• Journal of the Korean Crystal Growth and Crystal Technology
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• v.25 no.6
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• pp.239-244
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• 2015

Lead zirconate titanate (PZT) thick films with thickness of $10{\sim}20{\mu}m$ were fabricated on silicon substrate by aerosol deposition method. As-deposited films on silicon were annealed at the temperatures of $700^{\circ}C$. The electrical properties of films deposited by PZT powders were characterized using impedance analyzer and Sawyer-Tower circuit. The PZT powder was prepared by both conventional solid reaction process and sol-gel process. The remanent polarization, coercive field, and dielectric constant of the $10{\mu}m$ thick film with solid reaction process were $20{\mu}C/cm^2$, 30 kV/cm and 1320, respectively. On the other hand, the PZT films by sol-gel process showed a poor dielectric constant of 635. The reason was probably due to the presence of pores produced from organic residue during annealing.

• The Journal of Korea Institute of Information, Electronics, and Communication Technology
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• v.2 no.1
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• pp.3-9
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• 2009

Although Active matrix organic light emitting diode (AMOLED) display has a better image quality in terms of viewing angle, contrast ratio, and response time than liquid crystal displays (LCDs), it still has some critical issues such as lifetime, residual images, and brightness non-uniformity due to non-uniformity in electrical characteristics of driving TFTs and IR drops on supplied power line. Among them, we improved irrecoverable residual images of AMOLED displays which is mainly related to the hysteresis characteristics of driving TFTs. We consider four kinds of surface treatment conditions before gate oxide deposition for improving hysteresis characteristics. We can reduce the hysteresis level of p-channel TFT to 0.23 V, interface trap states between the poly-Si layer and gate insulator to $3.11{\times}10^{11}cm^{-2}$, and output current variation of p-channel TFT to 3.65 % through the surface treatment using ultraviolet light and H2 plasma. Therefore, the recoverable residual image problem of AMOLED displays can be improved by surface treatment using ultraviolet light and $H_2$ plasma.

• Korean Journal of Clinical Pharmacy
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• v.15 no.1
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• pp.46-49
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• 2005

A simple HPLC method was employed for the determination of pentoxifylline in human serum. After addition of internal standard (IS, 50 uL of 3 ug/mL chloramphenicol methanol solution) into the serum sample, the drug and IS were extracted by dichloromethane. Following a 1-min vortex-mixing and a 15-min centrifugation at 3500 게m, the organic phase was transferred and evaporated to dryness under a vacuum. The residue was reconstituted with 120 ${\mu}L$ of mobile phase and 50 ${\mu}L$ was injected into C18 column with a mobile phase composed of 0.034 M phosphoric acid adjusted to pH 4 with 10 M NaOH and acetonitrile (75:25, v/v). The samples were detected using an ultraviolet detector at 273 nm. The method was simple, specific and validated with a limit of 10 ng/mL. Intra- and inter-day precision and accuracy were acceptable for all quality control samples including the lower limit of quantification. The applicability of this method was evaluated by analysis of human serum after oral administration of a single 400 mg dose to 8 healthy subjects. The pharmacokinetic parameters for pentoxifylline in human subjects were calculated using WinNonlin program. As a result, $AUC_{t},\;C_{max},\;T_{max}$ and $t_{1/2}$ were $962.28{\pm}645.69\;ng{\cdot}/mL$, $132.82{\pm}42.05$ ng/mL, $2.06{\pm}2.68$ hr and $8.74{\pm}4.38$ hr, respectively. Based on the results, this validated method appears to be useful fur the pharmnacokinetic study of pentoxifylline in humans.

• KSBB Journal
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• v.30 no.6
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• pp.291-295
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• 2015

The limited productivity of natural shell matrix proteins has hampered the investigation of their biochemical properties and practical applications, although biominerals in nature obtained by organic-inorganic assemblies have attractive mechanical and biological properties. Here, we prepared a vector for the expression of a fusion protein of a shell matrix protein from Pinctada fucata (named as GRP_BA) with the GRGDSP residue. The fusion protein of BA-RGD was simply produced in E. coli and purified through sequential steps including the treatment with $CaCl_2$ and EDTA solution for cell membrane washing, mechanical cell disruption and the application of non-ionic surfactant of Triton X-100 for BA-RGD inclusion body washing. The production yield was approximately 60 mg/L, any other protein band was not observed in SDS-PAGE and it was estimated that above 97% endotoxin was removed compared to the endotoxin level of whole cell. This study showed this simple and easy purification approach could be applied to the purification of BA-RGD fusion protein. It is expected that the protein could be utilized for the preparation of biominerals in practical aspects.

