• Journal of Welding and Joining
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• v.16 no.6
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• pp.59-68
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• 1998

In this study, effects of solidification modes (primary $\delta$-ferrite, primary ${\gamma}$-austenite) on the pit initiation and propagation in the 304L and 316L austenitic stainless steel weld metals were investigated. The solidification mode of weld metal was controlled by the addition of nitrogen to Ar shielding gas. Through the electrochemical experiments (potentiodynamic anodic polarization and potentiostatic time-current transient test) and metallographic examination (microstructure and elemental distribution), the following results were obtained. The more the volume content of nitrogen in the shielding gas were, the lower critical current density for passivity was observed. In comparison with weldments solidified through the primary $\delta$-ferrite solidification mode and the primary ${\gamma}$-solidification mode, the former showed higher critical pitting potential and a longer incubation time for stable pit initiation than the latter. However, in the pit propagation stage the former exhibited a faster dissolution rate than the latter. These results were believed to ee related to the distribution of alloying elements such as Cr, Mo, Ni and S.

• Journal of the Korean Magnetics Society
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• v.13 no.2
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• pp.76-81
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• 2003

Non-linear anisotropic materials were used to simulate the effects of tensile stress in 3D finite element analysis (FEA). FEA was used to calculate the effects of far and near-side pit depth and tensile stress on magnetic flux leakage (MFL) signals. The axial and radial MFL signals were depended on far and near-side double circular pit depth and on the stress, but the circumferential MFL signal was not depended on them. The axial and radial MFL signals increased with greater pit depth and applied stress, but the circumferential MFL signal was scarcely changed.

• International Journal of Computer Science & Network Security
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• v.21 no.3
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• pp.145-152
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• 2021

In the Recent times, various technological enhancements in the field of artificial intelligence and big data has been noticed. This advancement coupled with the evolution of the 5G communication and Internet of Things technologies, has helped in the development in the domain of smart mine construction. The development of unmanned vehicles with enhanced and smart scheduling system for open-pit mine transportation is one such much needed application. Traditional open-pit mining systems, which often cause vehicle delays and congestion, are controlled by human authority. The number of sensors has been used to operate unmanned cars in an open-pit mine. The sensors haves been used to prove the real-time data in large quantity. Using this data, we analyses and create an improved transportation scheduling mechanism so as to optimize the paths for the vehicles. Considering the huge amount the data received and aggregated through various sensors or sources like, the GPS data of the unmanned vehicle, the equipment information, an intelligent, and multi-target, open-pit mine unmanned vehicle schedules model was developed. It is also matched with real open-pit mine product to reduce transport costs, overall unmanned vehicle wait times and fluctuation in ore quality. To resolve the issue of scheduling the transportation, we prefer to use algorithms based on artificial intelligence. To improve the convergence, distribution, and diversity of the classic, rapidly non-dominated genetic trial algorithm, to solve limited high-dimensional multi-objective problems, we propose a decomposition-based restricted genetic algorithm for dominance (DBCDP-NSGA-II).

• Applied Chemistry for Engineering
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• v.8 no.3
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• pp.357-364
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• 1997

The objective of this study was to find optimum nonionic surfactants for clean up of soils contaminated by hydrocarbon oils. PIT(phase inversion temperature) measurements in ternary systems containing pure hydrocarbons, pure nonionic surfactants, and water were carried out and interfacial tensions were measured as a function of time for n-hexadecane oil drops brought into contact with various mixtures of nonionic surfactant and water. Batch surfactant washing experiments were performed based on the measurement, results of PIT and interfacial tension and the results showed that maximum removal of n-hexadecane occurred at the PIT of the system. For the $C_{12}E_5(C_{12}H_{25}O(CH_2CH_2O)_5H)$ system, maximum n-hexadecane removal of 73.4% occurred at the PIT of $52^{\circ}C$. In contrast, n-hexadecane removal at $25^{\circ}C$ and at $60^{\circ}C$, each corresponding to the conditions of below PIT and above PIT of the system, was found to be 57.1% and 57.0% respectively. The maximum removal of a hydrocarbon at the PIT of a system, where the hydrophilic and hydrophobic properties are balanced, was found to be due to the existence of high oil solubilization into a middle-phase microemulsion and ultralow interfacial of the order of $10^{-2}$ to $10^{-3}$ dyne/cm between middle-phase microemulsion and excess oil phase.

• Korean Journal of Environmental Biology
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• v.27 no.2
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• pp.146-154
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• 2009

To suggest effective ways of the management of reptiles in Korea national parks, we applied PIT (passive integrated transponder) tag and radio telemetry research methods in the monitoring of reptiles in Odaesan and Woraksan national parks. We implanted PIT tags into 137 snakes (six species) captured in both the national parks between March 2006 and October 2008 and also radio-tracked two Korean rat snakes (Elaphe schrenckii anomala) from September 2007 to November 2008 in the Woraksan national park. Of total 137 snakes which we had inserted the PIT tag, 17 snakes (12.40%) were recaptured. Based on the PIT tag data of the recapture, we successfully obtained the annual growth rate of Korean cat snakes (Elaphe dione) and Red-tongue pit-viper (Gloydius ussuriensis). Home range of the Korean rat snakes based on the data of radiotracking was estimated as 389,600$m^2$ (MCP: Minimum convex polygon) and 471,800$m^2$ (Kernel 95%) for males and 162,500$m^2$ and 208,700$m^2$ for females. These results suggest that if we apply PIT tag and radio telemetry research methods to manage reptiles in Korea national parks, it could greatly increase our understanding about their basic ecology and as the result, it could allow us to develop better management and conservation ways of reptiles in Korea national parks.

