• Restorative Dentistry and Endodontics
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• 제35권1호
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• pp.1-4
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• 2010

감염근관에서의 주치근단 파일의 크기는 학자들마다 많은 논란이 되고 있지만 최근 여러 연구 결과들은 감염근관의 효과적인 세정을 위해서는 근단부 확대 크기가 증가해야 함을 보여주고 있다. 따라서 임상가는 감염근관의 치료 시 새로운 개념에 맞는 치료 전략을 가지고 근관치료에 임해야 한다.

• 천문학회보
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• 제36권1호
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• pp.41.2-41.2
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• 2011

P/2010 A2, a main-belt asteroid having comet-like dust trail was discovered in January 2010, but the origin of the trail is controversial. Moreno et al. (2010) reported water-ice sublimation as a mechanism for the comet-like activity, whereas other researches (Jewitt et al. 2010; Snodgrass et al. 2010) stated that impact collision contributed to the dust trail. For asteroids are categorized based on spectral shape, optical observation using different color filters makes it possible to determine the taxonomic type of P/2010 A2 nucleus, thus gives an answer to the question of activation mechanism of the object. In this presentation, we report multiband observation of P/2010 A2 in January and March 2010 with 1-meter telescope of Ishigaki-Jima Astronomical Observatory. We employed three broadband filters of g', Rc, and Ic. In this presentation, we focus on the data acquisition, the reduction and the derivation of the reflectance spectrum of debris in the trail. Finally we discuss the potential cause of dust ejection from this asteroid.

• 천문학회보
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• 제46권2호
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• pp.56.3-56.3
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• 2021

In a ΛCDM universe, most galaxies are believed to evolve by mergers and accretions. The debris resulting from such processes remains faint and/or diffuse structures, such as tidal streams and stellar halos. Although these structures are a good indicator of the recent mass assembly history of galaxies, they have the disadvantage of being difficult to observe due to their low surface brightness (LSB). To recover these LSB features by reducing the photometric uncertainties introduced by the optics system, we attempt to develop an optimized telescope, called a linear astigmatism free-three mirror system, that minimizes the loss and scattering of light within the telescope. With that prototype, we observe NGC 5907, known as a nearby galaxy with a fabulous loop structure(s), to inspect its performance. After a dedicated data reduction process, including flat-fielding with dark sky flat and sky subtraction, our observation reaches a 1σ surface brightness limit of μlim,r ≃ 28.3 mag arcsec-2 in 10×10 arcsec boxes. We finally identify a single tidal stream that is likely the remnant of a nearly disrupted galaxy. This finding emphasizes that the capability of LSB detection with our telescope is comparable to that of much larger telescopes.

• 한국지반환경공학회 논문집
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• 제15권6호
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• pp.67-73
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• 2014

토석류를 포함하는 산사태 재해는 우리나라에서 그 발생빈도가 상대적으로 큰 자연재해 중 하나이며 이로 인한 인명 및 재산피해는 매년 증가하고 있다. 이에 정부에서는 사면재해 대응 및 예방을 위한 다양한 방지대책을 추진하고 있으나, 대부분 재해발생 이후 발생지역을 중심으로 복구대책을 수립하는 것이 대부분이라 실질적인 국민의 생명과 재산을 보호하는 예방대책이라고 보기는 어렵다. 이에 본 연구는 산사태 재해 예방을 목적으로 실제 지형의 특성을 파악, 이를 위험도 평가에 활용하는 방안에 대해 알아보고자 하였다. 지형특성 분석을 위해 SINMAP(Stability INdex MAPping)과 통계적 기법인 벡터 분산을 활용하였으며 이를 실제 산사태 발생현장에 적용, 지형특성과 산사태와의 관계를 규명하고자 하였다. 분석결과는 제안한 두 가지 기법이 동일하게 위험도가 높다고 평가한 지역에서는 산사태 위험도가 상대적으로 높게 산정되었다. 이는 본 연구에서 제시한 방법이 지형특성과 산사태 위험도와의 관계성 규명에 있어 합리적임을 보여준다고 할 수 있다. 또한 실제 현장조사 결과와 비교한 산사태 위험도는 SINMAP 기법이 토석류와 같은 연속성 산사태에 있어 보다 정확하게 판단되었으나 특정요소의 위험성을 구체적으로 고려할 수 있는 기법을 추가적으로 고려한다면 보다 정확한 산사태 위험을 평가할 수 있을 것으로 사료된다.

• 국제학술발표논문집
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• The 6th International Conference on Construction Engineering and Project Management
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• pp.54-55
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• 2015

Increase of impervious areas due to expansion of housing area, commercial and business building of urban is resulting in property change of stormwater runoff. Also, rapid urbanization and heavy rain due to climate change lead to urban flood and debris flow damage. In 2010 and 2011, Seoul had experienced shocking flooding damages by heavy rain. All these have led to increased interest in applying LID and decentralized rainwater management as a means of urban hydrologic cycle restoration and Natural Disaster Prevention such as flooding and so on. Urban development is a cause of expansion of impervious area. It reduces infiltration of rain water and may increase runoff volume from storms. Low Impact Development (LID) methods is to mimic the predevelopment site hydrology by using site design techniques that store, infiltrate, evaporate, detain runoff, and reduction flooding. Use of these techniques helps to reduce off-site runoff and ensure adequate groundwater recharge. The contents of this paper include a hydrologic analysis on a site and an evaluation of flooding reduction effect of LID practice facilities planned on the site. The region of this Case study is LID Rainwater Management Demonstration District in A-new town and P-new town, Korea. LID Practice facilities were designed on the area of rainwater management demonstration district in new town. We performed analysis of reduction effect about flood discharge. SWMM5 has been developed as a model to analyze the hydrologic impacts of LID facilities. For this study, we used weather data for around 38 years from January 1973 to August 2014 collected from the new town City Observatory near the district. Using the weather data, we performed continuous simulation of urban runoff in order to analyze impacts on the Stream from the development of the district and the installation of LID facilities. This is a new approach to stormwater management system which is different from existing end-of-pipe type management system. We suggest that LID should be discussed as a efficient method of urban disasters and climate change control in future land use, sewer and stormwater management planning.

