• Journal of the Korean Society of Combustion
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• v.12 no.3
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• pp.16-23
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• 2007

Employing an after-treatment system has almost become a mandatory requirement for Diesel vehicles, which results from a reinforced exhaust regulations as the number of vehicles powered by a Diesel engine increases. The Diesel Particulate Filter (DPF) system is considered as one of the most efficient method to reduce particulate matter (PM); however, the improvement of a regeneration performance at any engine operation point presents a considerable challenge by itself. Temperature, gas composition and flow rate of exhaust gas are important parameters in DPF evaluation processes, especially during a regeneration process. Engine dynamometer and segment tester are generally used in DPF evaluation so far. These test methods, however, could not completely evaluate the effect of various parameters on real DPF, such as oxygen concentration, amount of soot and exhaust gas temperatures. The evaluation of DPF systems using a dump combustor has been verified experimentally and this dump combustor system is likely to be appropriate for the DOC (Diesel Oxidation Catalyst) and SCR (Selective Catalytic Reduction) assessments test, too.

• Environmental Engineering Research
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• v.13 no.4
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• pp.177-183
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• 2008

Ex-situ reductive dechlorination of carbon tetrachloride (CT) by iron sulfide in a batch reactor was characterized in this study. Reactor scaled-up by 3.5 L was used to investigate the effect of reductant concentration on removal efficiency and process optimization for ex-situ degradation. The experiment was conducted by using both liquid-phase and gas-phase volume at pH 8.5 in anaerobic condition. For 1 mM of initial CT concentration, the removal of the target compound was 98.9% at 6.0 g/L iron sulfide. Process optimization for ex-situ treatment was performed by checking the effect of transition metal and mixing time on synthesizing iron sulfide solution, and by determining of the regeneration time. The effect of Co(II) as transition metal was shown that the reaction rate was slightly improved but the improvement was not that outstanding. The result of determination on the regeneration time indicated that regenerating reductant capacity after $1^{st}$ treatment of target compound was needed. Due to the high removal rates of CT, ex-situ reductive dechlorination in batch reactor can be used for basic treatment for the chlorinated compounds.

• Korean Journal of Medicinal Crop Science
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• v.12 no.5
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• pp.391-396
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• 2004

Optimal culture conditions for efficient in vitro propagation and polysaccharide production of Orostachys japonicus were established. O. japonicus was cultured in media containing various growth regulators and carbon sources. The highest regeneration rate was achieved in 1.0 and $3.0\;mg\;l\;^{-1}$ of 2,4-D concentration, while the lowest was obtained in $10.0\;mg\;l\;^{-1}$ 2,4-D concentration. When different carbone sources were added in the culture medium, plant growth was high in 3% sucrose treatment. The micropropagated shoots were successfully acclimatized in artificial soils and produced comparable amont of polysaccharide compred to parent cultivated plants.

• Korean Chemical Engineering Research
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• v.43 no.3
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• pp.432-437
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• 2005

An electric swing adsorption (ESA) process for recovering highly pure $CO_2$ from the mixed gases was tested. In this study, activated carbon fibers were used as an adsorbent. The activated carbon fibers showed fast adsorption rate and the high adsorption capacity for $CO_2$ adsorption under the condition of the ambient pressure. Activated carbon fiber with higher specific surface area was suitable to repeated adsorption-desorption cycle process, showing consistent breakthrough curve. Especially, the regeneration method by vacuum combined with ESA improved the performance of desorption process by an additional 17％ regeneration efficiency compared to a vacuum only method, and showed the high regeneration efficiency at comparatively low 7-8 Wh energy.

