• 한국화재소방학회논문지
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• 제32권5호
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• pp.57-66
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• 2018

29명이 사망하고 40명이 부상을 입은 제천 스포츠센터 화재 사례에 대해 다수 사상자가 발생한 원인을 초기대응과 관리적인 측면을 중심으로 분석하였다. 초기대응 측면은 119신고 지연, 2층 세신사 비상구로 피난유도를 하지 않음, 1층과 3층 비상계단쪽 방화문 개방 상태 유지, 3층 주계단실 쪽 방화문 닫지 않음, 비상방송을 하지 않음으로 분석하였다. 관리적인 측면은 1층의 스프링클러설비 알람밸브 폐쇄, 소방펌프 제어반에서 기동 정지 위치에 놓음, 주차장 반자 안 누수 및 누전 방치, 2층 여탕의 휴게실 피난구유도등이 가려져 있고 비상구에 물건이 적치됨, 2층 자동문의 조작버튼 불량상태로 방치, 형식적인 소방안전관리, 소방시설 부실한 자체점검, 방화셔터와 배연창 미작동으로 분석하였다.

• Journal of Periodontal and Implant Science
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• 제30권4호
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• pp.803-814
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• 2000

Current acceptable methods of promoting periodontal regeneration are basis of removal of diseased soft tissue, root treatment, guided tissue regeneration, graft materials, biological mediators. Platelet Rich Plasma have been reported as a biological mediator which regulate activities of wound healing progress including cell proliferation, migration, and metabolism. The purpose of this study is to evaluate the possibility of using the Platelet Rich Plasma as a regeneration promoting agent for furcation involvement defect. Five adult beagle dogs were used in this experiment. With intrasulcular and crestal incision, mucoperiosteal flap was elevated. Following decortication with 1/2 high speed round bur, degree II furcation defect was made on mandibular third(P3), forth(P4) and fifth(P5) premolar. 2 month later experimental group were PRP plus bovine bone and bovine bone only. After 4, 8 weeks, the animals were sacrificed by perfusion technique. Tissue block was excised including the tooth and prepared for light microscope with Gomori's trichrome staining. At 4 weeks after surgery, there were rapid osteogenesis phenomenon on the defected area of the Platelet Rich Plasma plus bovine bone group and early trabeculation pattern was made with new osteoid tissue produced by activated osteoblast. Bone formation was almost completed to the fornix of furcation by 4 weeks after surgery. In conclusion, Platelet Rich Plasma can promote rapid osteogenesis during early stage of periodontal tissue regeneration.

• Journal of the Optical Society of Korea
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• 제14권3호
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• pp.235-239
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• 2010

In this study, we have fabricated two types of non-invasive fiber-optic respiration sensors that can measure respiratory signals during magnetic resonance (MR) image acquisition. One is a nasal-cavity attached sensor that can measure the temperature variation of air-flow using a thermochromic pigment. The other is an abdomen attached sensor that can measure the abdominal circumference change using a sensing part composed of polymethyl-methacrylate (PMMA) tubes, a mirror and a spring. We have measured modulated light guided to detectors in the MRI control room via optical fibers due to the respiratory movements of the patient in the MR room, and the respiratory signals of the fiber-optic respiration sensors are compared with those of the BIOPAC$^{(R)}$ system. We have verified that respiratory signals can be obtained without deteriorating the MR image. It is anticipated that the proposed fiber-optic respiration sensors would be highly suitable for respiratory monitoring during surgical procedures performed inside an MRI system.

• 대한치과보철학회지
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• 제30권3호
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• pp.361-378
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• 1992

The purpose of this investigation was to evaluate the effect of the porous hydroxyapatite particles (Interpore $200^{(R)}$) and guided tissue regeneration membrane ($Gore-Tex^{TM}$ augmentation material) on amount and shape of generating new bone adjacent to implant. Implants were placed immediately after extraction in the bilateral 3rd, 4th premolars of the mandible of the adult dogs. In all experimental groups, artificial bony defects were formed at the buccal cortex area, 3.3mm in width and 3.0mm in depth. In the control group : sutured without HA particles & membranes after placing implants, the experimental group 1 : membrane was place over the artificial bony defect, the experimental group 2 : bony defect was filled with HA particles and covered with membrane. The examination of bone-implant interfaces using light microscope and fluorescent microscope concluded as follows. 1. In all three experimental groups, osseointegration was observed without epithelial migration. 2. In the healing degree of bony defect area, the experimental group 1, 2 showed more prominent healing than control group, and the experimental group 1 showed the most excellent bone formation. 3. In fluorescent microscopic finding, bone remodeling was observed in regenerated bone tissue at defect area of experimental group 1, but in experimental group 2, irregular, discontinuous linear fluorescence was observed at the lower portion of defect area and sign of bone remodeling was weak.