• 대한두개안면성형외과학회지
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• 제17권1호
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• pp.1-4
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• 2016

Absorbable plates are used widely for fixation of facial bone fractures. Compared to conventional titanium plating systems, absorbable plates have many favorable traits. They are not palpable after plate absorption, which obviates the need for plate removal. Absorbable plate-related infections are relatively uncommon at less than 5% of patients undergoing fixation of facial bone fractures. The plates are made from a mixture of poly-L-lactic acid and poly-DL-lactic acid or poly-DL-lactic acid and polyglycolic acid, and the ratio of these biodegradable polymers is used to control the longevity of the plates. Degradation rate of absorbable plate is closely related to the chance of infection. Low degradation is associated with increased accumulation of plate debris, which in turn can increase the chance of infection. Predisposing factors for absorbable plate-related infection include the presence of maxillary sinusitis, plate proximity to incision site, and use of tobacco and significant amount of alcohol. Using short screws in fixating maxillary fracture accompanied maxillary sinusitis will increase the rate of infection. Avoiding fixating plates near the incision site will also minimize infection. Close observation until complete absorption of the plate is crucial, especially those who are smokers or heavy alcoholics. The management of plate infection is varied depending on the clinical situation. Severe infections require plate removal. Wound culture and radiologic exam are essential in treatment planning.

• 한국응용곤충학회지
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• 제19권3호
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• pp.135-140
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• 1980

참깨종자의 종자전염균을 조사아던중, 우리나라에서는 미기록인 Macrophomina phaseolina가 12개 sample중 7개 sample에서 검출되었다. 본 균의 종자 종자상에서의 생육상 및 병자각과 병포자의 형태를 기술하였다. 본 균의 병자각형성에는 광선이 필순조건이었으나 PDA나 OA배지상에서는 병자각이 형성되지 않았고 물한천잎배지상에서 병자각이 많이 형성되었다. 본 균은 참깨종자의 심한 발아저해와 입고가 원인이 되었고 감자괴경에 탄부병징을 나타내었다. 목 균은 월동후의 참깨식물의 잔재와 포장의 이병유균에서도 검출되었다.

• Maxillofacial Plastic and Reconstructive Surgery
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• 제23권5호
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• pp.471-477
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• 2001

Failure to use effective methods of reduction, fixation, and immobilization may lead to nonunion with osteomyelitis, owing to the compound nature of most fractures of the mandible. Nonunion results in fibrous pseudoarthrosis at the fracture site with instability that, once formed, does not improve spontaneously. Once the nonunion with osteomyelitis secondary to fractures has become established, intermaxillary fixation and drainage of infected tissue should be instituted as early as possible, because the fixation & drainage enhances the patient comfort and hinders ingress of microorganisms & debris by movement of bone fragments. The authors treated three cases of nonunion with osteomyelitis by intermaxillary fixation, incision & persistent drainage on the previous fistula site and endodontic drainage of infected teeth in the fracture site of mandible. The localization & sequestration of the infected bone around the fracture was better performed persistently by natural homeostatic mechanism in $8{\sim}10$ weeks and the bony union was then attained without bone grafting.

• Journal of Periodontal and Implant Science
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• 제25권1호
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• pp.24-34
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• 1995

The purpose of this study was to compare effects of demineralization of citric acid and tetracycline HCI on periodontally involved root surface. Twelve periodontally involved single rooted teeth were used. After scaling and root planing, root conditioning with citric acid and tetracycline HCI were carried and the teeth were processed scanning electron microscopic observation.The results were as follows: The scaled root surface was covered by much debris and calculus. The effect of demineralization of citric acid and tetracycline HCI was more reduced on scaling group than root planing group, because of hypermineralization of cementum surface and demineralization effect on root surface of tetracycline HCI showed tendency to reduction. The root planed group displayed more smooth root surface than scaling group, the surface was covered by smear layer, thus no exposure of dentinal tubule opening and collagen fiber, especially after root planing, citric acid and tetracycline HCl treated group showed exposure of dentinal tubule and collagen fiber, thus it was thought that new connective tissue attachment could be acquired.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2001년도 하계학술대회 논문집
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• pp.652-655
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• 2001

In this paper, I have studied minimization of the kerf-width and surface burning which are occurred after the singulation process of multi layer $\mu$-BGA( thickness 1.1 mm, 0.9 mm) with a pulsed Nd:YAG( = 532 nm, repetition rate = 10 Hz) laser. The thermal energy of a pulsed Nd:YAG laser is used to cut the copper layer. I have studied are minimization of the surface burning and kerf-width using a photo resist, $N_2$blowing and polyester double sided tape as a cutting parameter. The $N_2$blowing reduces a laser energy loss by debris and suppresses a surface carbonization. Also, I have studied characters of cutting with a choice of side of laser beam incidence. The SEM(Scanning Electron Microscope), non-contact 3D inspector and high-resolution microscope are used to measure kerf width and surface state. The optimum value of 1.1 mm $\mu$-BGA singulation is 524 $\mu$m that is reduced kerf width of 60 % with $N_2$blowing. And I obtained reduction of carbonization of 68 % with a polyester double side tape in 0.9 mm $\mu$-BGA. I used laser intensity of 1.91$\times$10$^{6}$ / $\textrm{cm}^2$ in this study.