• Korean Journal of Environmental Agriculture
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• v.20 no.5
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• pp.305-309
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• 2001

Thirty-day-old rice seedlings, IR-20 variety were transplanted into the experimental plots and were sprayed with endosulfan (35% EC) after 52 days at the rate of 0.64 kg a.i/ha. Residues of endosulfan in the plant, soil, and water were found to decrease steadily upto 15 days. A second application of the pesticide was made on the 31st day and the plant was harvested on 56th day after the first application. The residue level on hay and grains was 0.7 ${\mu}g/g$. This level is seven times higher than FAO/WHO-prescribed tolerance level of 0.1 ${\mu}g/g$. Metabolites of endosulfan were traced out in plants, soil, and water during the pre- and post-harvest period.

• Macromolecular Research
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• v.13 no.1
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• pp.14-18
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• 2005

Under irradiation in a microwave oven, six novel poly(amide-imide)s containing tetrahydropyrimidinone, tetrahydro-2-thioxopyrimidine moieties and trimellitic rings in their main chains were synthesized through the polycondensation reaction of N,N'-(4,4'-diphenylether)bis(trimellitimide) diacid chloride with six different derivatives of tetrahydropyrimidinone and tetrahydro-2-thioxopyrimidine in the presence of a small amount of a polar organic medium, such as o-cresol. The polycondensation proceeded rapidly and completed within 7-9 min, producing a series of new poly(amide-imide)s in high yield that showed inherent viscosities in the range 0.33-0.52 dL/g. These poly(amide-imide)s were characterized by elemental analysis, viscosity measurement, thermal gravimetric analysis, solubility test, and FT-IR spectroscopy. All of the polymers were soluble at room temperature in polar solvents such as N,N-dimethylacetamide, N,N-dimethylformamide, dimethylsulfoxide, tetrahydrofuran, and N-methyl-2-pyrrolidone.

• Review of KIISC
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• v.25 no.3
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• pp.52-65
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• 2015

제조 분야의 미래유망기술로써 각광받고 있는 3D프린터 기술은 다양한 방식으로 활용되고 있다. 시제품의 제작비용과 시간을 절감시키고 1인 맞춤형 제품 생산이 가능하게 하였으며, 의료 및 산업분야 전반에 걸쳐 그 시장과 규모는 나날이 증대되고 있다. 하지만 이에 반하여 환경오염, 무기제작, 지적재산권, 의료 윤리 및 규제, 국가 보안 위험 등과 같은 문제점 또한 적지 않게 제기되고 있다. 본 고에서는 정보보호 관점에서 네트워크와 연결된 3D프린터가 가진 잠재적인 취약점에 대해 알아보고, 조직에서 이를 예방하기 위한 관리적 방법에 대해 NIST IR 8023의 생명주기에 기반 한 단계별 위험관리 및 위험평가에 대한 가이드를 제공하고자 한다.

• Journal of the Semiconductor & Display Technology
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• v.17 no.2
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• pp.47-52
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• 2018

The three polyols, poly(trimethylene ether) glycol 2000, poly(tetramethylene ether) glycol 2000 and poly (tetramethylene ether) glycol 1000 were reacted with 4,4-diphenylmethane diisocyanate to get polyurethanes. The synthesized three polyurethanes were measured by FT-IR, NMR for investigating chemical structures. Through two spectroscophical methods, It is found that urethane group exists in the three polymers. From the evaluation of hardness, glass transition temperature, tensile strength, and water resistance, the results showed increasing order of Poly(tetramethylene ether) glycol 1000 > Poly(trimethylene ether) glycol 2000 > Poly(tetramethylene ether) glycol 2000 with the content of hard segment in polyurethane.

• Plant Journal
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• v.16 no.3
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• pp.47-52
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• 2020

This study investigated the methodologies to enhance the corrosion resistance and the ways to measure for subsea equipment made of aluminum. The methodologies for the anticorrosion were cathodic protection, conversion coating, anodizing and organic coating. The simply analyzed ways to measure the corrosion resistance were Scanning Electron Microscope (SEM), Electrochemical Impedance Spectroscopy (EIS), Glow discharge optical emission spectrum spectroscopy (GD-OES), Fourier Transform Infrared Spectroscopy (FT-IR), Transmission Electron Microscopy (TEM), X-ray Photoelectron Spectroscopy (XPS), Scanning Vibrating Electrode Technique (SVET), contact angle and interfacial tension. The most widely used tools for increasing the corrosion resistance were the anodizing and the organic coating. Many ways were evenly used to measure corrosion. The methods more frequently utilized were SEM for the surface investigation and the contact angle to evaluate the corrosion resistance.

• Publications of The Korean Astronomical Society
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• v.32 no.1
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• pp.287-291
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• 2017

We present the results of our mid-infrared (MIR) observations of distant clusters of galaxies with AKARI. The wide-field of view of IRC/AKARI ($10^{\prime}{\times}10^{\prime}$) is ideally suited for studying dust-obscured star-formation (SF) activity of galaxies along the cosmic web in the distant universe. We performed a deep and wide-field $15{\mu}m$ (rest-frame ${\approx}8{\mu}m$) imaging observation of the RXJ1716+6708 cluster (z = 0.81) with IRC. We find that $15{\mu}m$-detected cluster member galaxies (with total infrared luminosities of $L_{IR}{\geq}10^{11}L_{\odot}$) are most preferentially located in the cluster outskirt regions, whilst such IR-luminous galaxies avoid the cluster centre. Our $H{\alpha}$ follow-up study of this field confirmed that a significant fraction of $15{\mu}m$-detected cluster galaxies are heavily obscured by dust (with $AH{\alpha}$>3 mag in extreme cases). The environment of such dusty star-burst galaxies coincides with the place where we see a sharp "break" of the colour-density relation, suggesting an important link between dust-obscured SF activity and environmental quenching. We also report the discovery of a new cluster candidate around a radio galaxy at z = 1.52 (4C 65.22), where we obtained one of the deepest IRC imaging datasets with all the nine filters at $2-24{\mu}m$. This field will provide us with the final, excellent laboratory for studying the dust-enshrouded SF activity in galaxies along the cosmic web at the critical epoch of cluster galaxy evolution with AKARI.