• Magazine of the Korean Society of Agricultural Engineers
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• v.44 no.2
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• pp.161-173
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• 2002

Recently, absorbent biofilters, which are inexpensive and easy to manacle, have been supplied to the rural areas, but have limitations in removing the nutrients effectively. Accordingly, as an alternative plan. natural zeolites were arranged in front or at the rear of the absorbent biofilters, and their removal efficiency for nitrogen and, ultimately, their applicability to the on-site wastewater treatment system were studied. Furthermore, the same experiments were carried out on artificial zeolites, made from coal ashes at National Honam Agricultural Experiment Station, to compare natural zeolites with artificial ones. Treated wastewater through the Absorbent Biofilter showed 22.6% nitrogen removal efficiency, while 64.6% was attained when natural Zeolites were placed in front of the absorbent biofilters (Zeolite-Aerobic process). As an addition, phosphorus was also efficiently removed. On the other hand, Aerobic-Zeolite process, which arranged natural zeolites at the rear of the biofilters, did not have significantly higher nitrogen removal as compared to the treatment using only the absorbent biofilters. Furthermore, upon regeneration of the natural zeolite, the ion exchange rate was fecund to increase over 10% as compared to before regeneration. Our results show that natural zeolites, applied to the on-site wastewater treatment system through the Zeolite-Aerobic process, not only increase the removal efficiency of nutrients, but, by choosing the appropriate regeneration time, can also be cast-effective. Artificial zeolites, on the other hand, though more efficient in removing nutrients, cannot be regenerated and, therefore, are not cost-effective.

• Journal of Periodontal and Implant Science
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• v.51 no.6
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• pp.433-443
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• 2021

Purpose: This study aimed to evaluate the effectiveness of the partial split-flap technique with a K-incision on vertical guided bone regeneration (vGBR) and to retrospectively analyze the clinical and radiographic outcomes of dental implantation using this approach. Methods: In total, 78 patients who received 104 dental implants with vGBR, categorized as (1) pre-GBR and post-implantation and (2) simultaneous GBR and implantation, were enrolled. Data analysis was based on periapical radiographs, clinical photos, and dental records. The 2-sample t-test was used to compare the 2 surgical procedures. Results: The baseline vertical bone level, augmented bone height (ABH), and treatment duration were significantly higher in the pre-GBR procedure group. The survival rates of the implants were 96.1% and 94.8% in implant- and patient-based analyses, respectively. In Cox regression analysis, high rates of implant failure were found in the presence of ABH of ≥4 mm, smoking, and diabetes. Conclusions: Within the limitations of this retrospective study, the partial split-flap technique using a K-incision for vGBR showed stable clinical outcomes and favorable dental implant survival.

• Journal of Biomedical Engineering Research
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• v.43 no.4
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• pp.230-240
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• 2022

Drug regeneration technology is an efficient strategy than the existing new drug development process, which requires large costs and time by using drugs that have already been proven safe. In this study, we recognize the importance of the new drug regeneration aspect of new drug development and research in predicting functional similarities through the basic molecular structure that forms drugs. We test four string-based algorithms by using SMILES data and searching for their similarities. And by using the ATC codes, pair them with functional similarities, which we compare and validate to select the optimal model. We confirmed that the higher the molecular structure similarity, the higher the ATC code matching rate. We suggest the possibility of additional potency of random drugs, which can be predicted through data that give information on drugs with high molecular similarities. This model has the advantage of being a great combination with additional data, so we look forward to using this model in future research.

• Journal of The Korean Society of Grassland and Forage Science
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• v.19 no.1
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• pp.23-30
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• 1999

The conditions for callus formation and plant regeneration were confirmed in four varieties of alfalfa(Medicago sativa L.). Among four varieties of alfalfa, "Vernal" expressed the highest rate for both of callus formation and plant regeneration. Otherwise, among SH(Schenk and Hildebrandt), MS(Murachige and Skoog) and N6 medium (Chu), SH medium was highest degree of efficiencies respectively in callus formatio and plant regeneration. In this study, we determined volume of hormones and other compounds appended in media. For callus formation, only $3mg/{\ell}$ of 2,4-D (2,4-dichlorophenoxy acetic acid) was appended in their media. For plant regeneration, the three kinds of media were used; the medium appended $5mg/{\ell}$ of NAA (1-naphtalene acetic acid) and $2mg/{\ell}$ of kinetin (6-furfurylaminopurine), the medium appended $11mg/{\ell}$ of 2,4-D and $1mg/{\ell}$ of kinetin, and the medium appended $1.6g/{\ell}$ of ammonium sulfate and $5.75g/{\ell}$ of proline. We obtained alfalfa plants from callus by regeneration, about sixty five days later transfer calli to regeneration media.

