• The Journal of Korean Academy of Prosthodontics
• /
• v.44 no.3
• /
• pp.343-355
• /
• 2006

Statement of problem. The success of osseointegration can be enhanced with an implant that has improved surface characteristics. Anodic oxidation is one of the surface modifying method to achieve osseointegration. Voltage of anodic oxidation can change surface characteristics and cell activity Purpose. This study was performed to evaluate MG63 cell responses such as affinity, proliferation and to compare surface characteristics of anodic oxidized titanium in various voltage. Material and method. The disks for cell culture were fabricated from grade 3 commercially pure titanium,1 m in thickness and 12 mm in diameter. Surfaces of 4 different roughness were prepared. Group 1 had a machined surface, used as control. Group 2 was anodized under 220 V, group 3 was anodized under 300 V and group 4 was anodized under 320 V. The microtopography of specimens was observed by scanning electron microscope (JSM-840A, JEOL, Japan) and atomic force microscope(Autoprobe CP, Park Scientific Instrument, USA). The surface roughness was measured by confocal laser scanning microscope(Pascal, LSM5, Zeiss, Germany). The crystal structure of the titanium surface was analyzed with x-ray diffractometer(D8 advanced, Broker, Germany). MG63 osteoblast-like cells were cultured on these specimens. The cell morpholgy was observed by field emission electron microscope(Hitachi S-4700, Japan). The cell metabolic and proliferative activity was evaluated by MTT assay Results and conclusion. With in limitations of this in vitro study, the following conclusions were drawn. 1. In anodizing titanium surface, we could see pores which did not show in control group. In higher anodizing voltage, pore size was increased. 2. In anodizing titanium surface, we could see anatase. In higher anodizing voltage, thicker oxide layer increased crystallinity(anatase, anatase and rutile mixed). 3. MG63 cells showed more irregular, polarized and polygonal shape and developed more lamellipodi in anodizing group as voltage increased. 4. The activity of cells in MTT assay increased significantly in group 3 and 4 in comparison with group 1 and 2. However, there was no difference between group 3 and 4 at P<0.05. Proliferation of MG63 cells increased significantly in pore size($3-5.5{\mu}m$) of group 3 and 4 in comparison with in pore size($0.2-1{\mu}m$ ) of group 2.

• Journal of the Korea Society of Computer and Information
• /
• v.18 no.3
• /
• pp.107-118
• /
• 2013

In this paper, we developed the semiconductor monitoring system for the etching process. Around the world, expert companies are competing fiercely since the semiconductor industry is a leading value-added industry that produces the essential components of electronic products. As a result, many researches have been conducted in order to improve the quality, productivity, and characteristics of semiconductor products. Process monitoring techniques has an important role to give an equivalent quality and productivity to produce semiconductor. In fact, since the etching process to form a semiconductor circuit causes great damage to the semiconductors, it is very necessary to develop a system for monitoring the process. The proposed monitoring system is mainly focused on the dry etching process using plasma and it provides the detailed observation, analysis and feedback to managers. It has the functionality of setting scenarios to match the process control automatically. In addition, it maximizes the efficiency of process automation. The result can be immediately reflected to the system since it performs real-time monitoring. UI (User Interface) provides managers with diagnosis of the current state in the process. The monitoring system has diverse functionalities to control the process according to the scenario written in advance, to stop the process efficiently and finally to increase production efficiency.

• Clean Technology
• /
• v.23 no.2
• /
• pp.133-139
• /
• 2017

Bio-based plastics containing the biomass content higher than 25 wt% have been considered as environment-friendly materials due to their effects on the reduction in the $CO_2$ emission and petroleum consumption as well as biodegradability after use. In this study, poly vinyl chloride, plant-derived plasticizers, by adding a biodegradable catalyst was observed a change in the biodegradability and physical properties. To produce the oxidative decomposition transparent bio film, which is broken down in the initial percent elongation and physical properties such as tensile strength, it was to test the safety of the product as a food packaging material. Poly vinyl chloride, primary plasticizer, secondary plasticizer, anti fogging agent, the combined stabilizer were mixed in a high speed mixer, then extruded using an extrusion molding machine, after cooling, winding, to produce a oxidative decomposition transparent bio film and the control film, with a thickness of $12{\mu}m$ through winder role. Mechanical properties tensile strength, elongation, and the maximum load elongation and biodegradation test. Transparent bio film produced by biodegradation catalyst is compared with the control film. Tensile strength and elongation of films were found to be no significant difference. Further, as a result of the biodegradation test for 45 days based on the ASTM D6954-04 method, biodegrability of film is 61.4%.

