• 한국구조물진단유지관리공학회 논문집
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• 제8권2호
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• pp.177-183
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• 2004

적산온도은 시멘트 수화의 결과로서 시간이 경과함에 따라 콘크리트 강도가 얻어진다는 것으로 콘크리트의 강도는 시멘트의 수화반응과 관계가 있다. 시멘트의 수화반응은 온도와 경과시간에 큰 영향을 받는다. 따라서 본 연구에서는 콘크리트 강도예측에 있어서 양생시간과 온도의 함수인 적산온도와 고강도콘크리트 강도의 상관성을 검토하고자 하였다.

• Carbon letters
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• 제28권
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• pp.66-71
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• 2018

To improve the flame retardant performance of cellulose fibers, fluorine functional groups were introduced under various controlled fluorination conditions. The properties of the fluorinated cellulose fibers were analyzed by X-ray photoelectron spectroscopy and a thermogravimetric analysis. The fluorine functional group content in the fluorinated cellulose fibers increased with an increase in the fluorination temperature. However, the fluorination reaction increased the char yield and decreased the rate of degradation of the cellulose fibers by introducing donors, enabling the formation of a thick and compact char layer. Therefore, the flame retardant properties of cellulose fibers were improved following the fluorination treatment.

• 제어로봇시스템학회논문지
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• 제22권3호
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• pp.171-176
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• 2016

In this paper, we consider a regulation problem of nonlinear systems under two triangular conditions where there possibly exist unbounded parameters in the systems. We propose a state feedback controller with dynamic gains in order to deal with unbounded parameters based on the condition of the time-varying rate of the growing parameter. The analysis of our control scheme is carried out by Lyapunov stability method. Our control method is verified by simulation results.

• 한국수소및신에너지학회논문집
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• 제15권3호
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• pp.228-234
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• 2004

It was discussed about explosion danger of hydrogen gas experimentally that could be happen during the handling and using. Hydrogen concentration was varied from 10 to 60 vol% for get the explosion characteristics of hydrogen and 5 kinds of cylindrical vessel were used to find the explosion characteristics of hydrogen according to the vessel volume. Initial pressure of hydrogen-air mixture was varied from 0.6 to 2 kg/cm2. Based on the experiment, explosion pressure was most high near the 30vol% of hydrogen and explosion pressure was increased slightly according to the increase of vessel volume but explosion pressure rise rate was decreased. Explosion pressure was increased linearly proportional to the initial pressure of gas mixture.

• 설비공학논문집
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• 제28권12호
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• pp.489-494
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• 2016

There have been many cases when an air curtain installed in the apartment could not remove the gases well, such as carbon dioxide and particles like as smoke, oils, and vapors generated during cooking to disperse pollutants into the room. This study used a numerical analysis to show how the pollutant-removing performance of the range hood is changed when the air curtain is installed front of the kitchen table. The result of this study was that when the air amount supplied by an air curtain through the slot was about 50% of the exhaust amount, the capturing efficiency of the range hood for pollutants increased 90% more than without an air curtain. Even when the amount of supplied air was small, the capturing efficiency improved markedly with the use of an upward air curtain. In case that the air flow rate of the slot was greater than 60%, the capturing efficiency decreased.

• 한국화재소방학회논문지
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• 제25권5호
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• pp.21-31
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• 2011

병원 밖에서 발생한 비외상성 심정지 환자에 대한 119 구급대원의 처치 현황과 개선방안을 연구하기 위해 대전충남에 근무하는 119 구급대원 322명에게 설문을 실시하였다. 119 구급대원들은 병원전 비외상성 심정지 환자에 대해 CPR은 96.9%(309명), AED는 53%(169명)에서 거의 매번 또는 매번 실시한다고 하였다. 1급 응급구조사와 간호사의 경우 IV는 94.7%(143명)에서 가끔 실시하거나 실시한 적이 없다고 하였고 약물처치의 경우도 90.7%(136명)에서 실시한 적이 없다고 응답하였다. AED, 기도확보 및 IV 를 실시하지 못했던 이유에 대해서는 구급인원이 부족하고, 시간이 부족하며, 흔들리는 구급차 때문이라는 의견이 많았다. 임상실습이나 병원실습의 경험이 있는 119 구급대원이 IV나 약물처치를 더 자주 실시하는 것으로 나타났다. 결론적으로, 심정지 환자의 소생률을 향상시키기 위해서는 구급차에 탑승하는 구급인원을 보강하고, 일반인들도 할 수 있는 기본심폐소생술 처치에서 더 나아가 전문심장소생술을 실시할 수 있도록 1급 응급구조사에게 에피네프린의 사용을 허가하며, 임상실기 교육을 강화하고 구급대원을 법적으로 보호할 수 있는 방안이 마련되어야 할 것이다.

