• 스마트미디어저널
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• 제10권4호
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• pp.35-44
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• 2021

최근 국가적으로 수도권광역급행철도 공사가 진행되고 있다. 도심 내의 터널 굴착공사 시 진동, 소음이 발생하며 이로 인한 인근 거주자에 불편한 영향을 미칠 수 있다. 이와 같은 상황을 대비하고자 건설사는 공사계획단계에서부터 인근지역의 주민들과의 협의, 제기된 민원에 대한 대응방안 수립 등으로 현장내 소음 및 진동 관리계획을 수립한다. 그러나 소음 및 진동 관리계획수립에도 불구하고, 공사기간 동안 산발적으로 발생하는 소음과 진동으로 인해 민원이 근본적으로 해결되지 못하고 있다. 이와 같은 문제점을 해결하기 위해서 프로젝트 계획단계에서부터 인근지역 주민들 대상으로 현실과 몰입감이 높은 소음 및 진동 시뮬레이션 기술을 제공하는 것이 하나의 해결책일 수 있다. 따라서 본 연구는 현실감과 몰입감을 높일 수 있는 가상현실을 기반으로 발파소음 및 진동을 직접 체험할 수 있는 시뮬레이션 시스템 개발의 필요성을 인지하고 개발에 앞서 시스템 사용의 용이성 및 편이성을 고려한 UI를 설계하고자 한다. 본 연구 결과는 향후 가상현실 기반 발파소음 및 진동 시뮬레이션 개발에 기여할 것으로 사료하며, 최종 결과물은 도심 내의 터널 굴착공사계획 수립 및 민원대응에 효과적일 것으로 예상된다.

• Journal of Periodontal and Implant Science
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• 제43권6호
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• pp.301-307
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• 2013

Purpose: This in vitro study was performed to assess the adherence of Porphyromonas gingivalis to a resorbable blast media (RBM) titanium surface pretreated with an ultrasonic scaler or toothbrush and to evaluate the effects of the treatment of the RBM titanium discs on the bacterial removal efficiency of brushing by crystal violet assay and scanning electron microscopy. Methods: RBM titanium discs were pretreated with one of several ultrasonic scaler tips or cleaned with a toothbrush. Then the titanium discs were incubated with P. gingivalis and the quantity of adherent bacteria was compared. The disc surfaces incubated with bacteria were brushed with a toothbrush with dentifrice. Bacteria remaining on the disc surfaces were quantified. Results: A change in morphology of the surface of the RBM titanium discs after different treatments was noted. There were no significant differences in the adherence of bacteria on the pretreated discs according to the treatment modality. Pretreatment with various instruments did not produce significant differences in the bacterial removal efficiency of brushing with dentifrice. Conclusions: Within the limits of this study, various types of mechanical instrumentation were shown to cause mechanical changes on the RBM titanium surface but did not show a significant influence on the adherence of bacteria and removal efficiency of brushing.

• Journal of Korean Dental Science
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• 제9권1호
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• pp.19-27
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• 2016

Purpose: Laser treatment has become a popular method in implant dentistry, and lasers have been used for the decontamination of implant surfaces when treating peri-implantitis. This study was performed to evaluate the effects of an Erbium-doped:Yttrium-Aluminum-Garnet (Er:YAG) laser with different settings on machined (MA), sand-blasted and acid-etched (SA), and resorbable blast media (RBM) titanium surfaces using scanning electron microscopy and confocal microscopy. Materials and Methods: Four MA, four SA, and four RBM discs were either irradiated at 40 mJ/20 Hz, 90 mJ/20 Hz, or 40 mJ/25 Hz for 2 minutes. The specimens were evaluated with scanning electron microscopy and confocal microscopy. Result: The untreated MA surface demonstrated uniform roughness with circumferential machining marks, and depressions were observed after laser treatment. The untreated SA surface demonstrated a rough surface with sharp spikes and deep pits, and the laser produced noticeable changes on the SA titanium surfaces with melting and fusion. The untreated RBM surface demonstrated a rough surface with irregular indentation, and treatment with the laser produced changes on the RBM titanium surfaces. The Er:YAG laser produced significant changes on the roughness parameters, including arithmetic mean height of the surface (Sa) and maximum height of the surface (Sz), of the MA and SA surfaces. However, the Er:YAG laser did not produce notable changes on the roughness parameters, such as Sa and Sz, of the RBM surfaces. Conclusion: This study evaluated the effects of an Er:YAG laser on MA, SA, and RBM titanium discs using confocal microscopy and scanning electron microscopy. Treatment with the laser produced significant changes in the roughness of MA and SA surfaces, but the roughness parameters of the RBM discs were not significantly changed. Further research is needed to evaluate the efficiency of the Er:YAG laser in removing the contaminants, adhering bacteria, and the effects of treatment on cellular attachment, proliferation, and differentiation.