• 한국추진공학회지
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• 제18권5호
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• pp.43-53
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• 2014

충격파 터널은 초음속 및 극초음속 비행조건의 유동장을 지상에서 가장 유사하게 모사할 수 있는 시험설비로서, 거의 반세기 동안 전 세계적으로 유용하게 운용되고 있다. 국내의 극초음속 비행체에 대한 많은 관심의 결과로 충격파 시험장치에 대해 주목하고 있으며, 최근에 KAIST에서는 중간 크기의 충격파 터널을 갖추게 되었다. 본 논문은 개발된 충격파 터널의 성능과 최근 수행된 모델 스크램제트 시험자료를 제시하고 있다. 본 연구에서 모사된 자유흐름 유동조건은 마하수 5.7 비행속도에 해당하며, 이러한 비행조건에서 스크램제트의 초음속 연소기내에 유동 환경을 모사하였다.

• 한국추진공학회지
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• 제25권2호
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• pp.119-143
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• 2021

최근 발사체 개발의 큰 흐름을 살펴보면, 친환경, 저비용, 재사용, 심우주 탐사를 위한 저장성, 외부행성에서의 추진제 확보 가능성 등의 이유로 액체 메탄이 로켓 연료로 각광 받기 시작했다. 재사용 발사체 기술의 보편화, 국제적인 엔진개발 추세에 발맞춰 미래의 경쟁력과 임무 유연성을 확보하려면 엔진 개발 기간 등을 고려해서 가능한 빨리 메탄엔진 개발을 추진해야 하며, 제작 및 시험 인프라, 활용성, 개발 비용 등을 종합적으로 고려하면 부스터 엔진보다 저추력 엔진을 선행 개발하는 것이 더 적절한 것으로 판단된다.

• 한국전자통신학회논문지
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• 제16권6호
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• pp.1019-1028
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• 2021

가스 센서, 조도 센서, 온도 센서, 아두이노 우노, 블루투스 모듈을 이용하여 화재 발생 시 비상구 위치를 신속하게 파악하기 위해 비상구 유도등을 설계하고 제작하였다. 본 연구는 화재 발생 시 가스 센서와 온도 센서를 이용하여 높은 온도와 연기를 감지하였을 때 시인성을 좋게 하기 위하여 조도 값이 낮을수록 적색 화살표, 조도 값이 높을수록 녹색 화살표가 나오도록 설계하였다. 또한 통신 모듈을 이용한 경보음과 문자전송 알고리즘을 응용하여 174Hz의 경보음과 화재 장소를 알리는 문자메시지를 소방서로 송신하는 기능을 추가하여 보다 큰 화재를 예방할 수 있게 설계되었다.

• Journal of Periodontal and Implant Science
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• 제26권1호
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• pp.47-67
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• 1996

The purpose of this study was to observe the effect of $Biocoral^R$ graft and bioglass 45S5 graft in combination with ePTFE membrane in periodontal osseous defects for new bone formation. Nine healthy dogs were used. Under general anesthesia, 3-wall defects were created on the mesial and distal surfaces of the maxillary right canines, the mesials of the maxillary right second premolars, the distals of the mandibular right canines and the mesials of the mandibular right third premolars. To induce periodontitis, a silicone rubber, $Provil^R$ light body, was injected under pressure into the defects. Ninety days later, $Provil^R$was removed and followed by thorough root planing. The followings were then applied in the mesial and distal defects of the maxillary right canines, the mesials of the maxillary right second premolars, the distals of the mandibular right canines and the mesials of the mandibular right third premolars by random selections : 1) ePTFE membrane only application, 2) $Biocoral^R$ graft, 3) $Biocoral^R$ graft and ePTFE membrane application, 4)Bioglass 45S5 graft, 5) Bioglass 45S5 graft and ePTFE membrane application. The membranes were removed 1 month later. The dogs were sacrified at 1, 2 and 3 months following the graft, and block sections were made, demineralized, embedded, stained and examined by light microscope and transmission electron microscope. On the sections from teeth treated with ePTFE membrane only, the defect demonstrated extensive connnective tissue and alveolar bone regeneration. The $Biocoral^R$ graft group demonstrated extensive bone regeneration compared with ePTFE membrane only group. In the $Biocoral^R$ graft plus ePTFE membrane group, regeneration of new alveolus and crest occurred within the defect. As the experimental period lengthened, bone regeneration was increased and bone bridge was formed among the graft particles. The but bioglass 45S5 graft group demonstrated extensive bone regeneration but the amount of new bone was less than that of the $Biocoral^R$ graft group. For the bioglass 45S5 graft plus ePTFE membrane group, the amount of new bone was also increased. As the experimental period lengthened, bone regeneration was increased. Multinucleated giant cells, fibroblasts and macrophages were observed. As the bone formation was increased, the number of such cells was decreased. In conclusion, the $Biocoral^R$ was found better than the bioglass 45S5 for new bone formation, and the use of ePTFE membrane alone or with $Biocoral^R$/bioglass 45S5 can be supported as potential methods of promoting bone formation.

