• Korean Chemical Engineering Research
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• v.44 no.2
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• pp.160-165
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• 2006

A Pd-Cu-Ni alloyed hydrogen membrane has fabricated on porous nickel support formed by nickel powder. Porous nickel support made by sintering shows a strong resistance to hydrogen embrittlement and thermal fatigue. Plasma surface modification treatment is introduced as pre-treatment process instead of conventional HCl wet activation. Nickel was electroplated to a thickness of $2{\mu}m$ in order in to fill micropores at the nickel support surface. Palladium and copper were deposited at thicknesses of $4{\mu}m$ and $0.5{\mu}m$, respectively, on the nickel coated support by DC sputtering process. Subsequently, copper reflow at $700^{\circ}C$ was performed for an hour in $H_2$ ambient. And, as a result PdCu-Ni composite membrane has a pinhole-free and extremely dense microstructure, having a good adhesion to the porous nickel support and infinite hydrogen selectivity in $H_2/N_2$ mixtures.

• Korean Journal of Environment and Ecology
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• v.19 no.2
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• pp.162-176
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• 2005

This study was carried out as a field survey and a review of articles to investigate a characteristic of the distribution pattern in Korean endemic Corylopsis coreana. Distribution of Corylopsis coreana was found in Boseung-gun, Gwangyang-si, Suncheon-si, Jeumam-myeon Goheung-gun, Ganjeon-myeon Gurye-gun, Mt, Cheongwan Jangheung-gun, Nogodan Mt. Jiri in Jeollanam-do, Mt. Cheonhwang Namwon-si and Beamsagol and Banyabong Mt. Jiri in Jeollabuk-do, Sancheong-gun, hadong-gun and Namhea-gun in Gyeongsangnam-do and Mt. Backun, Pocheon-si in Gyeonggi-do. Total flora in the distribution region of Coryloplsis coreana was recorded as 242 taxa; 70 families, 159 genus, 216 species, 22 varieties, 4 forma. Ratio of taxonomic categories was consisted of Pteridophyte $5.8\%$, Gymnosperm $3.7\%$, Dicotyledon $18.6\%$ and Monocotyledon $71.9\%$. Ratio of Life cycle styles was Annual $1.7\%$ and Perennial $93.3\%$. Ratio of growth habit was appeared to Herb $44.2\%$, Vine $12.4\%$, Shrub $17.8\%$ and Tree $25.6\%$. The distribution region of Corylopsis coreana found to typical type which distribute in N, NE or NW slope. The native Corylopsis coreana of Sinjeonri Sungju-eup in Jellanam-do appeared to have a declining tendency which was caused by influence of tree lager.

• Journal of the Society of Cosmetic Scientists of Korea
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• v.30 no.3 s.47
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• pp.405-408
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• 2004

Several hydroxamic acid derivatives are synthesized to observe retinoidal effect and transactivation potential for $RAR{\alpha}/{\gamma]$ is screened. Among the synthesized compounds, N-(4-N-hydroxycarbamoyl )phenyl) [4-(tert-butyl )phenyl] carboxamide (2f) showed the best compatibility for potent $RAR{\alpha}/{\gamma].$ The acidic hydroxy of hydroxamic acid was easily deprotonated to form an enolate. A formed enolate has a similar role like that of all-trans-retinoic acid. This is the first example of the hydroxamic acid derivative with retinoidal activity. The retinoidal activity of 2f was further confirmed by enhancing activity for the expression of retinoid-responsive genes. To evaluate the possibility for anti.-aging agent, effect on the expression of MMP-1 was measured comparing with all-trans-retinoic acid and retinol. At 10 uM treatment, compound 2f inhibited the expression of MMP-1. These results suggest that new hydroxamic acid derivative 2f could be used as a promising anti-aging agent.

