• Advances in materials Research
• /
• v.3 no.4
• /
• pp.233-242
• /
• 2014

Magnetic and conducting aniline sulfide resin cross-linked (ASC-Fe3O4) nanocomposite has been prepared in the presence of aniline sulfide resin (ASR), aniline, $Fe_3O_4$ coated by polyethylene glycol (PEG) and initiator. The magnetic properties of the resulting composites showed ferromagnetic behavior, such as high-saturated magnetization (Ms= 41 emu/g), and coercive force (Hc=1.5 Oe). The saturated magnetization was increased by increasing of $Fe_3O_4$ content and decreased by increasing aniline ratio. The transmission electron micrograph (TEM) and X-ray diffraction proved that nanometer-sized about 20-30 nm $Fe_3O_4$ in the composite. The average size of ASC-$Fe_3O_4$ nanocomposite with core-shell structure was about 50-60 nm, and polydisperse. This approach may also be extended to the synthesis and modification of other polymers. Electrical conductivity of aniline sulfide resin cross-linked (ASC) nanocomposite has been studied by four-point probe method and produced $3.3{\times}10^{-4}S/cm$ conductivity for it. The conductivity of the composites at room temperature depended on the $Fe_3O_4$, aniline ratio and doping degree. The thermogravimetry analysis (TGA) results showed that this resin is thermal resistance near of $500^{\circ}C$. So, It can be used for resistance thermal coating for military applications. $Fe_3O_4$-PASC nanocomposite has been flexible structure with electrical and magnetic properties.

• Korean Journal of Plant Resources
• /
• v.31 no.3
• /
• pp.228-236
• /
• 2018

In this study, we evaluated the antioxidant activity and protective effects against oxidative DNA damage of the ethyl acetate fraction from the callus of Abeliophyllum distichum Nakai (ECA). Callus of A. distichum was induced on MS medium containing NAA (1 mg/L) and 2,4-D (1 mg/L), and a sufficient amount was obtained for the extraction by subculture. Acteoside was analyzed and quantified (0.39 mg/g callus) from ECA using the high-performance liquid chromatography-photodiode array detector method. ECA showed very high antioxidative activity as revealed by DPPH and ABTS scavenging assays. The $IC_{50}$ values were 12.4 and $6.8{\mu}g/ml$, respectively. ECA showed protective effects against oxidative DNA damage evaluated by using ${\Psi}X-174$ RF I plasmid DNA. It also inhibited DNA damage by suppressing the oxidative stress-induced protein and mRNA levels of ${\gamma}$-H2AX and p53 in NIH/3T3 cells. In conclusion, ECA protects against oxidative DNA damage through its powerful antioxidant activity.

• Journal of The Korean Astronomical Society
• /
• v.37 no.5
• /
• pp.605-609
• /
• 2004

We present a set of high-resolution 3D MHD simulations exploring the evolution of light, supersonic jets in cluster environments. We model sets of high- and low-Mach jets entering both uniform surroundings and King-type atmospheres and propagating distances more than 100 times the initial jet radius. Through complimentary analyses of synthetic observations and energy flow, we explore the detailed interactions between these jets and their environments. We find that jet cocoon morphology is strongly influenced by the structure of the ambient medium. Jets moving into uniform atmospheres have more pronounced backflow than their non-uniform counterparts, and this difference is clearly reflected by morphological differences in the synthetic observations. Additionally, synthetic observations illustrate differences in the appearances of terminal hotspots and the x-ray and radio correlations between the high- and low-Mach runs. Exploration of energy flow in these systems illustrates the general conversion of kinetic to thermal and magnetic energy in all of our simulations. Specifically, we examine conversion of energy type and the spatial transport of energy to the ambient medium. Determination of the evolution of the energy distribution in these objects will enhance our understanding of the role of AGN feedback in cluster environments.

