• Restorative Dentistry and Endodontics
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• v.38 no.4
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• pp.234-240
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• 2013

Objectives: This study evaluated the effects of intraradicular moisture on the pushout bond strength of a fibre post luted with several self-adhesive resin cements. Materials and Methods: Endodontically treated root canals were treated with one of three luting cements: (1) RelyX U100, (2) Clearfil SA, and (3) G-Cem. Roots were then divided into four subgroups according to the moisture condition tested: (I) dry: excess water removed with paper points followed by dehydration with 95% ethanol, (II) normal moisture: canals blot-dried with paper points until appearing dry, (III) moist: canals dried by low vacuum using a Luer adapter, and (IV) wet: canals remained totally flooded. Two 1-mm-thick slices were obtained from each root sample and bond strength was measured using a push-out test setup. The data were analysed using a two-way analysis of variance and the Bonferroni post hoc test with p = 0.05. Results: Statistical analysis demonstrated that moisture levels had a significant effect on the bond strength of luting cements (p < 0.05), with the exception of G-Cem. RelyX U100 displayed the highest bond strength under moist conditions (III). Clearfil SA had the highest bond strength under normal moisture conditions (II). Statistical ranking of bond strength values was as follows: RelyX U100 > Clearfil SA > G-Cem. Conclusions: The degree of residual moisture significantly affected the adhesion of luting cements to radicular dentine.

• Magazine of the Korea Concrete Institute
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• v.9 no.2
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• pp.153-161
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• 1997

In the concrete st~uctures exposed to the environmental condition, the water movement is occurred by thc moisture difilsion, and the rnoisturrt distribution in concwt.c is nonunifhrm. Such a non-unif'orm moisture distribution causes tht. diflbrent.ia1 drying shrinkage in concrete structures. From this typc. of' dif'fercntial drying shrinkagr' tensiit-1 stress is occurred in exposure surface of concrete structures. and may result in crack formation. This residual stress is significantly affected by the creep of concrete, and the differential creep is also occurred at the cross section of concrete structures due to moisture difference at each locations. In this study, based on the moisture diffusion theory, a finite element program which is capable of simulating the moisture distribution in concrete was developed. And the analysis method for the differential drying shrinkage was suggested, in which the differential creep was considered. The differential drying shrinkage strain was also measured at various positions of concrete. Finally the validity of analysis method was proved by comparing test results with analytical results.

• Proceedings of the Korea Concrete Institute Conference
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• 2008.04a
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• pp.465-468
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• 2008

This study investigated the best condition when mixed sand with a river and crushed sand was used though the experiment for the properties of the concrete corresponding to the control of fine aggregate ratio to apply the mixed sand and properties of the fine aggregate at the ready-mixed concrete factory on Yeongnam and Honam. The physical properties of Yeongnam and Honam is satisfied with KS F 2526 and KS F 2527 except fineness modulus and passing amount of 8mm sieve. And, the mixed sand above two types which were incongruent to use individually was being used at each factory, and it was managed in accordance with KS. The flowabillity of the mixture proportion of concrete which was estimated by method of unit volume weight according to the fine aggregate ratio at each factory on Yeongnam and Honam was higher than existing mixture proportion. It was analyzed that the residual water due to decline of the surface area caused by reducing fine aggregate ratio was increased relatively. Accordingly, it was considered that the effect on the economic mixture proportion and improvement of durability might be possible.

• Journal of Advanced Marine Engineering and Technology
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• v.37 no.5
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• pp.484-492
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• 2013

With the industrial acceleration in a lot of countries of the world, the demand for anti-corrosion and anti-abrasion material increases continuously. Particularly, stainless steel with the fine surface and excellent corrosion resistance is widely used in various industrial fields including ship, offshore structures tidal power plant, and etc. In marine environment, however, it is easy to generate by the corrosion damage by $Cl^-$ ion and cavitation damage due to high rotation speed on stainless steel. Therefore, in this research, the cavitation erosion-corrosion test (Hybrid test) was performed for 304 stainless steel specimen used in the high flow rate seawater environment. And the cavitation damage behavior in the corrosive environment was analyzed overall. The high hardness was shown due to the formation of compressive residual stress by the water cavitation peening effect in cavitation condition. However, high current density in the potentiodynamic polarization experiment presented with the breakdown of the passive film caused by physical impact. Therefore, both electrochemical characteristics and mechanical properties must be taken into account to improve the cavitation resistance in seawater.