• 스마트미디어저널
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• 제12권11호
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• pp.67-76
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• 2023

본 논문에서는 도심지 지하 발파에 대한 영향 분석을 효율적으로 하기 위해 터널 굴착 시 발파영향에 대해 계측데이터와 연계하여 3차원 BIM 모델 데이터를 작성한 후 인프라 전체의 상호 영향을 고려한 시각화 방안을 제안한다. 이를 위해 시각화에 필요한 BIM 모델링 수준을 정의하였고 GTX-A구간 대상으로 진동계측 데이터 수집, 지형 및 구조물 BIM 작성, 발파진동추정식을 활용한 계측데이터 시각화 방식을 개발하였다. 발파영향원 시각화를 위해 구 형태의 발파영향원 라이브러를 개발하였고 Revit Dynamo 자동화 로직 연동이 가능한 제원표를 구성하였으며 이를 통해 발파진동 영향분석을 3차원으로 쉽게 시각화 하는 방안을 제시하였다. 텍스트 중심의 발파진동 영향분석을 3D로 시각화된 입체적인 방식으로 검토할 수 있어 발파진동 설계 및 민원대응에 용이할 것으로 판단된다.

• Journal of Periodontal and Implant Science
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• 제53권6호
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• pp.444-452
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• 2023

Purpose: The aim of this study was to retrospectively evaluate the survival and failure rates of RESTORE^® implants over a follow-up period of 10-15 years at a university dental hospital and to investigate the factors affecting the survival rate of these dental implants. Methods: A total of 247 RESTORE^® dental implants with a resorbable blast media (RBM) surface inserted in 86 patients between March 2006 and April 2011 at the Department of Periodontology of Seoul National University Dental Hospital were included. Patients with follow-up periods of less than 10 years were excluded, and data analysis was conducted based on dental records and radiographs. Results: Over a 10- to 15-year period, the cumulative survival rate of the implants was 92.5%. Seventeen implants (6.88%) were explanted due to implant fracture (n=10, 4.05%), peri-implantitis (n=6, 2.43%), and screw fracture (n=1, 0.4%). The results of univariate regression analysis using a Cox proportional hazards model demonstrated that implants placed in male patients (hazard ratio [HR], 4.542; 95% confidence interval [CI], 1.305-15.807; P=0.017) and implants that supported removable prostheses (HR, 15.498; 95% CI, 3.105-77.357; P=0.001) showed statistically significant associations with implant failure. Conclusions: Within the limitations of this retrospective study, the RESTORE^® dental implant with an RBM surface has a favorable survival rate with stable clinical outcomes.

• The Plant Pathology Journal
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• 제36권4호
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• pp.314-322
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• 2020

Interplay between histone acetylation and deacetylation is one of the key components in epigenetic regulation of transcription. Here we report the requirement of MoHDA1-mediated histone deacetylation during asexual development and pathogenesis for the rice blast fungus, Magnaporthe oryzae. Structural similarity and phylogenetic analysis suggested that MoHDA1 is an ortholog of Saccharomyces cerevisiae Hda1, which is a representative member of class II histone deacetylases. Targeted deletion of MoHDA1 caused a little decrease in radial growth and large reduction in asexual sporulation. Comparison of acetylation levels for H3K9 and H3K14 showed that lack of MoHDA1 gene led to significant increase in H3K9 and H3K14 acetylation level, compared to the wild-type and complementation strain, confirming that it is a bona fide histone deacetylase. Expression analysis on some of the key genes involved in asexual reproduction under sporulation-promoting condition showed almost no differences among strains, except for MoCON6 gene, which was up-regulated more than 6-fold in the mutant than wild-type. Although the deletion mutant displayed little defects in germination and subsequent appressorium formation, the mutant was compromised in its ability to cause disease. Wound-inoculation showed that the mutant is impaired in invasive growth as well. We found that the mutant was defective in appressorium-mediated penetration of host, but did not lose the ability to grow on the media containing H₂O₂. Taken together, our data suggest that MoHDA1-dependent histone deacetylation is important for efficient asexual development and infection of host plants in M. oryzae.

