• 구강회복응용과학지
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• 제37권3호
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• pp.171-176
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• 2021

종격동기종은 치과 영역에서 매우 드물고 잠재적으로 위험한 합병증이다. 이의 흔한 원인으로는 핸드피스와 고압 공기/물 주사기를 사용하는 발치, 근관치료, 잇몸 밑 치은연하 소파술 등이 있다. 본 증례는 임플란트 식립을 위한 전 치료로 주사기를 이용하여 상악동에 골이식을 시행받은 61세 여자에게서 발생한 대량의 종격동기종과 피하기종의 증례이다. 환자는 치료 도중 갑작스럽게 발생한 구강 통증과 함께 의식 소실이 발생하였고, 응급실로 전원 되었다. 영상학적 검사상 종격동기종과 함께 얼굴과 목부위 전체에 피하기종이 발견되었다. 예방적 항생제, 산소 흡입, 금식 등의 보존적 치료가 이루어졌고, 합병증 없이 7일 만에 퇴원하였다. 환자의 실신은 시술 중 상악동 천공 후 과량의 공기유입으로 인해 발생한 종격동기종에 의해 순간적인 강한 흉부 압박으로 혈압 감소와 통증 쇽에 의한 것으로 생각된다. 치과 치료 중 환자가 의식을 잃었다면 기도 폐쇄의 위험성이 있기 때문에 종격동기종을 즉각적으로 감별하고 치료해야 한다.

• 한국화재소방학회논문지
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• 제22권3호
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• pp.194-200
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• 2008

고층건물에서 급기가압 제연시스템과 같이 연기제어를 위해 제연구역에서의 압력차를 이용하는 제연시스템을 성공적으로 설계하고 운영하기 위해서는 건물내 압력형성에 영향을 미치는 건축적 요인들을 검토해야 하며 그중 큰 영향을 발휘하는 요인이 연돌효과이다. 본 연구에서는 고충건물의 피난환경과 제연시스템에 대해 연돌효과가 미치는 영향을 검토하기 위해서 여름과 겨울철에 각각국내 고층건물을 대상으로 급기가압 제연시스템을 가동하면서 피난계단, 부속실 및 거실에서의 압력변화를 측정하고 분석하였다. 연돌효과의 영향이 커지는 겨울철의 경우 급기가압 제연시스템이 가동되면 부속실에서 계단쪽으로의 누기현상과 연돌효과가 합쳐지면서 고층부의 계단실내 압력이 크게 상승하여 재실자가 대피를 위해 피난문을 열고자 할 때 문제가 발생할 수 있다.

• 한국화재소방학회논문지
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• 제22권3호
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• pp.216-220
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• 2008

물분무소화설비는 화원의 냉각, 주변공기의 희석, 미세한 물방울의 증발에 의한 열차단과 같은 소화특성을 이용한다. 미분무수의 운동량은 입자가 큰 물방울에 비해 상대적으로 낮으며 화원의 침투능력도 효과적이지 못하다. 증발된 수증기에 의한 기여는 무게가 가볍고 밀도가 희박하여 화원에 일부분으로 제한되는 경향이 있다. 반면, 사이클식 미분무 패턴은 성층화된 분무 특성에 의해 공기 추출능력과 침투력이 개선될 것으로 예상된다. 이 논문에서는 유체공학적 화재모델인 FDS를 사용하여 교번식 미분무 패턴에 대해 분석된 소화능력을 다룬다. 저자는 이 분석이 미분무 노즐의 표본을 개발하기 위한 기본 개념을 제공할 수 있기를 기대한다.

• Strategy21
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• 통권40호
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• pp.82-114
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• 2016

The purpose of this article is to analyze the progress of North Korea's SLBM threat, and to assess the technological capacity and threat level of its SLBMs. Currently, North Korea has approximately 1000 ballistic missiles, such as the SCUD, Musudan, and Nodong, in stock. This article pays close attention to the background and strategical implication behind North Korea's obsession with developing SLBMs despite possessing sufficient means to launch provocations with its current arsenal of ground based ballistic missiles and conventional weapons. Based on the abovementioned analysis, this article will recommend possible response directions for the ROK Armed Forces to North Korea's SLBM threat. It is highly difficult to detect SLBMs due to its stealthy nature, as it is launched underwater after covert infiltration. North Korea's SLBM is considered a game changer in that even one SLBM can significantly change the strategic balance of North East Asia. North Korea's SLBM test launch in August has made a 500km flight, landing 80km inside the JADIZ (Japan Air Defense Identification Zone), and as such, it is assessed that North Korea already possesses underwater ejection and cold launch capabilities. The most realistic response to North Korea's imminent SLBM threat is bolstering anti-submarine capabilities. ROK Armed Forces need to upgrade its underwater kill-chain by modernizing and introducing new airborne anti-submarine assets and nuclear-powered submarines, among many options. Moreover, we should integrate SM-3 missiles with the Aegis Combat system that possess strong detection capabilities and flexibility, thereby establishing a sea-based Ballistic Missle Defense (BMD) system centered around the Aegis Combat System, as sea-based ballistic missile threats are best countered out in the seas. Finally, the capabilities gap that could arise as a result of budgetary concerns and timing of fielding new assets should be filled by establishing firm ROK-US-Japan combined defense posture.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2016년도 제50회 동계 정기학술대회 초록집
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• pp.150-150
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• 2016