• Korean Journal of Crystallography
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• v.6 no.2
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• pp.111-117
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• 1995

TiO2 thin films were prepared on a (100)silicon wafer using a chemical vapor deposition(CVD) method. The deposition experiments were performed using the TTIP in the deposition temperature ransing from 200 content. The deposition rate of TiO2 was increased with the substrate temperature and the oxygen content. The thickness of the deposited thin film and the compositional analysis of this thin films with theoxygen content were measured using Ellipsometry, SEM and ESCA, respectively. The deposited thin film was composed of a bilayer, external TiO2 and internal Ti. Carbon as a residual impurity was found to remain when zero sccm O2 was purged into a reaction chamber and the composition of the deposited thin film was found to change Ti into TiO in a deeper layer. However, when 600sccm O2 was supplied to a reaction chamber, it has been found to reside less carbon content than without O2. Finally, in the condition of 1200sccm O2, no impurity level of carbon was observed and a deeper layer consisted of the Ti composite, even though the deposited surface was composed of TiO2.

• Proceedings of KOSOMES biannual meeting
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• 2017.11a
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• pp.236-236
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• 2017

Effluent treated by an NaDCC injection method in Ballast water management system (BWMS) contains reactive chlorine species and disinfection by-products (DBPs). In this study, we conducted whole effluent toxicity (WET) testing and ecological risk assessment (ERA) to investigate its ecotoxicological effects on marine environment. WET testing was carried out for four marine pelagic and freshwater organisms, i.e., diatom Skeletonema costatum, Navicula pellicuosa, chlorophyta Dunaliella tertiolecta, Pseudokirchneriella subcapitata, rotifer Brachionus plicatilis, Brachionus calyciflorus and fish Cyprinodon variegatus, Pimephales promelas. The biological toxicity test revealed that algae was the only biota that showed apparent toxicity to the effluent; it showed no observed effect concentration (NOEC), lowest observable effect concentration (LOEC) and effect concentration of 50% (EC50) values of 25-50%, 50-100% and >100%, respectively, at three water condition, but did not show any significant toxicities on other biota. Meanwhile, chemical analysis revealed that the BWMS effluent contained total residual oxidants (TROs) below $0.03{\mu}g/L$ and a total of 25 DBPs such as bromate, volatile halogenated organic compounds (VOCs), halogenated acetonitriles (HANs), halogenated acetic acids (HAAs), chloropicrin and Isocyanuric acid. Based on ERA, the 25 DBPs were not considered to have persistency, bioaccumulation and toxicity (PBT) properties. The ratio of predicted environmental concentration (PEC) to predicted no effect concentration (PNEC) of the other DBPs did not exceed 1 for General harbor environment. However, four substances (Isocyanuric acid, Tribromomethane, Chloropicrin and Monochloroacetic acid) were exceed 1 for Nearship environment. But observed toxicity in the test water on algal growth inhibition would be mitigated by normal dilution factor of 5 applied for nearship exposure. Thus, our results of WET testing and ERA showed that the BWMS effluent treated by NaDCC injection method would have no adverse impacts on marine environment.

