• 한국안전학회지
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• 제9권4호
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• pp.119-124
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• 1994

The considerations in the noise control by enclosure are the rise of temperature and sound pressure, transmission loss, absorption coefficient of the materials, the structure of the soundproof panels, an opening and coincidence frequency. But it is very difficult that we obtain the accurate data about those in design, so, the noise reduction after enclosing does not correspond with the calculation. The difference of the noise reduction between the calculation and the measurement was 8.2dBA, and we can obtain the approximate result as the following formula which correct 10dBA, safely.

• 한국지반신소재학회논문집
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• 제18권1호
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• pp.79-89
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• 2019

본 연구는 기존의 콘크리트 투수블록이 아닌 재활용 합성수지를 활용하여 제작된 투수블록의 열섬현상 완화의 기능성 측면인 표면온도의 저감효과를 확인하고자 야외계측과 실내실험을 진행하였다. 야외계측은 건조한 상태와 습윤상태를 고려하여 3일 동안 계측하였고, 실내실험은 건조 조건, 강우 모사 조건, 표층 습윤 조건 등으로 구분하여 온도의 변화와 실험 후 함수율의 증발비율을 확인하였다. 야외계측 결과, 가뭄이 지속되거나 일정수준의 수분이 표층에 없는 건조한 상태에서는 수분의 증발에 의한 기화잠열로 냉각효과가 발휘되기 보다는 투수블록 표면의 알베도에 의한 차이로 표면의 온도가 감소하는 것을 확인하였다. 실내실험 결과, 재생 합성수지 투수블록(RS 투수블록)은 콘크리트 투수블록보다 건조한 상태일때는 더 높은 표면온도를 기록하였으나 강우 모사조건에서는 공극내 수분의 증발이 모세관력에 의해 지속적으로 유지되어 더 높은 온도 저감율 보이는 것으로 나타났다. 실내실험 후 증발율을 측정한 결과 수분의 증발율이 높을수록 온도의 저감효과는 증가하는 것을 확인하였다. 이 결과를 바탕으로 증발율과 온도의 저감율에 대한 상관관계식을 도출하였다.

• 대한전기학회논문지:전기물성ㆍ응용부문C
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• 제49권3호
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• pp.186-195
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• 2000

In this paper, partial discharge (PD) measurement was performed to evaluate the quality of the cable joint and termination constructions. The resistive coupling technique for PD detection using resistivity of semiconducting layer of the cable in the accessories, such as joints and terminations. With high frequency PD (HEPD) measurement, an excellent sensitivity below 20pC could be achieved under unshielded condition. The localization of the defects in the accessories could be identified. During heating cycle, PDs were monitored and analyzed. At that time, the PDs were dependent on the temperature of the heating cycle and showed cyclic behaviors, which were attributed to local delamination of the interfaces, between epoxy unit and stress relief cone(SRC) and between SRC and cable, due to the difference of thermal expansion. As a conclusion, HFPD measurement technique was proven to be an effective diagnostic method for qualification of extra high voltage (EHV) cable accessories. With this technique, the optimal design of the components of the accessories could be verified not only in an early stage but also under operating condition. This technique would result in the improvement of the reliability of the EHV cable accessories.

• 한국기계가공학회지
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• 제18권8호
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• pp.74-81
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• 2019

Cars are inspected in the transport sector for their ability to achieve the greenhouse gas reduction targets. A vehicle (automobile) inspection broadly consists of regular and total checks, and both the safety level and the amount of exhaust gas are checked simultaneously during a vehicle inspection. This study deals with the efficiency of a soot probe to measure soot emissions from diesel vehicles. When the vehicle exhaust gas measurement is performed, there may be a difference between the exhaust gas temperature and the soot suction amount because of the different shape and angle of the exhaust port for each vehicle type. This may result in some incidents where the correct inspection nonconforming vehicle is not selected. Therefore, in this study, the shape of the probe was improved to increase the soot measurement efficiency under the condition of the exhaust pipe angle change.

• 한국생산제조학회지
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• 제26권4호
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• pp.378-386
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• 2017

Friction stir welding was performed using six welding conditions to evaluate the mechanical properties and microstructure of the welded zone based on its temperature change in the extruded plate of magnesium alloy AZ61. The welded zone temperature was measured using a thermocouple, and the maximum temperature ranges for the advancing and retreating sides were approximately $210-315^{\circ}C$ and $254-339^{\circ}C$, respectively. Depending on the welding conditions, a temperature difference of more than $100^{\circ}C$ was observed. In addition, the maximum yield strength and maximum tensile strength of the welded component was 84.4% and 96.9%, respectively, of those of the base material. For the temperatures exceeding $300^{\circ}C$, oxidation defects occurred in the weld zone, which decreased the mechanical strength of the weld zone. The microstructure and texture confirmed that fracture occurred because of the grain size deviation of the welding tool and the severe anisotropy of the texture of the welded joints.

• 한국추진공학회지
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• 제22권4호
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• pp.68-75
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• 2018

본 연구는 설계된 고온 고압 연소식 공기가열기의 성능을 확인하기 위한 성능시험과 그 결과분석에 대한 것이다. 총 4가지의 시험조건에 대한 시험과 3가지 조건에 대한 레이크 측정 시험이 수행되었다. 성능시험결과 목표 온도와 공급 유량조건을 모두 만족하였으며, 최대 공급온도 2000 K, 최대 연소압력 40 bar의 조건을 만족하였다. 공급된 메탄의 유량은 이론값보다 최대 36% 증가하였으며, 측정된 온도는 이론적으로 계산된 온도보다 최대 19.6%의 차이를 보였다.

