• 대한설비공학회:학술대회논문집
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• 대한설비공학회 2008년도 하계학술발표대회 논문집
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• pp.1273-1278
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• 2008

A sea water source cascade heat pump was designed and tested in this study. The system was designed to perform a single stage operation in summer, as well as a cascade operation in winter to ensure the high temperature lift. A steady-state simulation model was developed to analyze and optimize its performance. The simulation results show that the R717 exhibits best performance among combinations considered in this study. A R410A also exhibits the highest performance among HFCs with the smallest compressor displacement. A 15-RT R410A-R134a pilot system was installed in the 5-story commercial building at Samcheok City by the East Sea. A scroll type R410A compressor, a reciprocating type R134a compressor, plate type condenser/ evaporator/ cascade heat exchanger and two electronic expansion valves were used to build a pilot. A titanium plate type heat exchanger is also used for the heat exchanging with a sea water. The heat source/sink water is supplied from the well below the seashore in the depth of 5 m. In the initial test of the system, supply water temperature was rising up to $67^{\circ}C$ using a sea water heat source of $9^{\circ}C$, while an ambient temperature was $4.5^{\circ}C$.

• 수산해양교육연구
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• 제18권2호
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• pp.77-84
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• 2006

This research evaluates thermal comfort by comparing the case of maintain cooing temperature of room with the case of raising it at the point of time that human body begins to adapt. An experiment uses constant temperature & humidity chamber 2 places. Pretesting room make up summer season environment, the testing room control by air-conditioner. In condition that maintain temperature of $33^{\circ}C$. The subjects stay in the pretesting room during the 30 minute for the heat storage amount of the normal summertime. The subjects stay in the testing room under each case (case 1: maintaining $24^{\circ}C$, case 2: maintaining $26^{\circ}C$, case 3: up $1^{\circ}C$ after maintaining $24^{\circ}C$ during 30 minute, case 4: up $1^{\circ}C$ after maintaining $26^{\circ}C$ during 40 minute). 1. Result of comparison of case 1 and case 2 appears that thermal sensitive vote examine from slight cool to cool and thermal comfort examine slight comfort by temperature rise at human body adaptation point of time.2. Test of case 3 and case 4 appear similar value at thermal sensitive vote and thermal comfort.3. Through the case 2 and case 4, continuous thermal comfort maintain at $24^{\circ}C$, if raise $26^{\circ}C$, same thermal comfort maintain after a human body adaptation temperature rising effect bring energy saving.

• 한국연소학회지
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• 제22권2호
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• pp.36-41
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• 2017

Aero gas turbine engines must demonstrate their ability to be ignited on ground conditions or relighted in flight. The electric spark ignition is usually used in current aero gas turbine engines. Experiments on ignition characteristics relating to spark igniter penetration depth under atmospheric pressure and temperature conditions were conducted on the model combustor which is scaled in 1/18. Exciter was operated during 2 seconds, and successful ignition phenomena were confirmed by the pressure rising sharply in combustor. In addition, instantaneous ignition images were captured by a high-speed camera. It showed kernel propagation and successful ignition events in the sector model combustor. Ignition test results showed that ignition limit with increase in penetration depth of the igniter plug was wider. When the penetration depth of the igniter plug increased under the same fuel injection pressure condition, successful ignition events were obtained in higher differential pressure conditions between inlet and outlet of the combustor. The results demonstrate that the ratio of the combustible mixture, which is exposed to the high temperature environment around the igniter plug tip, increases. Thereby affect the combustor ignition performance.

• 한국가스학회지
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• 제20권1호
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• pp.46-51
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• 2016

산업용플라스틱의 열분해 및 연소시 연소가스 배출 특성을 알아보기 위하여 유해가스 측정 장치를 이용하여 분석하였다. 첫 번째 결과로써 PC의 경우 열분해는 $400{\sim}450^{\circ}C$에서 분해가 진행되어 약 $608^{\circ}C$에서 연소가 진행되는 것으로 나타났다. 이 때 연소 전까지의 중량감소 속도는 0.03g/min이었다. 둘째 PET의 경우는 PC와 유사하게 $420^{\circ}C$에서 분해가 시작하여 $620^{\circ}C$에서 완료가 되는 것으로 나타났고, 연소 전 중량감소 속도는 0.044g/min인 것을 보였다. PET의 온도 상승에 따른 열분해속도는 염료가 첨가되어있는 경우 열분해속도가 느려지고 분해온도가 높아졌다.

