• Journal of the Korean Society of Safety
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• v.32 no.6
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• pp.54-60
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• 2017

A railway rail will be corroded by the repetitive sea wind and fog in the splash and tidal zone such as Youngjong grand bridge. And these rusts of rail could be increased by increasing service period, and it frequently occurred the safety accidents or disorders in electrical problem. In this study, the sacrificial anode cathodic protection method was proposed as a measures for reducing the corrosion of the railway rails in the oceanic climate conditions. As the results of immersion test using the salt water during four months, the sacrificial anode cathodic protection method using the aluminum anode(Al-anode) was evaluated that a distinct effect on corrosion reduction in the rails. Therefore the sacrificial anode cathodic protection method was experimentally proven that a disorders in aspects electric and signal of railway operation condition such as direct fixation track system in Youngjong grand bridge could be prevented by reducing rust falling from the rail. In addition, the installation conditions of the anodes directly affect the transmission range of corrosion potential, the sectional loss of anode, and the corrosion reduction effect. Therefore, to expect the corrosion reduction effect of rails under the oceanic climate conditions for railway track, it was important to adopted the appropriate spacing of anode installation by considering the actual field conditions.

• Korean Journal of Remote Sensing
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• v.32 no.2
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• pp.185-194
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• 2016

The effect of artificial changes in geographical features on local wind was analyzed at the construction site of bridge and fill-up bank in the southern part of Haui-do. Geographic Information System (GIS) data and Computational Fluid Dynamics (CFD) model were used in this study. Three-dimensional numerical topography based on the GIS data for the target area was constructed for the surface boundary input data of the CFD model. The wind observations at an Automatic Weather Station (AWS) located in Haui-do were used to set-up the model inflows. The seasonal simulations were conducted. The differences in surface wind speed between after and before artificial changes in geographical features were analyzed. The surface wind speed decreases 5 to 20% at the south-western part and below 2% of the spatial average for salt field. There was also marked the effect of artificial changes in geographical features on local wind in the westerly wind case for the target area.

• Journal of Korean Society of Coastal and Ocean Engineers
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• v.5 no.4
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• pp.296-301
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• 1993

A hydrodynamic solution for the lateral spreading of a river plume which was developed by assuming a Gaussian distribution of density difference between a turbulent jet river plume and ambient salt water is verified by the field data in the Nakdong river plume. Effect of the river plume on the transport of fine-grained suspended sediment at the Nakdong Estuary is also examined. The analysis of fold data showed a reasonably good correspondence with the theoretical solution adopted in this work Therefore, the hydrodynamic solution can be used as a useful tool in dealing with the lateral spreading of a river plume. The density stratification due to the existence of a river plume seems to cause a retarded settling of the suspended sediments in the water column. and thus a farther transport of the fine sediment is expected than in the normal steady flow.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.41 no.4
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• pp.456-464
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• 1996

Fructans are the major vegetative storage carbohydrate in wheat(Triticum aestivum L.). The depolymerization of fructans occurs by the sequential removal of terminal fructosyl residues by a specific fructan exohydrolase(FEH). The objective of this study was to isolate and characterize this enzyme in wheat. From stems and sheaths of field-grown wheat(cv. Clark), FEH was purified 356-fold using salt precipitation and a series of chromatographic procedures including size exclusion, anion exchange, and affinity chromatography. FEH had a molecular weight of 63.7 kD and an optima at pH 5.5 and 3$0^{\circ}C$. The $K_{m}$s for $\beta$(2 longrightarrow1) linked oligofructans varied, from 10 to 37mM, with the lowest $K_{m}$ for tetrasaccharide. The $V_{max}$ increased as degree of polymerization (DP) increased. Wheat FEH hydrolyzed only, $\beta$(2 longrightarrow1) linked fructans but not, $\beta$(2 longrightarrow6) linked timothy fructan or sucrose. The role of this FEH in fructan metabolism in wheat is discussed.sed.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.21 no.4
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• pp.169-174
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• 2011

Nanoscale-biodegradable behaviors of synthesized biphasic calcium phosphates (BCP) powders were characterized using X-ray diffraction (XRD), lattice parameter, and field emission microscopy (FE-SEM). The calcined BCP powders in vitro tested in Hank's balanced salt solution (pH = 7.4, $36.5^{\circ}C$) for 3 weeks. The calculated unit cell parameters for BCP have shown lattice distortion and expansion as irregular changes in the a and c-axis after in vitro.