• 한국태양에너지학회 논문집
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• 제32권3호
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• pp.138-145
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• 2012

Because of the climate changes and the development of building technologies, the cooling loads have been increased. Among the various renewable energies, geothermal energy is known as very useful and stable energy for heating and cooling of building. This study proposes a road snow-melting system of which heat is supplied from GSHP(Ground source heat pump) in viewpoint of the initial investment and annual running performance, which is also operating as a main facility of heating and cooling for common spaces. The results of this study is as followings. From the site measurement, it is found out that the road surface temperature above the geothermal heating pipe rose up to $5^{\circ}C$, which is the design temperature of road snow-melting, after 2 hours' operation and average COP(Coefficient of performance) was estimated as 3.5. The reliability of CFD has confirmed, because the temperature difference between results of CFD analysis and site measurement is only ${\pm}0.4^{\circ}C$ and the trend of temperature variation is quite similar. CFD analysis on the effect of pavement materials clearly show that more than 2 hours is needed for snow-melting, if the road is paved by ascon or concrete. But the road paved by brick is not reached to $5^{\circ}C$ at all. To evaluate the feasibility of snow-melting system operated by a geothermal circulation which has not GSHP, the surface temperature of concrete-paved road rise up to $0^{\circ}C$ after 2 hour and 40 minutes, and it does never increase to $5^{\circ}C$. And the roads paved by ascon and brick is maintained as below $0^{\circ}C$ after 12 hours geothermal circulation.

• 대한원격탐사학회:학술대회논문집
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• 대한원격탐사학회 2007년도 Proceedings of ISRS 2007
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• pp.33-36
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• 2007

We have persistently constructed gridded products of surface wind/wind stress over the world ocean using satellite scatterometer (ERS and Qscat). They are available for users as the Japanese Ocean Flux data sets with Use of Remote sensing Observation (J-OFURO) data together with heat flux components. Recently, a new version data of the Qscat/SeaWinds based on improved algorithm for rain flag and high wind-speed range have been delivered, and allowed us to reconstruct gridded product with higher spatial resolution. These products are validated by comparisons with in-situ measurement data by mooring buoys such as TAO/TRITON, NDBC and the Kuroshio Extension Observation (KEO) buoys, together with numerical weather prediction model products such as the NCEP-1 and 2. Results reveal that the new product has almost the same magnitude in mean difference as the previous version of Qscat product and much smaller than the NCEP-1 and 2. On the other hand, it is slightly larger root-mean-square (RMS) difference than the previous one and NCEPs for the comparison using the KEO buoy data. This may be due to the deficit of high wind speed data in the buoy measurement. The high resolution product, together with sea surface temperature (SST) one, is used to examine a new type of relationship between the lower atmosphere and upper ocean in the Kuroshio Extension region.

• Nuclear Engineering and Technology
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• 제54권10호
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• pp.3888-3896
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• 2022

Nuclear data is the basis of reactor physics analysis. This paper aim at studying the influence of major evaluated nuclear data libraries, CENDL-3.2, ENDF/B-VIII.0, JEFF-3.3, and JENDL-4.0u, on the neutronics modelling of CEFR start-up tests. Results show these four libraries have a good performance and consistency in the modelling CEFR start-up tests. The JEFF-3.3 results exhibit only an 8 pcm k_eff difference with the measurement. The difference in criticality is decomposed by nuclide, which shows the large overestimation of CENDL-3.2 is mainly from the cross-section of ⁵²Cr. Except for few cases, the calculation results are within 1σ of measurement uncertainty in control rod worth, sodium void reactivity, temperature reactivity, and subassembly swap reactivity. In the evaluation of axial and radial reaction distribution, there are about 65% of relative errors that are less than 5% and 82% of relative errors that are less than 10%.

• 한국방사선학회논문지
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• 제6권6호
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• pp.521-529
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• 2012

본 연구의 목표는 신발 굽 높이에 따른 Kager씨 삼각 면적의 방사선영상 변화와 후종족부의 표면온도 변화를 알아보고자 연구하였다. 카이거씨 면적은 단순 방사선촬영검사와 인피니티 영상저장전송시스템을 이용하여 측정 하였다. 후종족부의 표면온도는 전산화적외선체열검사를 이용하여 측정하였다. 운동화 착용 대상자에게 신발 굽 높이가 다른 하이힐을 착용시켜 카이거씨 삼각 면적과 후종족부의 표면온도 차이를 분석 하였다. 하이힐 대상자들은 운동화 대상자들에 비하여 카이거씨 삼각 면적이 $0.88cm^2$, 후종족부의 표면온도가 $1.4^{\circ}C$ 각각 감소하였다. 최고신장과 최저신장의 카이거씨 면적과 표면온도의 차이는 운동화와 하이힐에서 각각 $0.9cm^2$, $1.2cm^2$, $1.6^{\circ}C$, $0.5^{\circ}C$이며 모두 미세한 차이를 나타냈다. 최고체중과 최저체중의 카이거씨 면적과 표면온도의 차이는 운동화와 하이힐에서 각각 $1.8cm^2$, $0.8cm^2$, $1.1^{\circ}C$, $0.2^{\circ}C$이며 체중이 높을수록 카이거씨 면적과 표면온도가 감소하였다. 하이힐 최장시간 착용자와 최저시간 착용자의 카이거씨 면적과 표면온도의 차이는 각각 $0.8cm^2$, $1.4^{\circ}C$, 이며 착용시간이 증가함에 따라 카이거씨 면적과 표면온도가 감소하였다. 결론적으로 하이힐을 장시간 착용하면 후종족부 통증과 혈류 장애를 유발 할 것으로 고려된다.