• Bulletin of the Korean Chemical Society
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• v.30 no.7
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• pp.1485-1488
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• 2009

A facile, seed-mediated preparation method of trimetallic Au@Pb@Pt core-shell nanoparticles is developed. Au nanoparticles are the template seeds onto which sequentially reduced Pb and Pt are deposited. The trimetallic core-shell structure is confirmed by UV-Vis spectroscopy, TEM and EDS analysis, and cyclic voltammetry. The trimetallic Au@Pb@Pt core-shell nanoparticles show high electrocatalytic activity for formic acid and methanol electrooxidation.

• Korean Journal of Medicinal Crop Science
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• v.19 no.5
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• pp.368-372
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• 2011

In this study, we investigated on antioxidative activity and nitric oxide production inhibitory activity of various solvent extracts of Lespedeza bicolor. The total polyphenol content of the methanol extract was 192.6 mg/g and flavonoid content of the acetone extract was 40.6 mg/g, as the highest content. In DPPH radical scavenging ability, $SC_{50}$ values of the ethanol and methanol extract were exhibited $0.69mg/m{\ell}$ and $0.89mg/m{\ell}$, respectively. However, in nitric oxide(NO) scavenging ability, $SC_{50}$ values of the acetone was exhibited $0.72mg/m{\ell}$ as the highest activity. Moreover, the acetone extract showed strong NO production inhibitory effect in lipopolysaccharide(LPS)-stimulated Raw 264.7 cell. In the cytotoxicity measurement by MTT assay, the extracts were exhibited Raw 264.7 cell viabilities of 92.57~129.04% as nontoxic result in concentration of $65{\sim}650{\mu}g/m{\ell}$. As a result, the acetone extract of L. bicolor could be applicable to functional materials for anti-inflammatory related fields.

• The Korean Journal of Food And Nutrition
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• v.34 no.4
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• pp.398-406
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• 2021

This study investigated on the nutritional components and physiological activity of four wild vegetables namely Salvia plebeia R. Br., Angelica acutiloba, Gynura procumbens and Saururus chinensis Baill for the development of representative wild vegetables in Chungbuk. Salvia plebeia possessed the highest radical scavenging activity and beta-carotene, but exhibited the lowest α-glucosidase inhibitory activity compared to the other three vegetables. Angelica acutiloba showed high crude protein content and α-glucosidase inhibitory activity, but contained low total polyphenol content, radical scavenging ability and beta-carotene compared to the other three vegetables. Gynura procumbens showed high mineral content, beta-carotene, vitamin K1 content and α-glucosidase inhibitory activity, but showed the lowest total polyphenol content and radical scavenging ability compared to the other three vegetables. Saururus chinensis showed high crude fiber content and total polyphenol content, but contained the lowest mineral and vitamin K1 content. To conclude, it is suggested to use Salvia plebeia or Saururus chinensis as antioxidant food materials and Angelica acutiloba and Gynura procumbens as food materials and sources of α-glucosidase inhibitors. In particular, it is believed that Saururus chinensis, which possessed high content of crude fiber, is suitable for low-calorie food materials such as diet products.

• Preventive Nutrition and Food Science
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• v.7 no.1
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• pp.18-21
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• 2002

The extract of Ginkgo biloba leaves was measured for inhibitory activity against xanthine oxidase. Aceton extract of G. biloba leaves showed strong inhibitory activity. Inhibitory activities of the fractionated extract were in the order of water > ethyl acetate fractions. Two fractions exhibiting strong inhibitory activities ware further purified via repeated silica gel, Amberlite IRN-78, Polyclar AT, and Sephadex LH-20 column chromatographies. Active components were isolated and identified through $^1$H-NMR and $^{13}$ C-NMR. The compounds were characterized as kaempferol 3-Ο-$\alpha$-(6$^{"′}$-p-coumaroylglucosyl-$\beta$-1,4-rhamnoside), and quercertin 3-Ο-$\alpha$-(6$^{′}$-p-coumaroylglucosyl-$\beta$-1,4-rhamnoside).

• Journal of Industrial and Engineering Chemistry
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• v.68
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• pp.380-386
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• 2018

A sustainable method was developed for the upgrade of biomass derived vanillin (a typical model compound of lignin) into the potential liquid biofuels over a layered double hydroxide supported Pd catalyst (abbreviated as CoAl-LDH/Pd). The CoAl-LDH/Pd catalyst showed high catalytic activity towards the hydrodeoxygenation of vanillin into 2-methoxy-4-methylphenol (MMP) under mild conditions in aqueous media. High MMP yield up to 86% was produced at $120^{\circ}C$ after 4 h. Kinetic studies revealed that the rate-determining step for the hydrodeoxygenation of vanillin was the hydrogenolysis of vanillyl alcohol. More importantly, the CoAl-LDH/Pd catalyst was highly stable without the loss of activity.