• Computers and Concrete
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• 제12권3호
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• pp.337-349
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• 2013

Traditional concrete is effectively an insulator in the dry state. However, conductive concrete can attain relatively high conductivity by adding a certain amount of electronically conductive components in the regular concrete matrix. The main purpose of this study is to investigate the electrical and thermal properties of conductive concrete with various graphite contents, specimen dimensions and applied voltages. For this purpose, six different mixtures (the control mixtures and five conductive mixtures with steel fibers of 2% by weight of coarse aggregate and graphite as fine aggregate replacement at the levels of 0%, 5%, 10%, 15% and 20% by weight) were prepared and concrete blocks with two types of dimensions were fabricated. Four test voltage levels, 48 V, 60 V, 110 V, and 220 V, were applied for the electrical and thermal tests. Test results show that the compressive strength of specimens decreases as the amount of graphite increases in concrete. The rising applied voltage decreases electrical resistivity and increases heat of concrete. Meanwhile, higher electrical current and temperature have been obtained in small size specimens than the comparable large size specimens. From the results, it can be concluded that the graphite contents, applied voltage levels, and the specimen dimensions play important roles in electrical and thermal properties of concrete. In addition, the superior electrical and thermal properties have been obtained in the mixture adding 2% steel fibers and 10% graphite.

• 한국추진공학회지
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• 제8권2호
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• pp.73-84
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• 2004

로켓모터의 성능을 확인하기 위해 지상에서 연소시험을 수행하여 추력, 압력, 온도. 그리고 변형률 등 필요한 데이터를 계측하지만 측정된 추력은 시험대 동특성으로 인해 실제 추력과는 달리 과도진동이 포함된 왜곡된 형태를 나타낼 수 있다. 이러한 경우에는 추력 최대치나 추력 상승시간 등 로켓모터의 성능을 결정하는 값들의 정확한 값을 얻지 못할 수 있다. 따라서 본 논문에서는 이러한 추력 왜곡 현상의 원인을 분석하고 그 문제점을 해결하기 위한 이론적인 방법을 제안한다. 또한 제안된 방법을 가상 시험대에 적용하여 제안한 방법의 적용 가능성을 확인하고, 차후 실험 데이터를 이용한 추력 추정의 기본적인 방향을 제시하고자 한다.

• 한국식품조리과학회지
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• 제8권3호
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• pp.297-307
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• 1992

This study has investigated a scientific approach to the manufacture of Yackwa, made by different frying conditions and has assessed texture characteristics through sensory evaluation and instrumental test. A standard Yackwa was made by frying at 150$^{\circ}C$ for 8 minutes and then soaking for 10 minutes in the newly developed syrup whose viscosity and sweetness were similar to expensive honey. The mixing ratio of the developed syrup was corn syrup: sugar: dextrose=32 : 1.5 : 1 (by weight), and me syrup was double-boned in a water bath for 20 minutes and men cooled to 25 C. As me results of sensory evaluation and instrumental test for Yackwa made by various frying conditions, the lower the frying temperature or me longer the frying time was the higher values of hardness and fracturability, while adhesiveness was the lower in almost all conditions. In the sensory evaluation of Yackwa with the similar outer color, mere were significant differences in me inner color, Crispiness and levels of rising and cracking.

• 한국해안·해양공학회논문집
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• 제22권4호
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• pp.272-278
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• 2010