• Journal of Korea Technical Association of The Pulp and Paper Industry
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• v.45 no.1
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• pp.52-58
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• 2013

The effets of the pretreatments of tropical kapok fibers were evaluated in this study in terms of water sorption capacity and oil sorption capacity. The alkali treatments with NaOH resulted in the reduction of lignin, oil and hemicellulose, which were detected with FT-IR spectrum. The reduction of the lyphophilic components such as fat on kapok fiber by the ozone treatments were also measured with FT-IR spectrum. The oil sorption capacity of kapok fiber was decreased by the alkali treatments and the ozone treatments, while the water sorption capacity was increased. The liquid sorption capacity were greatly affected by the mechanical cutting of kapok fiber which exposed the big lumen of kapok fiber. The hydrophilic property of kapok fiber could be controlled by the pretreatments, which would increase the applicability of kapok fiber for preparation of various functional paper products.

• Asian Pacific Journal of Cancer Prevention
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• v.15 no.3
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• pp.1299-1306
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• 2014

Background: Nano-biotechnology is recognized as offering revolutionary changes in various fields of medicine. Biologically synthesized silver nanoparticles have a wide range of applications. Materials and Methods: Silver nanoparticles (AgNPs) were biosynthesized with an aqueous extract of Pterocladiella (Pterocladia) capillacea, used as a reducing and stabilizing agent, and characterized using UV-VIS spectroscopy, Fourier Transform Infra red (FT-IR) spectroscopy, transmission electron microscopy (TEM) and energy dispersive analysis (EDX). The biosynthesized AgNPs were tested for cytotoxic activity in a human hepatocellular carcinoma ($HepG_2$) cell line cultured in Dulbecco's modified Eagle medium supplemented with 10% fetal bovine serum, 1% antibiotic and antimycotic solution and 2 mM glutamine. Bacterial susceptibility to AgNPs was assessed with Staphylococcus aureus, Bacillus subtilis [Gram+ve] and Pseudomonas aeruginosa and Escherichia coli [Gram-ve]. The agar well diffusion technique was adopted to evaluate the bactericidal activity of the biosynthesized AgNPs using Ampicillin and Gentamicin as gram+ve and gram-ve antibacterial standard drugs, respectively. Results: The biosynthesized AgNPs were $11.4{\pm}3.52$ nm in diameter. FT-IR analysis showed that carbonyl groups from the amino acid residues and proteins could assist in formation and stabilization of AgNPs. The AgNPs showed potent cytotoxic activity against the human hepatocellular carcinoma ($HepG_2$) cell line at higher concentrations. The results also showed that the biosynthesized AgNPs inhibited the entire panel of tested bacteria with a marked specificity towards Bacillus subtillus. Conclusions: Cytotoxic activity of the biosynthesized AgNPs may be due to the presence of alkaloids present in the algal extract. Our AgNPs appear more bactericidal against gram-positive bacteria (B. subtillus).

• Journal of the Korean Magnetics Society
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• v.13 no.2
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• pp.47-52
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• 2003

Ferromagnetic tunnel junctions were fabricated by dc magnetron sputtering and plasma oxidation process. The local transport properties of the ferromagnetic tunnel junctions were studied using contact-mode Atomic Force Microscopy (AFM) and the local current-voltage analysis. Tunnel junctions with the structure of sub./Ta/Cu/Ta/NiFe/Cu/Mn$\_$75/Ir$\_$25//Co$\_$70/Fe$\_$30//Al-oxide were prepared on thermally oxidized Si wafers. Al-oxide layers were formed with microwave excited plasma using radial line slot antenna (RLSA) for 5 and 7 sec. Kr gas was used as the inert gas mixed with $O_2$ gas for the plasma oxidization. No correlation between topography and current image was observed while they were measured simultaneously. The local current distribution was well identified with the distribution of local barrier height. Assuming the gaussian distribution of the local barrier height, the ferromagnetic tunnel junction with longer oxidation time was well fitted with the experimental results. As contrast, in the case of the shorter time oxidation junction, the current mainly flow through the low barrier height area for its insufficient oxygen. Such leakage current might result in the decrease of tunnel magnetoresistance (TMR) ratio.

• Korean Journal of Agricultural Science
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• v.17 no.1
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• pp.52-64
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• 1990

As a search for natural antioxidants, antioxdative fractions in Pueraria roots were extracted, identified using column chromatography, thin layer chromatography or high performance liquid chromatography. The components which have most effective antioxidative activities were further identified by IR and GC-MS. Separated antioxidative components were then added to four different oils to examine their antioxidative activities. Yield of extract obtained from pueraria root powder by solvent extraction using four step solvent systems was 2.54%. Antioxidative activity of the extracts was as effective as that of 100 ppm ${\delta}$-tocopherol addition, when 0.1% of the extracts was added to linoleic acid. The strongest antioxidative component of methanol extract of pueraria root was identified as puerarin. Aunioxidative activity of puerarin on lard was more effective than ${\alpha}$-tocopherol, but less effective than ${\delta}$-tocopherol. When the puerarin was added to edible oil and heat treated at $145^{\circ}C$, the acid value was lowest in lard and was highest in soybean oil. Antioxidative activity in terms of carbonyl value, thiobarbituric acid value and anisidine value was most high in palm oil and least in soybean and cottonseed oil.