• Bulletin of the Korean Chemical Society
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• v.34 no.12
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• pp.3609-3614
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• 2013

Orthorhombic and hexagonal lanthanum(III) hydroxycarbonate ($LaCO_3OH$) and $Ln^{3+}$-doped $LaCO_3OH$ ($LaCO_3OH:Ln^{3+}$, where Ln = Ce, Eu, Tb, and Ho) powders were prepared by a hydrothermal reaction under ambient pressure and characterized by thermogravimetry, powder X-ray diffraction, infrared and luminescence spectroscopy, and field-emission scanning electron microscopy. The polymorph of $LaCO_3OH$ depended on the reaction temperature, inorganic salt additive, species of $Ln^{3+}$ dopant, and solvent. The calcination of orthorhombic $LaCO_3OH:Ln^{3+}$ (2 mol %) powers at $600^{\circ}C$ yielded a mixture of hexagonal and monoclinic $La_2O_2CO_3:Ln^{3+}$ powders. The relative quantity of the latter increased with decreasing ionic radius of the $Ln^{3+}$ dopant ion and increasing doping concentrations. On the other hand, the calcination of hexagonal $LaCO_3OH:Ln^{3+}$ (2 mol %) powders at $600^{\circ}C$ resulted in a pure hexagonal $La_2O_2CO_3:Ln^{3+}$ powder, regardless of the species of $Ln^{3+}$ ions (Ln = Ce, Eu, and Tb). The luminescence spectra of $LaCO_3OH:Ln^{3+}$ and $La_2O_2CO_3:Ln^{3+}$ were measured to examine the effect of their polymorph on the spectra.

• Corrosion Science and Technology
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• v.6 no.3
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• pp.120-127
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• 2007

In any developing nation major investment goes for infrastructure and it is not exception in India. Good numbers of buildings, bridges, shopping malls, car parks etc. are coming up with steel for sustainable development. Thus protecting the structures from corrosion are the challenges faced by professionals for all types of steel structures. About 3% of GDP is accounted for loss due to corrosion. To combat this up to date corrosion map is called for as the country has wide variation of climatic zones with vastcoastline. Logically organic paint system can be prescribed based on the corrosion rate on bare steel with respect to environment. Present paper will emphasis on the study conducted on two types of structural steel coated with organic paint located in twomarine environment having been exposed for three years, Test coupons made from steels both bare and coated are deployed at two field stations having marine (Digha) and industrial marine (Channai) environments. Various tests like AC impedance DC corrosion, polarisation, salt spray test, $SO_2$ chamber and Raman spectroscopy were carried out both in laboratory on fresh as well as coupons collected from exposure sites. Rust formed on the bare and scribed coated coupons are investigated. It is found that normal marine environment at Digha exhibits higher corrosion rate than polluted marine environment in Channai. Rust analysis indicates formation of ${\propto}$-FeoOH protects or reduces corrosion rate at Channai and formation of non-protective ${\gamma}$-FeoOH increases corrosion rate at Digha. The slower corrosion rate in Channai than at Digha is attributed due to availability of $SO_2$, in the environment, which converts non‐protective rust ${\gamma}$-FeoOH to protective rust ${\propto}$-FeoOH. While comparing the damage on the coated panels it is found that low alloy structural steel provides less damage than plain carbon steel. From the experimentations a suitable paint system specification is drawn for identical environments for low medium and high durability.

• Proceedings of the Korean Vacuum Society Conference
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• 2014.02a
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• pp.127-127
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• 2014