• 한국자원식물학회지
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• 제31권6호
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• pp.695-703
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• 2018

Previously, we have reported a plant extract isolated from Lysimachia foenum gracum Herba as a new environment friendly biopesticide that has the mycelial growth inhibition effect on Magnaporthe oryzae, the pathogenic fungus of the rice blast disease. For the finding of additional biopesticide candidate, we tested the mycelial growth inhibitory effects about 700 species of plant extracts on PDA media. Among them, the extract of Anemarrhena asphodeloides showed prominent inhibitory effect of which $IC_{50}$ was $139.7{\mu}g/ml$. Mycelial radii of M. oryzae were measured on PDA medium containing the four organic solvent fractions isolated from total extract from A. asphodeloides. Ethyl acetate fraction showed the impressive inhibitory effect of $IC_{50}$, $54.12{\mu}g/ml$. In the subsequent rice field test for the total extract of A. asphodeloides, we obtained encouraging 62.0% control rate of rice blast disease without any phytotoxicity. It is almost equivalent to that of chemical pesticides implying the applicability of the extract as a new biopesticide. In further study, the analysis of active ingredients of the extract would be necessary for the development of a new biopesticide and for the verification of cellular mechanism by which the mycelial growth of M. oryzae inhibited.

• 한국지반공학회지:지반
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• 제13권1호
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• pp.5-18
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• 1997

일반적으로 포화지반의 동적거동을 정확히 예편하기 위해서는 다공성(multi-phase) 재료모델과 그 모델을 이용하는 수치해석 프로그램의 개발이 필요하다. 본 논문에서는 높은 동하중을 받는 다공질 재료의 이론적인 거동해석 연구결과와 함께 기존 MPDAP(multi-phase dynamic analysis program)에 JWL(Jones-Withins-Lee) 모델을 삽입시켜 개발한 MPDAP에 대해 다루었다. JWL모델은 기존 모델과는 달리 폭약의 종류 및 특성 등을 고려할 수 있는 모델이다. 또한 본 논문에서는 개발된 프로그램의 적합성을 조사하기 위하여 몇몇 예제에 대한 검증해석을 수행하였다. 검증결과, 단일매체 (single-phase medium)에서의 탄성구형파의 전파특성 해석의 경우 해석결과와 이론해는 거의 일치하는 결과를 나타내었고, 일차원 선형 압밀해석의 경우과잉 간극수압은 Terzaghi의 이론해와 해석된 결과가 비교적 일치하는 경향성을 보여 주었다. 또한 포화지반에서의 평면 압축파 해석의 경우도 해석결과와 이미 검증된 프로그램 또는 완전해의 해석결과는 거의 유사하게 나타나는 것을 알 수 있었다.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2004년도 추계학술대회
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• pp.1184-1189
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• 2004

Coking process is the thermal decomposition of bituminous coal with final temperature of about $900^{\circ}C$ Because coke plays important roles in ironmaking process in a blast furnace it's essential for developing modeling of coke oven. In this study, An unsteady 2-dimesional model is proposed to simulate coking process in a coke oven. In this model, gas and solid phase are assumed homogeneous continnum and solid bed is assumed as porous media . The model contains governing equations for the solid phase and the gas phase. Complicated phenomena such as swelling, softening, resolidification and shrinkage are neglected and mass loss by drying and devolatilization is reflected by generation of internal pores. Drying, devolatilization, heat transfer and generation of internal pores are also reflected in source terms. Calulated results are compared with experimental data

• Advances in environmental research
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• 제8권1호
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• pp.55-69
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• 2019

The generation of ferrous slag, an industrial by-product from the iron ore industry, results in serious environmental problems. The chemical compositions indicate 30-34% SiO₂, 30-34% CaO, 18-22% Al₂O₃ and 0.5-0.6% Fe₂O₃. The specific gravity, moisture content and pH are in the range of 1.3-1.65, 9.1-10% and 8.5-9.0 respectively. The major part of the slag is composed of sand-size particles. The problems of disposal of slag could be minimized by considering its use in various environmental engineering applications providing additional value to the by-product. This paper mainly focuses on the potential utilization and valorisation of ferrous slag in both water and wastewater treatments. It is effective for the treatment of water and wastewater containing nutrients, heavy metals and polluted river/stormwater.