• Journal of Life Science
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• v.24 no.6
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• pp.694-699
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• 2014

Indigenous microorganisms play decisive roles in biodegradation. In this study, eighty strains of hydrocarbon-degrading microbes were isolated from Incheon Bay. Among them, 12 strains were selected by an oil film collapsing method. The bacterial strain 'Incheon9' was eventually selected based on its relatively higher lipase and emulsification activities, and was identified as Acinetobacter sp. (NCBI accession code: KF54854). The optimum condition for the growth and emulsification activity of Acinetobacter sp. Incheon9 was $20^{\circ}C$, pH 7, and 1% NaCl. The optimum time for the best production of biosurfactant was 72 hrs. The oil degradation ability of Acinetobacter sp. Incheon9 was investigated by measuring the residual oils in the culture medium by gas chromatography (FID). This research provides foundational data for eco-friendly environmental remediation by microorganisms.

• Journal of the Korean Geotechnical Society
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• v.34 no.5
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• pp.37-51
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• 2018

The slope failure due to the rainfall infiltration occurs frequently in Korea, since the depth of the weathered residual soil layer is shallow in mountainous region. Depth of the failure surface is shallow and tends to pass near the interface between impermeable bedrock and soil layer. Soil parameters that have a significant impact on the instability of unsaturated slopes due to rainfall infiltration inevitably include large uncertainties. Therefore, this study proposes a probabilistic analysis procedure by Monte Carlo Simulation which considers the hydraulic characteristics and strength characteristics of soil as random variables in order to predict slope failure due to rainfall infiltration. The Green-Ampt infiltration model was modified to reflect the boundary conditions on the slope surface according to the rainfall intensity and the boundary condition of the shallow impermeable bedrock was introduced to predict the stability of unsaturated soil slope with shallow bedrock under constant rainfall intensity. The results of infiltration analysis were used as inputs of infinite slope analysis to calculate the safety factor. The proposed analysis method can be used to calculate the time-dependent failure probability of soil slope due to rainfall infiltration.

• Journal of the Korean Society of Food Science and Nutrition
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• v.21 no.2
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• pp.175-180
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• 1992

For the effective utilizing of polyunsaturated lipids in filefish viscera wasted from marine manufactory the conditions of degumming, deacidification, decoloring and deodorization for the processing of refined viscera oil were investigated. In the process of refining degumming with 20$m\ell$ of 4% oxalic acid per 100$m\ell$ of crude filefish viscera oil resulted in the lowest residual phosphorus content as 115.8 ppm and optimal condition to neutralize the filefish viscera oil was treating for 30min at 60$^{\circ}C$ with 0.5% excess of 4M sodium hydroxide solution. Decoloring was optimized by adding 10% bleaching earth and treating for 20min at 60$^{\circ}C$ under vacuum, and deodorizing was done by steam distillation at 180$^{\circ}C$ under 4 torr of vacuum.

• Genomics & Informatics
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• v.13 no.2
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• pp.45-52
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• 2015

Acute myeloid leukemia is a well characterized blood cancer in which the unnatural growth of immature white blood cell takes place, where several genes transcription is regulated by the micro RNAs (miRNAs). Argonaute (AGO) protein is a protein family that binds to the miRNAs and mRNA complex where a strong binding affinity is crucial for its RNA silencing function. By understanding pattern recognition between the miRNAs-mRNA complex and its binding affinity with AGO protein, one can decipher the regulation of a particular gene and develop suitable siRNA for the same in disease condition. In the current work, HOXA9 gene has been selected from literature, whose deregulation is well-established in acute myeloid leukemia. Four miRNAs (mir-145, mir-126, let-7a, and mir-196b) have been selected to target mRNA of HOXA9 (NCBI accession No. NM_152739.3). The binding interaction between mRNAs and mRNA of HOXA9 gene was studied computationally. From result, it was observed mir-145 has highest affinity for HOXA9 gene. Furthermore, the interaction between miRNAs-mRNA duplex of all chosen miRNAs are docked with AGO protein (PDB ID: 3F73, chain A) to study their interaction at molecular level through an in silico approach. The residual interaction and hydrogen bonding are inspected in Discovery Studio 3.5 suites. The current investigation throws light on understanding of AGO-assisted miRNA based gene silencing mechanism in HOXA9 gene associated in acute myeloid leukemia computationally.