• Proceedings of the Korean Society for Emotion and Sensibility Conference
• /
• 2001.05a
• /
• pp.175-181
• /
• 2001

본 연구의 목적은 사람들이 언어과제와 공간지각과제을 수행하는 동안 활성화되는 뇌 영역의 차이를 규명하는 것이다. 428명의 대학생을 대상으로 집단 심리실험을 수행하여, fMRI 연구를 위한 실험참여자로 17명의 오른손잡이 여대생을 선정하였다. 17명 중 8명은 언어능력은 뛰어나지만 공간지각능력이 떨어지고, 나머지 9명은 언어능력은 빈약하지만, 공간지각능력이 우수한 사람들이었다. fMRI 실험에 사용된 패러다임에는 언어과제와 공간지각과제가 각각 8block으로 구성되었으며, 각 block은 동일한 과제 3문항을 포함하였다. fMRI 이미징은 1.5T Siemens Vision Scanner로 수집되었으며, Single-shot EPI 기법으로 (TR/TE : 3840/40ms, flip angle : 90, FOV : 220, 64x64 matrix) 이미지를 스캔하였다. 자료분석은 SPM-99 소프트웨어를 사용하였다. 감산(subtraction)분석결과, 언어능력이 뛰어난 집단에서는 양측 대상회(bilateral cingulate gyri)와 좌측 상두정엽 (left superior parietal lobe)이 더 많이 활성화되었고, 언어능력이 떨어지는 집단에서는 양측 전두엽 (both frontal lobes)이 더 많이 활성화되었다. 공간지각능력이 떨어지는 집단에서는 우측 시상 (right thalamus)과 좌측 측-후두엽 (left temporooccipital)이 더 많이 활성화되었다. 언어능력이나 공간지각능력이 우수한 집단에서는 공통적으로 대상회 (cingulate gyri)가 활성화되었다.

• Journal of Korea Society of Digital Industry and Information Management
• /
• v.10 no.2
• /
• pp.13-20
• /
• 2014

In this paper, we implemented the object scanning with nxtOSEK which is an open source platform. nxtOSEK consists of device driver of leJOS NXJ C/Assembly source code, TOPPERS/ATK(Automotive real time Kernel) and TOPPERS/JSP Real-Time Operating System source code that includes ARM7 specific porting part, and glue code make them work together. nxtOSEK can provide ANSI C by using GCC tool chain and C API and apply for real-time multi tasking features. We experimented the 3D scanning with ultra sonic and laser sensor which are made directly by laser module diode and experimented the measurement of scanning the object by knowing x, y, and z coordinates for every points that it scans. In this paper, the laser module is the dimension of $6{\times}10[mm]$ requiring 5volts/5[mW], and used the laser light of wavelength in the 650[nm] range. For detecting the object, we used the beacon detection algorithm and as the laser light swept the objects, the photodiode monitored the ambient light at interval of 10[ms] which is called a real time. We communicated the 3D scanning platform via bluetooth protocol with host platform and the results are displayed via DPlot graphic tool. And therefore we enhanced the functionality of the 3D scanner for identifying the image scanning with laser sensor modules compared to ultra sonic sensor.

• 한국신재생에너지학회:학술대회논문집
• /
• 2011.05a
• /
• pp.93.2-93.2
• /
• 2011

In this work, graphite nanofibers (GNFs) were prepared for using catalyst supports in fuel cells. The GNFs were chemically activated to obtain high surface area and small pore diameter with different potassium hydroxide (KOH) amounts, i.e., 0, 1, 3, 4, and 5 g as an activating agent. And then Pt-Ru was deposited onto activated GNFs (A-GNFs) by chemical reduction method. The characteristics of Pt-Ru catalysts deposited onto A-GNFs were determined by specific surface area and pore size analyzer, X-ray diffraction (XRD), transmission electron microscopy (TEM), and inductive coupled plasma-mass spectrometer (ICP-MS). The electrochemical properties of Pt-Ru/A-GNFs catalysts were also analyzed by cyclic voltammetry (CV) experiments. From the results, the A-GNFs carbon supports activated with 4 g of KOH (A4g-GNFs) showed that the highest specific surface areas. In addition, the A4g-GNFs led to uniform dispersion of Pt-Ru onto A4g-GNFs, resulting in the enhancement of electrochemical activity of Pt-Ru catalysts.