• 한국안전학회지
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• 제20권3호
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• pp.71-77
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• 2005

This study aims to find the safe vent area to prevent a destruction of building by gas explosion in a building. Explosion vessel which used in this experiment is 1/5 scale down model of simple livingroom and its dimension is 100cm in length 60cm in width and 45cm in height. Liquified petroleum gas(LPG) was injected to the vessel to the concentration of 4.5vol%, and injection rate were varied in 1L/min or 4L/min. Gas mixture was ignited by the 10kV electric spark. For analysis the characteristics of vented explosion pressure according to the vent size and vent shape, its size and shape were varied. From the experiment, it was found that explosion pressure in the vented explosion :in affected by the gas injection rate, vent area and vent shape. And the vent area to volume ratio(S/V) to prevent the building destruction by explosion pressure, it is recommended that the design of vent area happened by the explosion should be above 1/500cm in S/V. And if the vent area has complicate structure in same area, vented explosion pressure will be higher than a single vent, and possibility of building destruction will increase. Therefore to effectively vent the explosion pressure for protect a building and residents from the gas explosion hazards, the same vent area should have a singular and constant shape in the cross-sectional area of the vessel.

• 전기전자학회논문지
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• 제22권4호
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• pp.959-964
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• 2018

본 연구에서는 LED 광시스템과 식물생장제어시스템을 연계하여 센서를 이용하여 식물환경을 제어 가능한 모니터링시스템에 대한 연구이다. 시스템의 성능을 검증하기 위해 에너지효율, data 전송률, 광량제어 특성에 대한 실험을 실시하였다. 실험한 결과 에너지 효율은 80%이상, 무선통신속도가 1Mb/sec이고 광량제어를 5단계이상 조절 가능함으로써 만족한 결과를 얻었다. 제안된 시스템은 LED 식물공장설비에 적용가능하며, 향후 상용화를 위해서는 생산효율 및 노동비 절감을 위한 자동시스템을 구성하여 농업 자동화설비에 기여할 것이다.

• 한국지열·수열에너지학회논문집
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• 제17권2호
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• pp.20-29
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• 2021

In this study, it is proposed that an analysis method using charatersistics curve of PICV in the CFD simulation for hydronic system. From the results, the pressure drop characteristics appeared in the region of PICV at a specified flow rate. And the CFD results are in good agreement with the experimental results. Proposed analysis method is proved that the characteristics of PICV applied to the hydronic system were properly applied in the flow analysis. This result can be applied to PICV in the complex hydronic systems. Therefore, the optimal selection of PICV in hydronic system contribute the building energy saving.

• 공업화학
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• 제24권6호
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• pp.616-620
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• 2013

본 연구에서는 자원 재활용-에너지에 바탕을 둔 돈분, 계분, 혼합물의 연소특성에 대하여 고찰하였다. 시험편은 건조 오븐을 이용하여 항량까지 건조시킨 후에, 콘칼로리미터(ISO 5660-1)를 이용하여 연소성질을 시험하였다. 그 결과 돈분의 최대유효연소열(78.72 MJ/kg)은 계분(69.41 MJ/kg)과 비교하여 탄화수소의 많은 양 때문에 비교적 증가했다. 또한 돈분의 $CO_2$ 발생속도(0.1959 g/s)와 총연기발생률($419m^2/m^2$)도 각각에 대하여 계분보다 증가하였다. 반면에 계분의 CO 발생량(0.0996 kg/kg)과 CO 발생속도(0.0034 g/s)는 계분이 함유하고 있는 많은 무기물 함량 때문에 각각 돈분보다 높았다. 따라서 높은 연소 에너지는 탄화수소 함량에 의존하여 발생되는 것으로 판단된다.