• Nuclear Engineering and Technology
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• 제54권3호
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• pp.842-848
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• 2022

Parametric studies of heat transfer and fluid flow are very important research of interest because the design and operation of fluid flow and heat transfer systems are guided by these parametric studies. The safety of the system operation and system optimization can be determined by decreasing or increasing particular fluid flow and heat transfer parameter while keeping other parameters constant. The parameters that can be varied in order to determine safe and optimized system include system pressure, mass flow rate, heat flux and coolant inlet temperature among other parameters. The fluid flow and heat transfer systems can also be enhanced by the presence of or without the presence of particular effects including gravity effect among others. The advanced Generation IV reactors to be deployed for large electricity production, have proven to be more thermally efficient (approximately 45% thermal efficiency) than the current light water reactors with a thermal efficiency of approximately 33 ℃. SCWR is one of the Generation IV reactors intended for electricity generation. High Performance Light Water Reactor (HPLWR) is a SCWR type which is under consideration in this study. One-eighth of a proposed fuel assembly design for HPLWR consisting of 7 fuel/rod bundles with 9 coolant sub-channels was the geometry considered in this study to examine the effects of system pressure and mass flow rate on wall and fluid temperatures. Gravity effect on wall and fluid temperatures were also examined on this one-eighth fuel assembly geometry. Computational Fluid Dynamics (CFD) code, STAR-CCM+, was used to obtain the results of the numerical simulations. Based on the parametric analysis carried out, sub-channel 4 performed better in terms of heat transfer because temperatures predicted in sub-channel 9 (corner subchannel) were higher than the ones obtained in sub-channel 4 (central sub-channel). The influence of system mass flow rate, pressure and gravity seem similar in both sub-channels 4 and 9 with temperature distributions higher in sub-channel 9 than in sub-channel 4. In most of the cases considered, temperature distributions (for both fluid and wall) obtained at 25 MPa are higher than those obtained at 23 MPa, temperature distributions obtained at 601.2 kg/h are higher than those obtained at 561.2 kg/h, and temperature distributions obtained without gravity effect are higher than those obtained with gravity effect. The results show that effects of system pressure, mass flowrate and gravity on fluid flow and heat transfer are significant and therefore parametric studies need to be performed to determine safe and optimum operating conditions of fluid flow and heat transfer systems.

• Radiation Oncology Journal
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• 제27권1호
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• pp.42-48
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• 2009

목적: 영상유도방사선치료(IGRT)와 호흡동조방사선치료(4DRT)의 도입은 치료계획 및 치료부위 확인에서 환자에게 방사선 조사량을 증가시킬 가능성이 있다. 따라서 IGRT/4DRT용 영상장비와 기존 장비에서 영상선량을 측정 및 비교하였다. 대상 및 방법: IGRT 및 4DRT를 위해 새로이 도입된 4DCT (GE, Ultra Light Speed 16)와 모의치료기(Varian Acuity), 그리고 치료기(Varian IX)에 장착된 kVp (OBI)의 영상장비 및 EPID (aSi 1000)를 대상으로, RANDO 팬톰의 표면 선량을 측정하여 기존의 장비들(single slice CT (GE, Light Speed), 모의치료기(Varian, Ximatron), L-gram (Varian 2100C))과 비교하였다. 측정은 열형광선량계를 이용하여 두뇌부, 눈, 갑상선, 흉부, 복부 및 골반부의 표면에서 측정하였다. 결과: 기존 CT와 비교하여 4DCT모드에서는 흉부와 복부에서 10배 이상의 선량증가를 보였다($1.74{\pm}0.34$ vs $23.23{\pm}3.67$ cGy). Acuity에서의 선량은 모든 측정부위에서 Ximatron보다 감소하였다($0.91{\pm}0.89$ vs $6.77{\pm}3.56$ cGy). EPID는 기존 L-gram 선량의 약 50% ($1.83{\pm}0.36$ vs $3.80{\pm}1.67$ cGy)였다. OBI의 투시영상선량은 $0.97{\pm}0.34$ cGy며, CBCT 선량은 $2.3{\pm}0.67$ cGy였다. 결론: 4DCT가 선량증가의 가장 큰 원인이며, OBI와 CBCT에 의한 선량은 적으나 매번 치료에 적용 시 총 선량 증가에 대한 고려가 필요하다.