• Korean Journal of Plant Resources
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• v.24 no.5
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• pp.628-635
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• 2011

This study was conducted to establish the tissue culture system for Korean domestic Miscanthus sinensis, which is used in various purposes such as forage, and bio-energy resources. With the mature seed of Miscanthus, optimum concentrations of plant growth regulators were identified for an efficient callus induction and regeneration. Among the treatments of 1~10 $mg{\cdot}L^{-1}$ 2,4-D, IBA, or NAA, callus induction rate was highest (85.3%) on MS medium containing 5 $mg{\cdot}L^{-1}$ 2,4-D. Under the condition, the callus were efficiently induced and proliferated with comparably lower frequencies of callus browning. In shoot regeneration, the treatment of NAA combined with BAP seemed to contribute more efficient conditions to shoot regeneration than those of NAA with Kinetin or 2-iP. Especially, regeneration efficiency and number of regenerated plants were 83.7% and 5.5 in 3 $mg{\cdot}L^{-1}$ NAA with 5 $mg{\cdot}L^{-1}$ BAP, respectively, which were higher frequencies than those in NAA with Kinetin or 2-iP. In results, 5 $mg{\cdot}L^{-1}$ 2,4-D and 3 $mg{\cdot}L^{-1}$ NAA combined with 5 $mg{\cdot}L^{-1}$ BAP were efficient for embryogenic callus induction and regeneration of Miscanthus. This system would be useful for mass-propagation and developing new cultivars via tissue culture of Miscanthus sinensis.

• Journal of Periodontal and Implant Science
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• v.35 no.1
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• pp.235-250
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• 2005

The current interest in periodontal tissue regeneration has lead to research in bone graft, root surface treatments, guided-tissue regeneration, administration of growth factors, and the use of enamel matrix protein as possible means of regenerating lost periodontal tissue. Several studies have shown that a strong correlation between platelet-rich plasma and the stimulation of remodeling and remineralization of grafted bone exits, resulting in a possible increase of 15-30% in the density of bone trabeculae. The purpose of this study was to study the histopathological results and differences between the use of platelet-rich plasma and the use of enamel matrix $protein(Emdogain^?)$ about bone regeneration at the implant. Implant fixtures were inserted and graft materials placed into the left femur in the experimental group, while the only implant fixtures placed in the control group. In the first experimental group, platelet-rich plasma and xenograft were placed at the supracrestally placed implant site, and in the second experimental group, $Emdogain^{(R)}$ and xenograft placed at the supracrestally placed fixture site. The degree of bone regeneration adjacent to the implant fixture was observed and compared histopathologically at 2, 4, and 8 weeks after implant fixture insertion. The results of the experiment are as follows: 1. The rate of osseointegration to the fixture threads was found to be greater in the experimental group compared to in the control group. 2. The histopathological findings showed that the bone regeneration, the partial osseointegration existed at 4 weeks, and that osseointegration and bone density increaced in the experimental groups at 8 weeks. 3. The results showed that new bone formation and bone remodeling increased in the area near to the fixture in the first and second experimental groups at 8 weeks than at 4 weeks. The results showed that in the area distant from the fixture, new bone formation did not increase and bone remodeling decreased in the first experimental group at 4, 8 weeks, and that new bone formation increased in the second experimental group. 4. The histopathological findings showed that AZ deposition in the first experimental group was remarkable at 2, 8 weeks, and in the second experimental group at 2, 4, 8 weeks in the area distant from the fixture threads.