• Korean Journal of Environmental Agriculture
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• v.33 no.4
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• pp.414-418
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• 2014

BACKGROUND: Benzene, toluene, ethylbenzene and xylene (BTEX), which are volatile aromatic hydrocarbons and main constituents of gasoline, are neuro-carcinogenic organic pollutants in soil and groundwater. Korea Ministry of Environment has established the maximum permissible level of BTEX in arable soil to 1, 20, 50 and 15 mg/kg, respectively. METHODS AND RESULTS: To understand an arable soil contamination by BTEX, we collected 92 samples from the arable lands around oil reservoir, and analyzed the BTEX residue using a GC-MS with head-space sampler. A linear correlation between BTEX concentration and peak areas was detected with coefficient correlations in the range of 0.9807-0.9995. The method LOQ of BTEX was 0.002, 0.014, 0.084, and 0.038 mg/kg, respectively. Recoveries of 0.5 mg/kg BTEX were found to be 73.7-96.9%. The precision was reliable since RSD percentage (0.7-7.5%) was below 30, which was the normal percent value. Also, BTEX in all samples were detected under the LOQ. CONCLUSION: These results showed that the investigated arable soils around airport and oil reservoir in Korea were not contaminated by oils.

• Analytical Science and Technology
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• v.12 no.2
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• pp.151-158
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• 1999

This study was conducted to measure the residual PCBs in sediments of 4 great rivers in Korea by gas chromatography-mass spectrometry. From the results, PCBs were positively detected in all samples. The residue levels of total PCBs in sediments in near of SS and OS were $290.87{\mu}g/kg$ and $221.11{\mu}g/kg$, respectively. The PCBs contamination may be in association with total organic compound (TOC) in sediments. Congener 66, 74, 90, 101, 105, 110, 118, 138, 149, 153, 180, 187 as IUPAC No were predominant species found in sediments and the polyCBs detected most aboundantly in sediments were tetraCBs and pentaCBs. From the study, it appears that the PCBs contamination in sediments of 4 great rivers is not serious and the analysis from enough many sites is needed for the next survey.

• Journal of environmental and Sanitary engineering
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• v.18 no.1
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• pp.58-67
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• 2003

The characteristics of the commercial garbage-decomposing accelerant, Raw Material of Pomia(RMP), Pomia and Vitabio. were analyzed. In HPLC pattern, Pomia and Vitabio showed main peak of about 30kDa in 280nm wave length. RMP, Pomia and Vitabio showed three, two and two peaks in 210nm. K and Na ion content of RMP were 2,620 and 1,590ppm, respectively, and their content were the largest one among others. Ca, Mg and Mn ion content of RMP were also the largest one, but Zn ion content was the least one. $Cl^{-}$, $F^{-}$ and $NO_3^{-}$ ion content of RMP were the largest one, especially $Cl^{-}$ content was 3,553ppm. pH values of RMP and Pomia were in neutral region, but Vitabio was 9.03. Dried residue content of RMP, Pomia and Vitabio were 1.4%, 0.55% and 0.4%, respectively. The number of general bacteria on PCA plate from RMP, Pomia and Vitabio were 2.2{\times}10^{6}cfu/ml,{\;}6.5{\times}10^{3}cfu/ml{\;}and{\;}1.1{\times}10^{3}cfu/ml$, respectively. The number of facultative anaerobes of RMP was $4.4{\;}{\times}{\;}10^{4}cfu/ml$, and it was biggest one. Lactobacilli and yeasts were found less than 10cfu/ml at best. The bacterium exists in RMP in high frequency was identified as Bacillus subtilis. Volatile sulfur compound amount of garbage samples treated with Pomia and Vitabio in concentration of 1/500 at $33^{\circ}C$ for 8 days were 1,273ppb and 1,902ppb, respectively, and control showed 3,015ppb. Volatile organic compound amount of the garbage samples treated were 68,312ppb, 124,317ppb and 263,954ppm, respectively. Diethylamine that known as malodor compound were 5,107ppb, 261ppb and 11,124ppb, respectively.