• Journal of Sasang Constitutional Medicine
• /
• v.21 no.1
• /
• pp.237-246
• /
• 2009

1. Objectives To compare the contents of heavy metals, residual pesticides and sulfur dioxide before/after decoction. 2. Methods The heavy metal contents before/after decoction were measured by Inductively Coupled Plasma Atomic Emission Spectrometry (ICP-AES) and mercury analyzer. In order to analyze pesticides in 3 samples we used simultaneous multi-residue analysis of pesticides by GC/ECD, followed by GC/MSD analysis to confirm the identity of the detected pesticide in each sample. In addition, the contents of sulfur dioxide (SO2) were performed by Monier-Williams distillation method. 3. Results 1) The mean values of heavy metal contents (mg/kg) for the samples were as follows: Yuldahanso-tang (before decoction - Pb; 1.85, Cd; 0.148, As; 0.042 and Hg; 0.003, after decoction - Pb; 0.096, Cd; 0.006, As; 0.006 and Hg; 0.002), Chongsimyonja-tang (before decoction - Pb; 1.193, Cd; 0.094, As; 0.084 and Hg; 0.008, after decoction - Pb; 0.053, Cd; 0.007, As; 0.011 and Hg; not detected) and Taeyeumjowee-tang (before decoction - Pb; 0.878, Cd; 0.078, As; 0.302 and Hg; 0.004, after decoction - Pb; 0.079, Cd; 0.005, As; 0.006 and Hg; not dectcted). 2) Contents (mg/kg) of residual pesticides before/after decoction in all samples were not detected. 3) Contents (mg/kg) of sulfur dioxide (SO2) before decoction in Yuldahanso-tang, Chongsimyonja-tang and Taeyeumjowee-tang exhibited 6.1, 37.8, 31.5 and 19.7, respectively. However, contents of sulfur dioxide after decoction in all samples were not detected. 4. Conclusion These results will be used to establish a criterion of heavy metals, residual pesticides and sulfur dioxide.

• Journal of Microbiology and Biotechnology
• /
• v.21 no.9
• /
• pp.893-902
• /
• 2011

Endophytic fungi are little known for their role in gibberellins (GAs) synthesis and abiotic stress resistance in crop plants. We isolated 10 endophytes from the roots of field-grown soybean and screened their culture filtrates (CF) on the GAs biosynthesis mutant rice line - Waito-C. CF bioassay showed that endophyte GMH-1B significantly promoted the growth of Waito-C compared with controls. GMH-1B was identified as Penicillium minioluteum LHL09 on the basis of ITS regions rDNA sequence homology and phylogenetic analyses. GC/MS-SIM analysis of CF of P. minioluteum revealed the presence of bioactive $GA_4$ and $GA_7$. In endophyte-soybean plant interaction, P. minioluteum association significantly promoted growth characteristics (shoot length, shoot fresh and dry biomasses, chlorophyll content, and leaf area) and nitrogen assimilation, with and without sodium chloride (NaCl)-induced salinity (70 and 140 mM) stress, as compared with control. Field-emission scanning electron microcopy showed active colonization of endophyte with host plants before and after stress treatments. In response to salinity stress, low endogenous abscisic acid and high salicylic acid accumulation in endophyte-associated plants elucidated the stress mitigation by P. minioluteum. The endophytic fungal symbiosis of P. minioluteum also increased the daidzein and genistein contents in the soybean as compared with control plants, under salt stress. Thus, P. minioluteum ameliorated the adverse effects of abiotic salinity stress and rescued soybean plant growth by influencing biosynthesis of the plant's hormones and flavonoids.

• Korean Chemical Engineering Research
• /
• v.49 no.4
• /
• pp.423-431
• /
• 2011

Recentincreasing awareness of the environmental damage caused by the $CO_2$ emission of fossil fuelsstimulated the interest in alternative and renewable sources of energy. Fuel cell is a representative example of hydrogen energy utilization. In this study, Molten Carbonate Fuel Cell system is simulated by using $Aspen^{TM}$. Stack model is consisted of equilibrium reaction equations using $ACM^{TM}$(Aspen Custom Modeler). Balance of process of fuel cell system is developed in Aspen $Plus^{TM}$ and simulated at steady-state. Analysis of performance of the system is carried out by using sensitivity analysis tool with main operating parameters such as current density, S/C ratio, and fuel utilization and recycle ratio.In Aspen $Dynamics^{TM}$, dynamics of MCFC system is simulated with PID control loops. From the simulation, we proposed operation range which generated maximum power and efficiency in MCFC power plant.