인체 내 소량의 생체성분(혈액, 소변 등)을 감지하는 바이오센서 기술은 질병 진단뿐만 아니라 예방 및 관리로 의료서비스 확대, 개인 맞춤형 진료 및 의료비 감소 효과를 가져올 수 있는 기술이다. 광바이오센서는 광학적인 측정방법을 이용하여 다양한 생화학물질들의 상호 반응을 검출해 낼 수 있는 바이오센서로 현재 활발하게 연구가 진행되고 있다. 광 바이오센서는 생체성분 내에 존재하는 전하를 가진 많은 이온들 및 Salt 농도 등에 영향을 받지 않기 때문에 나노 와이어를 이용한 FET (field-effect transistor)형 바이오센서에 비해 많은 장점을 가지고 있다. 일반적으로 광 바이오센서는 형광물질, 인광물질, 발색물질, 방사선 물질 등의 발광물질을 인식물질에 표지하여 인식물질과 분석물질과의 반응유무를 표지된 발광물질의 광학 신호를 감지하여 분석물질을 검출해내는 표지식 광 바이오센서 기술이 상용화되고 있다. 그러나 이러한 분석 방법은 민감도는 우수하지만 분석 시간이 매우 느리고, 고가의 분석 장비 및 복잡한 제조 공정 등의 단점들을 가지고 있다. 이러한 단점들을 극복하기 위하여 생화학 반응 유무를 표지물질 없이 광학적 방식으로 직접 측정할 수 있는 비표지식 광 바이오센서 기술이 최근 들어 많이 연구되고 있다. 본 논문에서는 광파장 이하의 주기를 가진 주기적 공진 격자 표면에서 일어나는 바이오 항원-항체 반응에 대한 공진 반사 파장을 측정하여 생체성분 내에 존재하는 바이오 항원을 고감도로 검출할 수 있는 비표지식 공진반사광 바이오센서 기술을 소개하고자 한다. 공진반사광 바이오센서를 이용하여 human serum내에 존재하는 심근경색 마커인 troponin I (cTnI), creatine kinase MB (CK-MB), myoglobin (MYO)을 0.1 ng/mL 이하의 농도까지 고감도로 측정할 수 있었다.

• KSBB Journal
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• v.31 no.3
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• pp.158-164
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• 2016

Plant growth promoting (PGP) hormones, which are produced in a small quantity by bacteria, affect in plant growth and development. PGPs play an important role on the crop productivity in agricultural field. In this study, a photosynthetic bacterial strain producing the PGP was isolated from paddy soil. Bacterial isolate was gram negative, rod-shaped and motility positive. From the 16s rRNA gene sequence analysis, the isolate was identified as Rhodobacter capsulatus PS-2. The mass cultivation of R. capsulatus PS-2 was optimized by considering of the carbon, nitrogen and inorganic salt sources. Optimal medium composition was determined as Na-succinate 4.5 g, yeast extract 5 g, $K_2HPO_4$ 1 g, $MgSO_4$ 5 g, per liter. From the result of 500 L fermentation for 2 days using the optimal medium, the viable cells were $8.7{\times}10^9cfu/mL$. R. capsulatus PS-2 strain produced the carotenoid and indole-3-acetic acid (IAA). The carotenoid extraction and quantitative analysis were performed by HCl-assisting method. Total carotenoid contents from R. capsulatus PS-2 culture broth were measured as $7.02{\pm}0.04$ and $6.93{\pm}0.05mg/L$ under photoheterotrophic and chemoheterotrophic conditions, respectively. To measure the productivity of IAA, colorimetric method was employed using Salkowski reagent at optical density 535 nm. The results showed that the highest content of IAA was $197.44{\pm}5.92mg/L$ in the optimal medium supplemented with 0.3% tryptophan.

• Journal of Powder Materials
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• v.24 no.6
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• pp.457-463
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• 2017

Nanosized $Gd_2O_3:Eu^{3+}$ red phosphor is prepared using a template method from metal salt impregnated into a crystalline cellulose and is dispersed using a bead mill wet process. The driving force of the surface coating between $Gd_2O_3:Eu^{3+}$ and mica is induced by the Coulomb force. The red phosphor nanosol is effectively coated on mica flakes by the electrostatic interaction between positively charged $Gd_2O_3:Eu^{3+}$ and negatively charged mica above pH 6. To prepare $Gd_2O_3:Eu^{3+}$-coated mica ($Gd_2O_3:Eu/mica$), the coating conditions are optimized, including the stirring temperature, pH, calcination temperature, and coating amount (wt%) of $Gd_2O_3:Eu^{3+}$. In spite of the low luminescence of the $Gd_2O_3:Eu/mica$, the luminescent property is recovered after calcination above $600^{\circ}C$ and is enhanced by increasing the $Gd_2O_3:Eu^{3+}$ coating amount. The $Gd_2O_3:Eu/mica$ is characterized using X-ray diffraction, field emission scanning electron microscopy, zeta potential measurements, and fluorescence spectrometer analysis.