• Korean Journal of Agricultural Science
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• v.37 no.1
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• pp.1-6
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• 2010

Allelopathic activity of rotation crop residues to common weeds and selectivity of crops were studied for developing an alternative weed control strategy in upland organic farming. All rotation crop residues with various ratios suppressed weed growth, but the growth of crop species stimulated a little when those were grown with the mixture of rotation crop residues except a few crop species. Among the rotation crop residues used in this study hairy vetch was the most effective, followed by Chinese milkvetch, barley and rye in suppression of weed growth. The 90:10 (crop:soil, v/v) treatments incorporation rate of crop residues such as hairy vetch and Chinese milkvetch suppressed completely the growth of all weed species tested in this study. The effect of crop residues on suppression of weed growth reduced to 90% when the incorporation rates decreased to 60% [60:40 (crop:soil, v/v). It was noticed that broadleaf weed species were more susceptible to rotation crop residues than grass weed species. In the influence of crop residues on the crop growth, no growth inhibition was found in red pepper, lettuce and perllia at any incorporation rates, but tomato, cucumber and corn were slightly inhibited in a few cases at their highest incorporation levels. This study demonstrated that rotation crop residues especially hairy vetch and Chinese milkvetch have high herbicidal effects against weeds without inhibiting the growth of crop species.

• ALGAE
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• v.24 no.1
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• pp.47-55
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• 2009

Recently, interest in plant-derived food additives has developed natural antioxidants, in order to alternate syn-thetic antioxidants with several disadvantages. In the present study, different organic fractions from solvent parti-tions of 80% methanol extract from Jeju benthic diatoms, Achnanthes longipes, Navicula sp. and Amphora coffeaeformis was assessed for their potential antioxidant effects. Among the solvent fractions tested, n-hexane (80.4%) and 80% methanol extract (76.6%) from A. longipes, chloroform (63.2%) from Navicula sp. and n-hexane (67.4%) from A. cof-feaeformis were effective in DPPH free radical scavenging. Fractions of chloroform (53.4%) and n-hexane (53.1%) from A. longipes exhibited higher activities on $H_2O_2$ scavengin. Fraction of n-Hexane from A. longipes exhibited the highest hydroxyl radical scavenging activity and NO. scavenging activity (56.5% and 75.6%, respectively). Aqueous residue from A. coffeaeformis (75.6%) showed the highest metal chelating effect. chloroform and ethyl acetate frac-tion of all the diatoms exhibited significant antioxidant activities in lipid peroxidation inhibitory activity. In particu-lar, both chloroform and the ethyl ecetate fraction from A. longipes and A. coffeaeformis exhibited lipid peroxidation inhibitory activity significantly higher than that of $\alpha$- tocopherol. These data suggest that the Jeju benthic diatoms tested are rich in hydrophilic and hydrophobic antioxidative compounds with different antioxidative properties that can be applied in food industry.

• YAKHAK HOEJI
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• v.11 no.1_2
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• pp.7-16
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• 1967

A yellowish microneedles, $C_{28}$ H$_{32}$ $O_{14}$ ${\cdot}$ I$_{1}$/$_2$, H$_{2}$O, m.p.262-$4^{\circ}$ , [${\alpha}$$_{D}^{20}$= -71,$43^{\circ}$(C = 0.42, pyridine), its acetate m.p.123-5.deg., were obtained in 0.3% yield from the leaves of Chrysanthemum sibiricum F$_{ISCHER}$. This substance is insoluble in water and the usual organic solvents except pyridine and ethylene glycol and, is not decomposed by dilute mineral acids but undergoes decomposition on being boiled in 60% H$_{2}$SO$_{4}$ or 35% HCl, giving one moel each of acacetin, glucose and rhamnose. It was not hydrolysed with a rhamnodiastase preparation obtained from the seeds of Rhamnus koraiensis. After permethylation of it, the uncrystallized product was hydrolysed and apigenin-5,4'-dimethyl ehter, m.p.$262^{\circ}$ was obtained, indicating that the disaccharide residue is at the 7 position of acacetin. Partial hydrolysis of this acacetin-7-rhamnoglucoside in cyclohexanol with formic acid gave acacetin-7-glucoside, m.p.246.deg. and rutinose, identifying them with authentic specimen on a paper chromatography. It was thus identified as linarin(acacetin-7-rutinoside) by means of mixed fusion, of paper partition chromatography and of its derivatives. Zemplen and Bognar suggested that the glucosidic linkage of linarin is .betha. by means of synthesis of this substance. But there is no evidence whether it is hydrolysed by emulsin or maltase or not. Linarin itself was not hydrolysed by an emulsin existing in the seed of Apricot or a maltase, but acacetin-7-glucoside(tilianin) which obtained from linarin gave acacetin and glucose on hydrolysis with the same emulsin and accordingly the glucosidic linkages of linarin and tilianin are thus regarded as ${\beta}$.