• Journal of The Korean Association For Science Education
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• v.27 no.9
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• pp.919-929
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• 2007

Some Korean terminologies related to the structures of vascular tissues in plant morphology, written differently depending upon textbooks and dictionaries, were analysed to propose properly expressed Korean terminologies. A total of 14 university textbooks such as general biology, plant biology, and plant morphology were selected and investigated. The terminologies on the xylem structures, i.e., apotracheal parenchyma, paratracheal parenchyma, tylose, and tangential (longitudinal) section; and on the pit structures i.e., simple pit, bordered pit, aspirated bordered pit, and pit aperture; and on the stelar structures, i.e., haplostele, actinostele, plectostele, and solenostele were examined. The definition and etymology of the terminologies were traced in 4 textbooks of plant anatomy and 2 dictionaries of biology and botany written in English. And then reasonably expressed Korean terminologies, mostly written in Chinese characters, were suggested. The terminologies were compared with those that appeared in the Iwanami dictionary of biology published in Japan. It was expected that the results would contribute to promote mutual understanding between teachers and students in learning plant biology.

• Proceedings of the SCSK Conference
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• 2003.09b
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• pp.392-404
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• 2003

A new technology to achieve o/w microemulsions allows the formulation of transparent products with low surfactant content. The PIT Nanotechnology approach gives cosmetic/pharmaceutical o/w microemulsions in one step with a broad variety of surfactants, cosurfactants and oil phases.

• Journal of dental hygiene science
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• v.15 no.6
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• pp.768-774
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• 2015

The purpose of this study was to grasp the benefits from pit and fissure sealants and to analyze the factors of influencing the benefit amount by using the raw data of the Korea National Health and Nutrition Examination Survey for 2007~2013 targeting the subjects aged from 6 years in full to 18 years. The analysis was used STATA 11.0. As a result of the analysis, the following conclusions were obtained. It rose up to 1.24 pieces after carrying out the national health insurance coverage from averagely 0.93 piece until the year in 2007~2009 (up to November) when is before enforcing the national health insurance coverage in the pit and fissure sealants. The benefits from pit and fissure sealants depending on general characteristics were surveyed to be higher in the higher income level, in the more subscription to health insurance and private insurance, and in the more toothbrushing frequency per day. The factors that have influence upon the benefits from pit and fissure sealants were shown to include whether or not to have the national health insurance coverage in the pit and fissure sealants, income level, health insurance type and private insurance subscription appearance, and one-day toothbrushing frequency. Synthesizing the results, a rise in the benefits from pit and fissure sealants is shown in 2010 based on December 2009 when the national health insurance coverage in the pit and fissure sealants was implemented, but is showing the tendency of declining again from 2011. To increase the benefits from pit and fissure sealants, it is thought that the schemes will need to be discussed such as reinforcing publicity on the national health insurance coverage in the pit and fissure sealants, expanding a support for low-income bracket, and differentiating the outpatient cost sharing according to socio-economic level.

• Journal of Korea Water Resources Association
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• v.43 no.10
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• pp.921-932
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• 2010

In this study, the adjustment processes of the disturbed channels by sand or gravel mining were investigated by a two dimensional numerical model in the generalized coordinate system. As a numerical scheme, the CIP (cubic interpolated pseudoparticle method) method was used to calculate the advection term in the flow field and central difference method was used to the diffusion term in it. The pit of the channel was partially filled with sediment at the toe of the pit upstream. As time increased, the headcut erosion upstream in the pit was decreased due to the sediment inflow. The almost inflow sediment upstream was trapped into the pit and the sediment deposit wedge migrated downstream in the pit with the steep submerged angle of repose. The numerical model was reproduced well the evolution processes of the channel. The mining pit migrated with speed as the channel was steep, and the numerical results were in overall agreement with the experimental results.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.34 no.1
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• pp.21-32
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• 2016

Open-pit mines are the critical infrastructure for acquiring natural resources. Since it could be endangered by environmental and safety problems during operations, continuous monitoring is required for this type of mine. However, the domestic level management and accumulation of present state data of the topographical alteration are incurred by the development and restoration of open-pit mines relying on digital topographic maps and site surveys. Because of it, other than an expert cannot be viewed easily examines those changes information of open-pit mines in the domestic level. If the efficient management and public access of the open-pit mine is targeted, it is easy to build a web-based three-dimensional monitoring system, utilized in the space information software of open source. Therefore, we purposed on developing an open-pit mine monitoring system to support the development and restoration of the ecology-friendly environment, which could be easily monitored by the general public for those changes within terrain and environments due to operations of the mine.