Mankind is enjoying a great convenience of their life by the rapid growth of secondary industry since the Industrial Revolution and it is possible due to the invention of huge power such as engine. The automobile which plays the important role of industrial development and human movement is powered by the Engine Module, and especially Diesel engine is widely used because of mechanical durability and energy efficiency. The main work mechanism of the Diesel engine is composed of inhalation of the organic material (coal, oil, etc.), combustion, explosion and exhaust Cycle process then the carbon compound emissions during the last exhaust process are essential which is known as the major causes of air pollution issues in recent years. In particular, COx, called carbon oxide compound which is composed of a very small size of the particles from several ten to hundred nano meter and they exist as a suspension in the atmosphere. These Diesel particles can be accumulated at the respiratory organs and cause many serious diseases. In order to compensate for the weak point of such a Diesel Engine, the DPF(Diesel Particulate Filter) post-cleaning equipment has been used and it mainly consists of ceramic materials(SiC, Cordierite etc) because of the necessity for the engine system durability on the exposure of high temperature, high pressure and chemical harsh environmental. Ceramic Material filter, but it remains a lot of problems yet, such as limitations of collecting very small particles below micro size, high cost due to difficulties of manufacturing process and low fuel consumption efficiency due to back pressure increase by the small pore structure. This study is to test the possibility of new structure by direct infiltration of SiC Whisker on Carbon felt as the next generation filter and this new filter is expected to improve the above various problems of the Ceramic DPF currently in use and reduction of the cost simultaneously. In this experiment, non-catalytic VS CVD (Vapor-Solid Chemical Vaporized Deposition) system was adopted to keep high mechanical properties of SiC and MTS (Methyl-Trichloro-Silane) gas used as source and H2 gas used as dilute gas. From this, the suitable whisker growth for high performance filter was observed depending on each deposition conditions change (input gas ratio, temperature, mass flow rate etc.).

• 한국지반환경공학회 논문집
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• 제8권6호
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• pp.5-12
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• 2007

이암은 건조 조건에서는 일정한 강도와 강성을 가지나, 지하수 침투 등에 의한 습윤, 포화 시 고유의 강도 및 강성이 저하되어 급속히 풍화되는 특성을 가지며, 포항지역에서 자주 발생하는 절취사면의 활동은 주로 이암이 풍화되어 전단강도가 급격히 저하되는 것으로 볼 수 있다. 본 연구는 시추조사시 강성이 충분한 것으로 평가된 이암층에 PRD강관말뚝을 시공한 후 정재하 시험을 실시한 결과 소요지지력이 부족하여, 이를 보강하기 위한 가장 우수한 방법을 찾기 위하여 여러 가지 공법을 검토하였다. 말뚝지지력 증대에 가장 효과적인 방법을 찾기 위해 말뚝주변 및 선단부에 MSG공법, 마이크로파일 보강후 주변그라우팅공법, 선단보강 그라우팅 및 콘크리트 속채움 등의 방법으로 시험시공을 실시하였고, 시험말뚝에 대한 정재하시험 결과 MSG공법으로 보강한 말뚝의 지지력이 가장 우수함을 알 수 있었다.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1991년도 하계학술대회 논문집
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• pp.753-756
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• 1991

This paper aimed to analyse dose sensitivity to the controllable parameters of in-door radon $(^{222}Rn)$ and its decay products(Rn-D) by applying the input-output linear system theory. Physical behaviors of $^{222}Rn$ & Rn-D were analyzed in terms of $^{222}Rn$ gas generation, -migation and - infiltration to indoor environments, and the performance output-function(i.e. mean dose equivalent to Tracho-Bronchial(TB) lung region was assessed to the following ranges of the controllable parameters; a) the ventilation rate constant $({\lambda}_v)$ : $0{\sun}500[h^{-1}]$. b) the attachment rate constant$({\lambda}_a)$ : 0-500 $[h^{-1}]$. c) deposition rate constant $({\lambda}{_{d}^{u}})$: 0-50$[h^{-1}]$. A linear input-output model was reconstructed from the original models in literatures, as follows, which was modified into the matrices consisting of 111 nodal equations. a) indoor ${222}Rn$ & Rn-D Behaviour: jacobi- Porstendorfer- Bruno model. b) lung dosimerty : Jacobi-Eisfeld model. Some of the major findings, which identify the effectiveness of this model, were as follows. a) ${\lambda}_v$ is most effective, dominant controllable parameters in dose reduction, if mechanical ventilation is applied. b) ${\lambda}_v$, depending on the air particle-concentration, reduces the dose somewhat within ${\lambda}_v$<1 $h^{-1}R range. However, the dose increases conversely, ${\lambda}_v$>1 $h^{-1}R range range. c) ${\lambda}{_{d}^{4}}$ reduces the dose linearly as ${\lambda}_v$ dose. Such dose(z-axis) sentivities are shown with three-dimensional plots whoes x,y-axes are combined 2out the 3 parameter${\lambda}_v{\lambda}_s,\;{\lambda}_d^s$.