• Journal of the Korean Society of Combustion
• /
• v.4 no.2
• /
• pp.23-33
• /
• 1999

A turbulent non-premixed ethylene flame, which was set up in a vertical wind tunnel, was examined to understand the effect of turbulent mixing on formations of soot and gaseous species in the flames. Temperature and velocity profiles were measured using uncoated thermocouples and LDV system. Gaseous samples were withdrawn by using a water cooled stainless iso-kinetic gas sampling probe. The samples for inorganic compounds and light hydrocarbons were collected with sampling bottles and were analyzed by a gas chromatography. The samples for aromatic hydrocarbons were collected on a sorbent tube and were analyzed on a GC/MS system. Some of main results were followed. CO and $CO_2$ were measured relatively in early part of flame and the concentration of CO was greater than that of $CO_2$ all over the early flame region due to the scavenging of the oxidizing species OH by soot particles. Aromatic hydrocarbons were measured at x/D=122 along the radial direction and main important species were benzene, xylene, toluene, styrene, indene, naphthalene. The peak points of these compounds occurred at r/D=0.8 apart from the center of flame, around in which the concentration of $C_2H_2$ decayed relatively rapidly from the maximum value.

• Transactions on Electrical and Electronic Materials
• /
• v.6 no.4
• /
• pp.169-172
• /
• 2005

[ $Y_2O_3:Eu$ ] powder was synthesized using a solution-combustion method by dissolving $(CH_3CO_2)_3Y$ and $(CH_3CO_2)_3$ Eu in methyl-alcohol solution. Results from X-ray diffractometery (XRD), thermogravimetry (TG)-differential thermal analysis (DTA) show that $Y_2O_3:Eu$ crystallizes completely when the dry powder is sintered at $500^{\circ}C$. The investigated optical properties were the photoluminescence emission spectra, the excitation spectra and luminescence decay curve. Europium (Eu) concentration had no observable effect on the optical spectrum which depended on the emission intensity. The mean lifetime of synthesized phosphors was $2.3\~2.6 ms$.

• Journal of Plant Biotechnology
• /
• v.5 no.4
• /
• pp.245-250
• /
• 2003

An efficient procedure was developed for adventitious shoot bud induction and plantlet regeneration from various explants of the ten genotypes of Pepper (Capsicum annuum L.) using Thidiazuron (TDZ). Among various treatments at 1.0-3.0 mg/L TDZ Induced maximum number of adventitious shoots depending upon the explant type and genotype compared to other treatments. Among the explants tested, leaf induced maximum number of adventitious shoots than the cotyledons. TDZ-mediated organo-genesis was possible in 10 pepper cultivars, the extent of the response being genotype-dependent. Of the ten genotypes tested, C. annuum cvs CA960, $G_4$ and X-235 were produced maximum number of adventitious shoots and Sell was the least, and all other genotypes gave moderate response. Elongation of multiple shoots was observed on medium supplemented with SA (0.05 mg/L) in combination of IAA (0.05 mg/L). Differences in ability for in vitro shoot regeneration and elongation depend upon the variety and explant type. The elongated shoots were success. Fully rooted on MS medium containing at 1.0 mG/L IAA. Plantlets regenerated from different explants of ten genotypes were found to be diploid (2n=24) and were devoid of any chromosomal aberrations. Regenerated plants were successfully established in soil where 85-90% of them developed into morphologically normal and fertile plants.

• Bulletin of the Korean Chemical Society
• /
• v.35 no.12
• /
• pp.3535-3541
• /
• 2014

Bisphenol A is considered as pollutant, because it is toxic and hazardous to living organisms even at very low concentrations. Biological oxidation used for removing this organic from waste water is not suitable and consequently application of catalytic wet oxidation has been considered as one of the best options for treating bisphenol A. We have developed Fe/SBA-15, Ni/SBA-15 and Fe-Ni/SBA-15 as heterogeneous catalysts using the advanced impregnation method for oxidation of bisphenol A in water. The catalysts were characterized with physico-chemical characterization methods such as, powder X-ray diffraction (PXRD), FT-IR measurements, N2 adsorption-desorption isotherm, thermo-gravimetric analysis (TGA), scanning electron microscopy (SEM), transmission electron microscopy (TEM) and inductively coupled plasma optical emission spectroscopy (ICP-OES) analysis. This work illustrates activity of the catalysts for heterogeneous catalytic degradation reaction revealed with excellent conversion and recyclability. The degradation products identified were not persistent pollutants. GC-MS analysis identified the products: 2,4-hexadienedioic acid, 2,4-pentadienic acid and isopropanol or acetic acid. The leachability study indicated that the catalysts release very little metals to water. Therefore, the possibility of water contamination through metal leaching was almost negligible.