• Korean Journal of Pharmacognosy
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• v.28 no.4
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• pp.257-263
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• 1997

Berberis amurensis Ruprecht(Berberidaceae) is a medicinal plant indigenous to the middle and northern part of Korean peninsula. The woody parts of this plant have been used for the ocular, peptic and intestinal disorders. The stems of this plants were extracted with MeOH and the MeOH extract was partitioned between organic phases and water layer, successively to fractionated quarternary alkaloids. The acetone-soluble part of guarternary alkaloidal fraction had antibacterial activities and it contained four protoberberine alkaloids such as palmatine(I), Berberine(II), Jatrorrhizine(III) and coptisine(IV), and one aporphine alkaloid, magnoflorine(V). Although the isolations of the compounds I, II, IIII, IV and V from different sources were reported, this is the first report that Berberis amurensis contained the compounds. When the contents of compound I(palmatine) and II(berberine) were quantified and compared with those of other plant parts, cortex contained higher palmatine and berberine than any other part of the plant.

• Journal of the Korean institute of surface engineering
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• v.32 no.3
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• pp.265-275
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• 1999

Titanium nitride and related overlayers produced by arc ion plating (AIP) are applied as commercial coatings in world-wide scale since the middle of 80s. Due to the achievements of low temperature deposition (LTD), they begin now to be used as wear and corrosion-resistant coatings for machine parts, besides applications on cemented carbide and high speed steel cutting tools. On the other side, TiN can be now applied successfully to brass, Al-alloy, ZnAl alloy articles as decorative coating through LTD. Various nitrides, carbonitrides, borides and other refractory compounds, such as (Ti, Al)N, TiCN, CrN, are used as the coatings for special heavy-duty working conditions instead of TiN since 90s. More and more multilayer coatings are applied now substituting single layer ones. Duplex processes are under development.

• Proceedings of the Korean Institute of Surface Engineering Conference
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• 2003.05a
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• pp.31-32
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• 2003

In the Present study, the effect of galvannealing conditions on the phase distribution of the Zn-Fe intermetallic phases in the coating layer of the galvannealed steel sheets(GA) was investigated in an interstitial free steel and two kinds of high strength steels. The composition profiles of the coating layers were analyzed using AA and EDS analysis, and the distribution of the intermetallic phases was examined with the aids of X-ray diffraction. On the basis of the pole figure and OIM analyses, it was clarified that the preferred orientation of the $\zeta$ phase depended on the development of the $\gamma$-fibre texture in the substrate.

• Journal of the Korean institute of surface engineering
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• v.32 no.1
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• pp.31-42
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• 1999

The effect was investigated that aluminium in the zinc bath has on the coating adhesion of Hot-rolled Galvanized Iron(HGI) manufactured without pickling process. It is thought that the coating adhesion of HGI manufactured without pickling process is good due to the fact that increasing aluminium content in the zinc bath makes zinc and aluminium diffuse to the cracks or pores in the scale formed through the reduction heat treatment, and Fe-Zn-Al compound with good ductility is formed in the scale layer and plays a role of anchor between zinc coating and substrate. It is possible that HGI with the good coating adhesion was produced without pickling treatment in the zinc bath with more that 3wt% of Al content even at the $550^{\circ}C$ of conventional reduction heating temperature. In creasing the temperature of heating section and aluminium content in the zinc bath prevents the Zn-Fe alloy. The corrosion resistance of HGI manufactured without pickling process is excellent because of the mixed reaction of zinc sacrifice and aluminium passivity film.

• Journal of the Korean Applied Science and Technology
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• v.15 no.1
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• pp.99-108
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• 1998

Novel type surfactants containing two long-chain hydrophobic alkyl groups and two hydrophilic sulfonate groups were successfully synthesized by reactions of ethylene glycol diglycidyl ether with long-chain fatty alcohols, after then by reactions with 1,3-propane sultone and sodium hydride under THF solvent. All these compounds, so called Gemini surfactants, were purified by thin layer chromatography and column chromatography. Their structures were identified by FT-IR and $^{1}H$-NMR.

• Journal of the Semiconductor & Display Technology
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• v.18 no.4
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• pp.120-123
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• 2019

The effect of surface plasmon on ZTO thin films was investigated. The phenomenon of depletion occurring in the interface of the ZTO thin film created a potential barrier and the dielectric layer of the depletion formed a non-mass particle called plasmon. ZTO thin film represents n-type semiconductor features, and surface current by plasma has been able to obtain the effect of improving electrical efficiency as a result of high current at positive voltage and low current at negative voltage. It can be seen that the reduction of electric charge due to recombination of electronic hole pairs by heat treatment of compound semiconductors induces higher surface current in semiconductor devices.

• Journal of Korea Society of Digital Industry and Information Management
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• v.15 no.2
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• pp.19-28
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• 2019

The purpose of this study is to examine the trends on machine learning and deep learning research in the published journals from the Web of Science Database. To achieve the study purpose, we used the abstracts of 20,664 articles published between 1990 and 2017, which include the word 'machine learning', 'deep learning', and 'artificial neural network' in their titles. Twenty major research topics were identified from topic modeling analysis and they were inclusive of classification accuracy, machine learning, optimization problem, time series model, temperature flow, engine variable, neuron layer, spectrum sample, image feature, strength property, extreme machine learning, control system, energy power, cancer patient, descriptor compound, fault diagnosis, soil map, concentration removal, protein gene, and job problem. The analysis of the time-series linear regression showed that all identified topics in machine learning research were 'hot' ones.

• Journal of the Semiconductor & Display Technology
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• v.17 no.2
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• pp.12-15
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• 2018

InSb (III-V compound semiconductor) is used for photodiode to detect the mid-wavelength infrared radiation. Generally the quantum efficiency of InSb IR FPAs(Focal Plane Arrays) is known to be determined by thickness of InSb and transmittance of anti-reflection coating layer. In this study, we confirmed that the C-V characteristics of detector array affects the quantum efficiency of the InSb IR FPAs. We fabricated the IR FPAs with various $V_{fb}$(flat band voltage) values and confirmed the tendency between the $V_{fb}$ value and quantum efficiency of the IR FPAs.

• Proceedings of the PSK Conference
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• 2002.10a
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• pp.375.3-375.3
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• 2002

In continuing search for BChE-inhibitory compounds from Korean marine algae. we found a highly potent inhibitory activity in the methanolic extract of Sargassum species. After partition of the MeOH extract between $CHCl_3$ and 30% MeOH. the former layer was subjected to a series of ODS flash chromatography. silica column chromatography. and preparative TLC to afford three compounds (1-3). Detailed structural elucidation of them is in progress. Compound 1 showed potent BChE-inhibitory activity with $IC_{50}$ values of 11 ng/mL. (omitted)

• Proceedings of the PSK Conference
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• 2003.10b
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• pp.190.2-190.2
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• 2003

In the course of search for various bioactive compounds from marine algae, we found strong antioxidant activity of the methanolic extract of the brown alga G. elliptica. Chromatographic purification [ODS flash, gel-filtration on Sephadex LH-20, HPLC] of the BuOH layer of the methanolic extract afforded two known polyphenolic compounds, 6,6'-bieckol (1) and dieckol (2). Compound 1 showed acetylcholinesterase (AChE) and butyrylcholinesterase (BuChE) inhibitory activities, free radical scavenging activity on DPPH (1,1-diphenyl-2-picryl-hydazyl) with IC$\_$50/ values of 91.2, 45.6 and 15.5 $\mu\textrm{g}$/$m\ell$, respectively. (omitted)