탄산화에 미치는 온도의 영향에 대해서는 매우 상반된 2가지의 주장이 존재하는데, 온도증가는 탄산화 반응을 가속화시켜 탄산화 깊이를 증가시킨다는 주장과 탄산화 반응을 일으키는 최적의 온도조건이 있으며, 탄산화 깊이는 이러한 최적의 온도조건에서 가장 큰 값을 가진다는 주장이다. 일반적으로 탄산화는 시멘트 수화물 중 수산화칼슘과 이산화탄소의 화학반응으로 생성되는 것으로 알려져 왔고 많은 탄산화 연구들도 이에 집중되어 왔다. 그러나, 최근의 몇몇 연구에서는 수산화칼슘을 제외한 다른 시멘트 수화물도 탄산화 반응이 일어난다는 결과를 발표하고 있다. 본 연구에서는 온도의 탄산화에 미치는 영향을 파악하기 위하여 탄산화 온도에 따른 탄산화 깊이와 탄산화 반응물과 생성물에 대한 실험을 수행한다. 또한, 실험결과의 분석을 통하여 수산화칼슘이외의 수화생성물이 탄산화에 미치는 영향을 파악하고자 하였다. 탄산화 깊이는 페놀프탈레인 용액법으로 측정하였고, 탄산화 전후의 반응물과 생성물은 열중량분석기(Thermogravimetric analyzer)를 이용하여 측정하였다. 탄산화 온도가 $20^{\circ}C$에서 $30^{\circ}C$로 증가하면 탄산화 깊이가 크게 증가하였지만 온도가 $30^{\circ}C$에서 $40^{\circ}C$로 증가하면 탄산화 깊이가 거의 증가하지 않았다. 이것은 탄산화 반응에 대한 최적의 온도조건이 존재할 수 있다는 증거일 수 있다. 페놀프탈레인 용액법에 의한 탄산화 깊이는 수산화칼슘과 탄산칼슘의 양이 변화하여 교차하는 영역에 존재한다. 탄산화 온도 $30^{\circ}C$와 $40^{\circ}C$에서의 수산화칼슘 이외의 시멘트 수화물에 의해 생성된 탄산칼슘양은 온도가 증가하면 감소함을 관찰할 수 있었다.

• 한국동물위생학회지
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• 제15권1호
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• pp.32-45
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• 1992

In order to establish and enzyme-linked immunosorbent assay to ILTV, field virus strain of ILTV was propagated in chorioallantoic membrane of the embryonated eggs. purified and used as antigen. The antisera selected from the field samples and immunized chickens based on serum neutralization test were used as the standard positive and negative sera in all tests. It was found that optimal antigen concentration was $2{\mu}g$ of protein per well and a 1 : 100 dilution of standard serum showed low background optical density with negative serum and high P/N values of positive sera. A 1 : 500 dilution of the rabbit anti-chicken IgG peroxidase conjugate produced a high P/N values and thirty minutes was chosen as suitable time to read the optical density of the enzyme substrate reaction and optical density was consistent during the 16 hours after stopper was treated. When coated antigen was kept on microplate for varying time up to 16 hours at $4^{\circ}C$ or $37^{\circ}C,$ no significant difference was observed between the treatment. The coated antigen could be kept without change of antigenicity for at least one month at $-70^{\circ}C,\; -20^{\circ}C,\; 4^{\circ}C$ and room temperature. When blocking buffer contanining bovine serum albumin was mixed directly with conjugate and serum at 10% level induced higher P/N values compared to blocking antigen coated microplate with the same blocking buffer. The coefficience of correlation between ELISA and SN test was 0.577. When antibody response of chickens, vaccinated with ILTV, was examined by ELISA and SN test, antibody rising and decay pattern between the two test was similar until 11 weeks of age. However 12 weeks onward antibody titer checked on by SN test was slightly lower than that tested by ELISA.

• 한국화재소방학회논문지
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• 제28권2호
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• pp.76-81
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• 2014

화재와 같은 고온 시 구조부재의 붕괴를 방지함으로써 재실자와 소방관계자 그리고 재산을 보호할 수 있는 방법은 구조부재의 내화성능을 확보하는 것이며, 이는 시방적 내화설계방법인 내화시험을 통하여 확보되어 왔다. 그러나 내화시험에 수반되는 시험체 제작과 운반 그리고 막대한 시험 비용의 반복적 사용 등은 새로운 공법과 재료 개발의 문제점으로 대두되었다. 따라서 본 연구에서는 일반 등급(SS 400) 강재의 고온 시 항복강도, 탄성계수와 열전달 및 열응력 해석을 적용하여 H형강 보부재의 표면온도 상승 및 고온 시 내력 변화를 평가하였다. 또한 H형강 보부재의 길이 변화에 따른 고온 시의 보부재의 내력평가를 수행하여 각각의 길이변화에 따른 내력 변화의 차이를 평가하였다.