• Korean journal of applied entomology
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• v.50 no.4
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• pp.289-293
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• 2011

This study was conducted to develop economic injury level (EIL) of onion thrips, Thrips tabaci, on welsh onion (Allium fistulosum L. var) in the early transplanting stage. The changes of welsh onion biomass, yield loss, and T. tabaci density were investigated according to the inoculation periods of T. tabaci. In the early transplanting stage of welsh onion, the yield loss (%) increased with increasing inoculation periods: 17.0, 53.3, 38.4, and 80.8% yield loss in 5, 10, 15, and 20 d inoculation periods, respectively. The relationship between Cumulative Insect Days (CID) of T. tabaci and yield loss (%) of welsh onion was well described by a nonlinear logistic equation. Using the estimated equation, EIL of T. tabaci on welsh onion was estimated to 30 CID per plant based on the yield loss 12% (an empirical gain threshold 5% + marketable rate 93% of welsh onion). ET was calculated to 24 CID, which corresponds to 80% of EIL. Until a more defined EIL-model is developed, the present results should be useful for T. tabaci management in early growth stage of welsh onion. The effect of T. tabaci attack on the yield of welsh onion in late growing season (120 days after transplanting) was also examined. The yield of welsh onion increased at a low population density of T. tabaci and decreased at higher densities, showing a typical over-compensatory response.

• Korean Journal of Optics and Photonics
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• v.19 no.3
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• pp.229-236
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• 2008

The optimum conditions of second harmonic generation (SHG) can be successfully achieved experimentally using single pass and double pass methods of a pumping beam. The beam has a power of several Watts radiated by a DOFA (Diode Laser Oscillator & Fiber Amplifier) system, which is a high power CW wavelength tunable infrared laser system, in a PPLN (Periodically Poled MgO doped Lithium Niobate) nonlinear crystal. In the case of a single pass method, the parameters are the wavelength of 535 nm for SHG and the output power of 245 mW generated from the pumping input beam with wavelength of 1070 nm and the power of 2.45 W at phase matching temperature of $108.9^{\circ}C$. The conversion efficiency of SHG was 10%. In order to enhance the output of SHG, the double pass method of the SHG system of a PPLN using a concave mirror for the retroreflection and a pair of wedged flat windows for phase compensation was also presented. In this double pass system, we obtained the SHG output beam with the wavelength of 535 nm and the maximum power of 383 mW at optimum phase matching temperature of $108.5^{\circ}C$ by using an incident pumping beam with wavelength of 1070 nm and the power of 2.45 W. The maximum conversion efficiency is 15.6%, which is more than that of the single pass method.

• Journal of the Computational Structural Engineering Institute of Korea
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• v.25 no.4
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• pp.287-292
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• 2012

In this study, Multi-Channel Magnetic Flux Leakage(MFL) sensor - based inspection system was applied to monitor the condition of cables. This inspection system measures magnetic flux to detect the local faults(LF) of steel cable. To verify the feasibility of the proposed damage detection technique, an 8-channel MFL sensor head prototype was designed and fabricated. A steel cable bunch specimen with several types of damage was fabricated and scanned by the MFL sensor head to measure the magnetic flux density of the specimen. To interpret the condition of the steel cable, magnetic flux signals were used to determine the locations of the flaws and the level of damage. Measured signals from the damaged specimen were compared with thresholds set for objective decision making. In addition, the magnetic flux density values measured from every channel were summed to focus on the detection of axial location. And, sum of flux density were displayed with threshold. Finally, the results were compared with information on actual inflicted damages to confirm the accuracy and effectiveness of the proposed cable monitoring method.

• Journal of Korea Port Economic Association
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• v.25 no.1
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• pp.87-106
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• 2009

This paper is intended to suggest benchmarking ascension for the Gwangyang Port as a hub for international logistics. Most countries that seek to join. and lead, the global trading system as they work to develop production and logistics systems that establish a reputation for leadership in international logistics. Our focus in this research is on the Gwangyang Port and whether Gwangyang Port is capable of carving out a competitive niche as a hub of international logistics. Our analysis is based on comparison and analysis with benchmark port developments around the world. As proposals to promote and activate Gwangyang Port as a hub for international logistics, we recommended in this paper several benchmarks. First, Gwangyang Port FTZ must strengthen the incentive system for tenant companies and providing an inducement for new global companies. Second, Gwangyang Port needs to moderation of regulation on the investment tenant companies and strengthening one-stop service. Third, it is required to stabilize labor and management relationship and securing of flexibility of labor market. Lastly, Gwangyang Port must strengthen mutual interaction of Free Economic Zone (FEZ), Customs Free Zone(CFZ) and Free trade Zone(FTZ) in Korea.