• 한국화재소방학회논문지
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• 제22권4호
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• pp.20-26
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• 2008

최근 급증하고 있는 초고층건축물의 건립에 있어 건축법에서 규정하는 자연제연방식인 배연창이 바람의 영향과 함께 연돌효과에 미치는 영향을 네트워크 모델인 CONTAMW을 통해 분석하였다. 초고층건축물에서 연돌효과는 배연창 개방 및 외기풍속에 따라 중성대의 위치형성에 중요한 영향을 주는 것으로 나타났다. 배연창 개방은 중성대를 개방층 쪽으로 이동시켰으며, 외기풍속의 영향은 중성대를 고층부로 상향이동시키는 것으로 분석되었다. 또한, 화재조건에서 바람의 영향을 고려하지 않을 경우 화재실의 부력 및 팽창으로 실내공기가 배출되는 정상적으로 배연성능을 보였으나, 바람의 영향을 고려할 경우 외기풍속이 빠를수록 화재실의 부력 및 팽창보다 바람의 영향이 크게 작용하여 오히려 외기가 유입되는 비정상적인 배연성능을 나타낼 수 있음을 확인하였다.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2010년도 제39회 하계학술대회 초록집
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• pp.281-281
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• 2010

Very low refractive index (<1.4) materials have been proved to be the key factor improving the performance of various optical components, such as reflectors, filters, photonic crystals, LEDs, and solar cell. Highly porous SiO2 are logically designed for ultralow refractive index materials because of the direct relation between porosity and index of refraction. Among them, ordered macroporous SiO2 is of potential material since their theoretically low refractive index ~1.10. However, in the conventional synthesis of ordered macroporous SiO2, the time required for the crystallization of organic nanoparticles, such as polystyrene (PS), from colloidal solution into well ordered template is typical long (several days for 1 cm substrate) due to the low interaction between particles and particle - substrate. In this study, polystyrene - polyacrylic acid (PS-AA) nanoparticles synthesized by miniemulsion polymerization method have hydrophilic polyacrylic acid tails on the surface of particles which increase the interaction between particle and with substrate giving rise to the formation of PS-AA film by simply spin - coating method. Less ordered with controlled thickness films of PS-AA on silicon wafer were successfully fabricated by changing the spinning speed or concentration of colloidal solution, as confirmed by FE-SEM. Based on these template films, a series of macroporous SiO2 films whose thicknesses varied from 300nm to ~1000nm were fabricated either by conventional sol - gel infiltration or gas phase deposition followed by thermal removal of organic template. Formations of SiO2 films consist of interconnected air balls with size ~100 nm were confirmed by FE-SEM and TEM. These highly porous SiO2 show very low refractive indices (<1.18) over a wide range of wavelength (from 200 to 1000nm) as shown by SE measurement. Refraction indices of SiO2 films at 633nm reported here are of ~1.10 which, to our best knowledge, are among the lowest values having been announced.

• 한국농공학회지
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• 제33권2호
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• pp.120-129
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• 1991

This study refers to temporal variation of physical properties of tilled soil under natural rainfalls. Field measurements of porosity, average hydraulic conductivity and average capillary pressure head on a tilled soil were conducted by soil sampler and air-entry permeameter respectively at regular intervals after tillage. Temporal variation of these physical properties were analysed by cumulative rainfall energy since tillage. Field experiment was conducted on a sandy loam soil at Suwon durging April~July in 1989. The followings are a summary of this study results ; 1. Average porosity just after tillage was 0.548cm$^3$/cm$^3$. As cumulative rainfall energy were increased in 0.1070, 0.1755, 0.3849 J/cm$^2$, average porosity were decreased in 0.506, 0.4]95, 0.468m$^3$/cm$^3$ respectively. 2. Average hydraulic conductivity just after tillage was 45.42cm/hr. As cumulative rainfall energy were increased in 0.1755, 0.2466, 0.2978, 0.3849J/cm$^2$ average hydraulic conductivity were decreased in 15.34, 13.47, 9.58, 8.65cm/hr respectively. 3. As average porosity were decreased in 0.548, 0.506, 0.495, 0.468cm$^3$/cm$^3$ average capillary pressure head were increased in 6.1, 6.7, 6.9, 7.4cm respectively. 4. It was found that temporal variation of porosity, average hydraulic conductivity on a tilled soil might be expressed as a function of cumulative rainfall energy and average capillary pressure head might be expressed as a function of porosity. 5. The results of this study may be helpful to predict infiltration into a tilled soil more accurately by considering Temporal variation of physical properties of soil.