• Journal of Advanced Marine Engineering and Technology
• /
• v.39 no.4
• /
• pp.412-417
• /
• 2015

The IMO MEPC has been increasingly strengthening the emission standard for marine environment protection. In particular, nitrogen oxide (NOx) emissions of all ocean-going ships built from 2016 will be required to comply with the Tier-III regulation. In this study, a vanadia based SCR (Selective Catalytic Reduction) system developed for ship application was installed on a diesel engine for power generation of the training ship T/S SAENURI in Mokpo National Maritime University. For the present study, the exhaust pipeline of the generator diesel engine was modified to fit the urea SCR system. This study investigated the NOx reduction performance according to the two kind of injection method of urea solution (40%): Auto mode through the PLC (Programable Logic Control) and Manual mode. We were able to find the ammonia slip conditions when in manual mode method. So, the optimal urea injection quantity can be controlled at each engine load (25, 35, 50%) condition. It was achieved 80% reduction on nitrogen oxide. Furthermore, we found that the NOx reduction performance was better with the load up-down (while down to 25% from 50%) than the load down-up (while up to 50% from 25%) test.

• The Journal of The Korea Institute of Intelligent Transport Systems
• /
• v.13 no.3
• /
• pp.10-24
• /
• 2014

Bicycle is a useful transportation mode that is healthy, emission-free, and environmentally compatible. Although large efforts have been made to promote the use of bicycling to date, there still exist various hurdles and limitations. One of the key issues to increase bicycling is how to gather bicycle-related data from the field and to generate valuable information for both users and operations agencies. This study proposes a method to process bicycle trajectory data which is obtained from tracing global positioning systems(GPS) equipped bicycle, which is defined as the probe bicycle. The proposed method is based on the concept of statistical quality control of data. In addition, a data collection and processing scenario in support of public bicycle system is presented. The outcomes of this study would be valuable fundamentals for developing bicycle traffic information systems that is a part of future intelligent transportation systems(ITS).

• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.11 no.7
• /
• pp.2719-2726
• /
• 2010

The purpose of this study was to investigate the scientific basic grounds for the assessment of health and environmental diseases resulting from air pollutants in Pohang. For this study, we investigated pollutants, weather characteristics and concentration distribution of fine particles ($PM_10$) yearly and each season, using data from Air Quality Monitoring Stations. The properties of concentration distribution and seasonal fluctuation of $PM_10$ were studied qualitatively and quantitatively using CALPUFF, air dispersion model. The average concentration of $PM_10$ for each season was spring($75.7{\mu}g/m^3$)>summer($56.8{\mu}g/m^3$)>winter($53.6{\mu}g/m^3$)>fall( $52.7{\mu}g/m^3$). In the case of spring, high concentrations appear due to the Asian dust frequently occurring. The contributions of $PM_10$ classified by the types of pollution source in Pohang were point source 62%>mobile source 33%>area source 5%. An important point is that 97% of emissions were produced from the iron manufacture in steel industry. Therefore, it is necessary to control the emission sources of pollutants and to construct an observation system at Pohang steel industrial complex from now on. It’s time to control the risk factors for health and environmental disease to protect the health of resident in Pohang and its neighboring areas.

• Journal of the Korean Applied Science and Technology
• /
• v.35 no.4
• /
• pp.1349-1358
• /
• 2018

In addition to responding to the environmental pollution caused by fossil fuels, the enforcement of Renewable Fuel Standard(RFS) system has increased the utilization of renewable energy such as refined fuels oil. The by-product fuel oil(No. 2) and the refined fuel oil(reduced-pressure) are strictly regulated by the domestic legislation and the chemical property changes of the refined fuel oil(reduced-pressure) mixed with the by-product fuel oil(No. 2) were analyzed. As a result of analyzing the physical properties of refined fuel oil(reduced pressure) obtained by mixing 1 : 1 of by-product fuel oil(No. 2), it satisfied the quality standards stipulated by the domestic Enforcement Decree of the Wastes Control Act. However, the results of the additional tests related to the fuel showed a high aromatic content. The high content of aromatic in a fuel is likely to cause the soot and ehaust emission gas during the combustion of the used equipment.