• Polymer(Korea)
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• v.38 no.6
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• pp.774-781
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• 2014

Acetylenic or phenylethynyl end-capped polyisoimide oligomers ($M_w$ 2500 g/mol, 5000 g/mol) based upon 4,4'-diamino diphenyl ether (4,4'-ODA)/4,4'-oxydiphthalic anhydride (ODPA) and 4,4'-ODA/3,3',4,4'-benzophenone tetracarboxylic acid dianhydride (BTDA) were synthesized by using 4-ethynylaniline (4-EA) or 4-phenylethynyl phthalic anhydride (4-PEPA) as an end capper. The incorporation of ethynyl groups were confirmed by FTIR spectroscopy. The isomerization temperature was influenced by molecular weight as well as the backbone structure of polyisoimides oligomers. Thus, polyisoimide oligomers with molecular weight of 2500 g/mol was found to be imidized at temperature $10^{\circ}C$ lower than that for the oligomers with molecular weight of 5000 g/mol. The crosslinking reaction of ethynyl groups occurred at a higher temperature than that for the isoimide/imide isomerization reaction. These two reactions were totally or partially overlapped on the DSC thermograms for the polyisoimide oligomer end-capped with 4-EA. Kinetics of thermal imidization and crosslinking reactions for the 4,4'-ODA/ODPA polyisoimide oligomers end-capped with 4-PEPA were investigated by performing dynamic DSC experiments at heating rate of $10^{\circ}C/min$. The activation energy and pre-exponential factors were 141 kJ/mol and $1.45{\times}10^{13}min^{-1}$ for the imidization reaction and 177 kJ/mol and $2.90{\times}10^{13}min^{-1}$ for the crosslinking reaction, respectively.

• Korean Journal of Microbiology
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• v.45 no.4
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• pp.339-345
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• 2009

Two lactic acid bacteria (LAB) with high ornithine-producing capacity were isolated from kimchi. Examination of the biochemical features using an API kit indicated that the strains belonged to the members of Weissella genus. They were gram positive, short rod-type bacteria, and able to grow anaerobically with $CO_2$ production. The isolates grew well on MRS broth at $25\sim37^{\circ}C$ and pH of 6.0~7.0. The optimum temperature and pH for growth are $30^{\circ}C$ and pH 6.5. The isolates fermented arabinose, ribose, xylose, glucose but not cellobiose, galactose, raffinose, or trehalsoe. The 16S rDNA sequences of isolates showed 99.6% and 99.7% homology with the Weissella koreensis S5623 16S rDNA (access no. AY035891). They were accordingly identified and named as Weissella koreensis OK1-4 and Weissella koreensis OK1-6, and could produce ornithine from MRS broth supplemented with 1% of arginine at a productivity of 27.01 and 31.41 mg/L/h, respectively. This is the first report on the production of ornithine by the genus Weissella isolated from kimchi.

• Korean Journal of Microbiology
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• v.50 no.4
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• pp.360-367
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• 2014

Candida albicans is an opportunistic and the most prevalent fungal pathogen that can cause superficial and systemic infections in immunocompromised patients. C. albicans can promote the transition from budding yeast to filamentous form, generating biofilms. Infections associated with C. albicans biofilms are frequently resistant to conventional antifungal therapy. Therefore, the development of more effective antifungal drugs related with biofilm formation is required urgently. The roots of Rheum undulatum have been used for medicinal purposes in Korea and China traditionally. The aim of present study was to evaluate the effect of R. undulatum extract upon preformed biofilms of 12 clinical C. albicans isolates and the antifungal activities. Its effect on preformed biofilms was evaluated using XTT reduction assay, and metabolic activity of all tested strains was reduced significantly ($49.4{\pm}6.0%$) at 0.098 mg/ml R. undulatum. The R. undulatum extract blocked the adhesion of C. albicans biofilms to polystyrene surfaces, and damaged the cell membrane integrity of C. albicans which was analyzed by CFDA, AM, and propidium iodide double staining. It caused cell lysis which was observed by Confocal laser scanning and phase contrast microscope after propidium iodide and neutral red staining, respectively. Membrane permeability was changed as evidenced by crystal violet uptake. The data suggest that R. undulatum inhibits biofilm formation by C. albicans, which can be associated with the damage of the cell membrane integrity, the changes in the membrane permeability and the cell lysis of C. albicans.