• Hwankyungkyoyuk
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• v.7 no.1
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• pp.46-87
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• 1994

Our country has been consuming a huge amount of energy in the course of industrialization and its demand is expected to increase enormously in the future. However, the deposits of energy resources are so limited that the settlement of energy problem comes up the essential subject. To solve the energy problem, it is requested that new resources to gain energy stably should be developed and also energy should be economized and used effectively. The effective use of energy and an the wisdom of economy in energy are requested to everybody and these things should be habitualized from very young age through education. Nevertheless, almost every school in our country hasn’t been concerned about energy education. Even though they have a concern, they are very short of the energy education materials and the quality of the materials is not so good. Therefore it is very meaningful to the settlement of energy problem of the country to make the students who will lead our country to make the students who will lead our country in the future realize the seriousness of energy problem and to provide them the necessary knowledge and methods to solve this problem so that they practice those things in everyday life. Having these necessities, this research, supported by The Korea Energy Management Corporation(KEMCO), was performed for 8 months from April 17, 1994 to December 17, 1994. Many peoples participated in this study such as 30 staffs of researchers and authors, 5 staffs of photographers and illustrators, and 3 VCR program producers developing an energy education material set for middle school students that includes a printed material for student, a diskette for computer simulation, a teacher's guidebook, VCR material and its guidebook. The following main development direction was established : First, the material for student should be consisted of units that let students know the seriousness of energy problem. Second, the focus should be put on the necessary method and practice to economize energy actually in real life based on the basic knowledge learned in elementary school. Third, material for student should be consisted of modules to be student activity-oriented teaching-learning rather than lecture-oriented one. The activity, to maximize student's interests, should be presented in various forms such as experiments, investigation, play, data interpretation, computer simulation, visits, expression and appreciation, etc. To develop the energy education materials for middle school students, a research plan was made first. After literature review about domestic and foreign energy education materials, several research trips home and abroad, and discussion meetings, the basic theory of energy education such as the principle, objective, contents, teaching-learning method, and evaluation method was established. Material for student was developed through the following procedures : The activities in the existing energy education materials were analysed and were divided into four categories related to energy using places of home, school, community, and country, and which were again divided into three categories related to time of past, present, and future, Considering these division, nine modules which are structure units of material for student were chosen, Each module comprises 2-4 activities. Totally 31 activities were designed in this way. The syllabi were made out for each activity and writing was asked for to experts related to each activity after several discussions and revision. To complement the draft, another several discussions and revision were also made on it and then pictures and illustrations were asked for. All these procedures complete the material for student, titled ; Energy Inquiry of Middle School Students', which totals 129 pages and is all in color. As the manuscript of material for student was fixed, writing for teacher's guidebook was asked for to the same writers. The draft of teacher's guidebook was also complemented through the several concentrated works and discussions. Teacher's guidebook focused on the teaching-learning principle and methods of energy education and on the concrete instruction cases for effective instruction of material for student. It is organized with two parts : the one is 'general outline' which introduces theoretical contents and the other is 'details' which are practically helpful to teaching-learning. It is totally 131 pages including both 'general outline' and 'details'. The VCR material and its guidebook consist of contents that cultivate the good attitude trying to economize energy and raise student's interests with a purpose of strong motivation to recognize the necessity of economy and practice it. After establishing development direction of VCR material through discussion meetings and research trips, its script was made by relevant experts. Then the script was also reviewed two times. The drafted VCR material made by a video material developing expert was examined and modified by previews twice. After completion of VCR material, the VCR guidebook was made. All these procedures led to the development of VCR material which runs 20 minutes in VHS type. The VCR guidebook shows a production purpose of the program, structure of contents, evaluation methods, and contents of the program in detail to give help to instructors when they use this VCR material, When these energy education materials are used, it is desirable that the VCR material should be presented first to induce student's motive, and then material for student is introduced Since the material for student is composed of activity-oriented modules and each module is independent one another in general, and each activity is, too. the necessary module or activity can be chosen and utilized in any order according to school or class conditions. This energy education materials will contribute to the development of student's ability to solve energy problem in everyday life and teacher's ability to teach the fundamental knowledge and method in solving energy problem.

