The oral dispersion film's content used PEG 400 was $98.6{\pm}0.5%$ and the most uniform. As the molecular weight of PEG increased, dissolution time also increased. On the basis of evaluation parameter, PEG with 400~600 of molecular weight was selected as good dispersing agent in oral dispersing film. Therefore, it can be suggested guideline of preparation application study in oral dispersing film.

• Tribology and Lubricants
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• v.17 no.5
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• pp.386-390
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• 2001

Monolayers such as self-assembled monolayer (SAM) have received considerable attention to reduce stiction and friction in micro-devices and microelectromechanical systems (MEMS). Various organic molecular films were investigated to obtain better understanding of their tribological behaviors and adhesion property. The organic molecular films studied in this work are: epoxysilane SAMs, octadecyltricholosilane (OST), multi-layers composed of epoxysilane SAMs, poly[styrene-b-(ethylene-co-butylene)-b-styrene](SEBS) and compound of epoxy resin and poly (paraphenylene)(EP/PPP). The pull-off forces of these films were also obtained from force-distance curves measured in static mode of operation of atomic force microscope(AFM). Tribological tests were conducted with a ball-on-flat reciprocating friction tester. The OST showed the lowest pull-off force, indicating its low adhesion property. It was revealed that, the OST, EP/PPP and the multi-layer of epoxysilane SAMs, SEBS and EP/PPP exhibited good tribological properties at the lower load (0.3 N) whereas the OST showed best performance at the higher load (1.8 N).

• Bulletin of the Korean Chemical Society
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• v.25 no.2
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• pp.182-184
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• 2004

Fine $La_{2/3}Ca_{1/3}MnO_3$ nanocrystalline powders have been successfully prepared by modified citrate pyrolysis process. The obtained LCMO nanoscale grains have a mean particle size of about 30 nm under optimal treatment conditions. The particle size can be controlled by adjusting processing parameters, such as treatment temperature and calcination time. X-ray diffraction, SEM and magnetoresistance effect were employed to study the crystal structure, morphology and magnetic property of these nanosized powders. A novel MR effect (MR > 45% (0 K < T < 340 K)) at room temperature has been found.

• Journal of environmental and Sanitary engineering
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• v.20 no.2 s.56
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• pp.33-38
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• 2005

Chitosan is a dietary fiber because of a linear polysaccharide composed of $\beta-(1{\rightarrow}4)$-linked 2-amino-2-deoxy-D-glucopyranose. In this study, control release system of vitamin C has been estimated in chitosan molecular network as a vitamin C carrier of controlled release. The amount of released vitamin C were decreased in higher amount of chitosan concentration. Especially, vitamin C were slowly released from chitosan solution in dialysis membrane when compared with vitamin C solution alone in dialysis membrane. These result assumed that chitosan driving force is dependent on chitosan molecular weight and cationic property of amino group with anionic property of vitamin C.

• Journal of the Korean Applied Science and Technology
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• v.22 no.1
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• pp.77-83
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• 2005

The influence of fluorescence, scattering, and absorbance in turbid material by light scattering was interpreted by the scattered fluorescence intensity and wavelength. The effect of optical property in scattering media was investigated. It is very important to study the charge coupled device(CCD) in spectrometry because we can use the molecular energy level, molecular structure, absorption or emission, intermolecular reaction, weakly bound molecular energy, photochemistry, fluorescence and photodynamic therapy. CCD is very essential to study the molecular structure and medical engineering combined laser spectroscopy in the modem physical and chemistry. Accordingly, this study has designed and manufactured the electromagnetic spectrometry with CCD, and has analyzed the hematoporphyrin derivative.

• Proceedings of the Korean Society of Tribologists and Lubrication Engineers Conference
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• 2001.06a
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• pp.49-54
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• 2001

Monolayers such as self-assembled monolayer (SAM) have received considerable attention to reduce stiction and friction in micro-devices and microelectromechanical systems (MEMS). Various organic molecular films were investigated to obtain better understanding of their tribological behaviors and adhesion property. The organic molecular films studied in this work are: epoxysilane SAMs, octadecyltricholosilane (OST), multi-layers composed of epoxysilane SAMs, poly〔styrene-b-(ethylene-co-butylene)-b-styrene〕(SEBS) and compound of epoxy resin and poly (paraphenylene) (EP/PPP). The pull-off forces of these films were also obtained from force-distance curves measured in static mode of operation of atomic force microscope (AFM). Tribological tests were conducted with a ball-on-flat reciprocating friction tester. The OST showed the lowest pull-off force, indicating its low adhesion property. It was revealed that, the OST, EP/PPP and the multi-layer of epoxysilane SAMs, SEBS and EP/PPP exhibited good tribological properties at the lower load (0.3 N) whereas the OST showed best performance at the higher load (1.8 N).

• Bulletin of the Korean Chemical Society
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• v.34 no.1
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• pp.283-286
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• 2013

• Magazine of the Korea Concrete Institute
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• v.3 no.1
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• pp.71-78
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• 1991

Moleclar size distribution of three AC-20 asphalt cements were observed using high pressure - gel permeation chromatograph (HP-GPC). Bituminous concrete specimens were made using the asphalt cements and one aggre¬gate in laboratory to measure mechanical properties, tensile strength CIS) and resilient modulusCM,J. in dry and wet conditons. Results of mechanical property tests and profile of molecular size distribution of asphalt cements were analyzed to evaluate the relatonship of mechanical property with chromatogram. Regression analy¬sis showed a strong correlation between a mechanical property and sliced percent areas of chromatogram. Mathematical prediction models were developed based on the regression analysis. It was shown that characteris¬tics of asphalt cement chromatogram could be successfully used for estimation of selected mechanical property of asphalt concrete .