• Korean Journal of Materials Research
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• v.20 no.5
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• pp.246-251
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• 2010

The composite photocatalysts of a Fe-modified carbon nanotube (CNT)-$TiO_2$ were synthesized by a two-step sol-gel method at high temperature. Its chemical composition and surface properties were investigated by BET surface area, scanning electron microscope (SEM), Transmission Electron Microscope (TEM), X-ray diffraction (XRD) and ultraviolet-visible (UV-Vis) spectroscopy. The results showed that the BET surface area was improved by modification of Fe, which was related to the adsorption capacity for each composite. Interesting thin layer aggregates of nanosized $TiO_2$ were observed from TEM images, probably stabilized by the presence of CNT, and the surface and structural characterization of the samples was carried out. The XRD results showed that the Fe/CNT-$TiO_2$ composites contained a mix of anatase and rutile forms of $TiO_2$ particles when the precursor is $TiOSO_4{\cdot}xH_2O$ (TOS). An excellent photocatalytic activity of Fe/CNT-$TiO_2$ was obtained for the degradation of methylene blue (MB) under visible light irradiation. It was considered that Fe cation could be doped into the matrix of $TiO_2$, which could hinder the recombination rate of the excited electrons/holes. The photocatalytic activity of the composites was also found to depend on the presence of CNT. The synergistic effects among the Fe, CNT and $TiO_2$ components were responsible for improving the visible light photocatalytic activity.

• Nuclear Engineering and Technology
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• v.51 no.1
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• pp.325-336
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• 2019

The activity concentrations of $^{226}Ra$, $^{232}Th$, and $^{40}K$ from 102 building materials samples were determined using a high-purity germanium (HPGe) detector. The activity concentrations were evaluated for possible radiological hazards to the human health. The excess lifetime cancer risks (ELCR) were also estimated, and the average values were recorded as $0.42{\pm}0.24{\times}10^{-3}$, $3.22{\pm}1.83{\times}10^{-3}$, and $3.65{\pm}1.85{\times}10^{-3}$ for outdoor, indoor, and total ELCR respectively. The activity concentrations were further subjected to RESRAD-BUILD computer code to evaluate the long-term radiation exposure to a dweller. The indoor doses were assessed from zero up to 70 years. The simulation results were $92{\pm}59$, $689{\pm}566$, and $782{\pm}569{\mu}Sv\;y^{-1}$ for indoor external, internal, and total effective dose equivalent (TEDE) respectively. The results reported were all below the recommended maximum values. Therefore, the radiological hazards attributed to building materials under study are negligible.

• Korean Journal of Materials Research
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• v.32 no.1
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• pp.1-8
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• 2022

In this investigation, Bi₂MoO₆ deposited graphene nanocomposite (BMG) was synthesized using a simple microwave assisted hydrothermal synthesis method. The synthesized BMG nanocomposite was characterized by X-ray diffraction, transmission electron microscopy, scanning electron microscopy with energy dispersive X-ray analysis, and photocurrent analysis. The study revealed that the catalysts prepared have high crystalline nature, enhanced light responsive property, high catalytic activity, and good stability. XRD results of BMG composite exhibit a koechlinite phase of Bi₂MoO₆. The surface property is shown by SEM and TEM, which confirmed a homogenous composition in the bulk particles of Bi₂MoO₆ and nanosheets of graphene. The catalytic behavior was investigated by the decomposition of Rhodamine B as a standard dye. The results exhibit excellent yields of product derivatives at mild conditions under ultrasonic/visible light-medium. Approximately 1.6-times-enhanced sono-photocatalytic activity was observed by introduction of Bi₂MoO₆ on graphene nanosheet compared with control sample P25 during 50 min test.

• Korean Journal of Plant Resources
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• v.21 no.1
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• pp.12-18
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• 2008

Antioxidative activity and inhibitory activity of angiotensin I converting enzyme(ACE), aminopeptidase N(APN) and $\alpha$-amylase were investigated in the methanol extracts from 25 fern plants native to Jeju Island, in order to screen the plant species containing bioactive materials for functional foods or medicines. The antioxidative activity was higher in Cytomium fortunei(41.9%) and Rumohra standishii(34.1%) than in leaves of Thea sinensis(30.9%), a small tree for antioxidative beverage. Inhibitory activities of ACE and APN were relatively high in Cytomium fortunei as 26.7% and 28.2% respectively. $\alpha$-Amylase inhibitory activity was higher than 50% in 10 species. Particularly, Cytomium fortunei(87.4%) and Dryopteris erythrosora(71.6%) showed the inhibitory activities higher than those of other form plants. Of 25 fern plants investigated here, Cytomium fortunei showed not only the highest antioxidative activity but also the highest inhibitory activity of ACE, APN and $\alpha$-amylase. It suggests that Cytomium fortunei could be potentially used as a resource of bioactive materials for fuctional foods or medicines.