• KSCE Journal of Civil and Environmental Engineering Research
• /
• v.34 no.1
• /
• pp.1-8
• /
• 2014

This paper deals with monitoring and analysis of temperature measurement data in concrete pylon of long span cable bridges. During the construction of Geoga Bridge in Busan-Geoje Fixed Link Project, temperature sensors were installed in several sections of hollow box type concrete pylon and temperatures along the depth of the four sides of the section have been recorded along with ambient temperature. Effects of temperature distribution on the pylon are analysed using actual measured data and results are compared with the design guideline. It was found that the temperature load model for concrete girder can be applied to box type concrete pylon. Structural analysis of the pylon due to variation of temperature distribution during the construction is performed using 3D modelling and FE program and the maximum displacements of east-west and north-south side were calculated as 0.056m and 0.121m, respectively.

• Journal of Korean Society of Steel Construction
• /
• v.9 no.3 s.32
• /
• pp.431-440
• /
• 1997

The paper describes a theoretical model for the prediction of bridge temperatures from meteorological data measured at bridge site and local meteorological center together with existing finite element heat transfer theory and solar radiation transfer theory to determine the time dependent temperature distribution of bridge. In this analytical model, the most adequate equation for the calculation of solar radiation on the bridge surface, which is dominant in day time is described based on the results of several experimental studies for the solar energy. The validity of this model is tested against field data obtained from long term experimental program on Sadang Viaduct in Seoul. Also, this paper describes the linear correlation between design variables and meteorological data to establish analytical criteria for the prediction of the average temperature, which are responsible for the longitudinal deformation of the bridges and of the vertical differential temperature profiles. which are responsible for the bending deformations from the long term experimental results.

• Electrical & Electronic Materials
• /
• v.3 no.2
• /
• pp.138-146
• /
• 1990

볼츠만 수송방정식에 관한 홀스타인의 식을 사용하여 온도는 273.deg.K, 상대전계의 세기가 1.leq.E/P..leq.30(V/cm Torr)인 때의 Na와 He 단일기체중을 통과하는 전자의 에너지분포함수와 수송계수를 계산하였다. 그리고 전자 이동속도의 결과치를 실험값과 비교하였으며 실험치와 계산치가 일치하도록 충돌단면적을 수정하여 계산에 적용하였다. 이러한 방법으로 Hesms 0.1[eV]-50[eV]까지 Na는 0.1[eV]-5[eV]까지의 에너지범위에서 결정된 운동량변환단면적의 값은 제한된 범위에서 Crompton 및 Nakamura의 값과 거의 일치하였다. 또한 이와 같이하여 계산된 Na와 He 단일기체의 충돌단면적을 이용하여 온도는 273.degK, 상대전계의 세기는 1.leq.E/P$_{o}$ .leq.30(V/cm Torr)의 범위에서 Na-He 혼합증기의 혼합비율을 He:Na는 99.5:0.5, 99:1, 9:1. 1:1로 변화시켜 특성에너지, 평균에너지, 전자이동속도, 전자에너지 분포함수를 게산하였다.

• Journal of Energy Engineering
• /
• v.15 no.3 s.47
• /
• pp.188-193
• /
• 2006

This paper intends to present theoretical study and its application result of the way of the temperature distribution embodiment through the production of subdivided nod's temperature from the average, maximum and minimum temperature following acoustic speed measurement with a set of acoustic speed meters at the arbitrary section in the furnace. By measuring the acoustic speed between the speed meters, flue gas temperature field can be determined. Then Subdivided arbitrary grid's temperatures can be infered out of surrounding nod's temperature distribution, and finally the entire grid's temperature distribution will be found. In this article, theoretical background, related system setup. and real application result are examined and discussed.

• Korean Journal of Agricultural and Forest Meteorology
• /
• v.3 no.2
• /
• pp.105-113
• /
• 2001

This study was conducted to reveal the effects of local climatic conditions on the vegetative growth in a mature stand of Korean white pine based on climatic estimates. For this, the annual increments of stand variables such as DBH, height, basal area and volume were measured and estimated for seven years from 1974 to 1980. The local climatic conditions in the study site were also estimated by both a topoclimatological method and a spatial statistical technique. The local climatic conditions were then correlated with and regressed on the growth factors to reveal the relationships between the climatic estimates and the growth. It is found that relatively high temperatures had positive effects on the diameter growth. The yearly diameter growth increased when each of mean, maximum, and minimum temperature during the growing season was high. Height growth showed positively significant correlation with three climatic variables. The most important variable influencing height growth was the average of maximum temperature for 10 months from January to October. It means that the higher the average of maximum temperature for 10 months from January to October is, the more height growth of Korean white pine increases. Other climatic variables related to height growth were average of minimum temperature for 3 months in the early growing season and mean relative humidity for the growing season. Six climatic variables related to temperature had effects on basal area increment and all of them were positively correlated with basal area increment. Especially, temperatures from January to March were important factors affecting the basal area increment. In volume increment, high correlation was also recognized with most of temperature variables. This tendency was the same as the results in diameter and hight increments. This means that the volume growth increases when temperatures during the growing season are relatively high.

• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.20 no.3
• /
• pp.602-608
• /
• 2019

The purpose of this study was to calculate the temperature difference of the sectional elevation according to the asphalt thickness of the steel box girder bridge deck and provide data on the design basis accordingly. Asphalt thicknesses produced four steel box girder model specimens of 0mm, 50mm, 100m and 150mm. In each model, 17 to 23 temperature sensors were attached to upper concrete and steel box girders. Six temperature gauges were selected to compare the temperature difference with Euro codes. The maximum and lowest temperature were calculated at the reference atmospheric temperature of each model, and the temperature difference (slope) was calculated based on this calculation. Four models of temperature difference are presented at each model. The 0mm to 100mm temperature difference models showed a -0.9 to -1.5 degree lower temperature difference compared to the temperature difference of Euro codes at the top of the slab. Overall, the measured temperature difference was found to be between 5.45% and 8.33% compared to the Euro code. The standard error coefficient, which was calculated by multiplying the average temperature with the standard error, was calculated from a range of 2.50 to 2.51 times the average at the top and bottom. It is estimated that the proposed temperature difference model can be used as a basic data when calculating temperature difference criteria for bridges in Korea.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
• /
• v.10 no.1
• /
• pp.108-117
• /
• 1998

This study was performed to analyze the fluid flow characteristics and the temperature distribution of the aquarium for fish breeding. In this study, the finite volume method and turbulence k-$\varepsilon$ model with the SIMPLE computational algorithm are used to study the water flow in the aquarium. The calculation parameters are the circulating flow rate and the basin depth, and the experiments were carried out for the water flow visualization This numerical analysis gives reasonable velocity distributions in good agreement with the experimental data. As the results of the three dimmentional simulations, the sectional mean velocity increased as the sectional mean temperature increases for constant basin depth, and the mean velocity increased more rapidly for small basin depth than that of large basin depth, The mean velocity and temperature can be expressed as the function of the circulating flow rates and the basin depth.

• Journal of Korean Society of Forest Science
• /
• v.99 no.3
• /
• pp.397-403
• /
• 2010

This study was conducted to investigate the changes in soil temperature, soil moisture content, light availability (photosynthetically active radiation, PAR) and diameter growth in 46-year-old Korean pine (Pinus koraiensis Siebold et Zuccarini) plantation located in Gwangneung experimental forest after 4 years from thinning. Three different thinning intensities [control, 45%(T45), and 60%(T60) basal area reduction] were applied in 2004. Mean soil temperature and soil water content were $8.9^{\circ}C$ and 14.3% for control, $10^{\circ}C$ and 16.1% for T45 and $10.2^{\circ}C$ and 16.1% for T60, respectively. Mean soil temperature and moisture content were significantly different among the treatment plots (p<0.05). Mean PAR in control, T45 and T60 was 44, 143 and178 ${\mu}mol/m^2$/sec, respectively and the differences were also statistically significant among the treatment plots (p<0.05). Mean annual diameter growth in control, T45 and T60 was 0.4, 1.5 and 1.2 mm, respectively. Diameter growth of Pinus koraiensis was steadily increased after thinning in comparison to control. Consequently, the results suggested that soil temperature, soil moisture content and light availability were likely to last beyond the 4 years after thinning in this Korean pine plantation.

• Proceedings of the Korea Technical Association of the Pulp and Paper Industry Conference
• /
• 2001.04a
• /
• pp.184-184
• /
• 2001

캘린더령은 지펼의 표면을 평활하게 하고, 두께를 감소시켜 균일하게 하는 역할을 한다. 그러나 이는 필연적으로 불투명도와 같은 광학적 성질과 인장강도 등의 강도적 성질 의 저하를 유발한다. 따라서 캘린더링 공정변수인 온도, 압력, 속도 등이 종이의 물성에 미 치는 영향을 정확하게 파악하는 것은 캘린더령에 따라 발생할 수 있는 물성 저하를 최소화 하기 위해 필수적으로 요청된다. 본 연구에서는 최근들어 저평량화에 대한 관심이 증가하면 서 그 중요성이 더해지고 있는 불투명도가 캘린더링에 따라 변화되는 양상을 분석하기 위해 서 화상분석 기법을 이용하여 종이의 두께방향 밀도 변이를 평가하고 밀도변이와 불투명도 와의 상관관계를 해석코자 하였다. 또 캘린더링에 따른 불투명도를 저하를 최소화시키기 위 한 캘린더링 조건을 모색하였다. 캘린더링에 의해 발생하는 종이의 두께 변형은 두께방향의 위치에 따라 다르게 나 타난다. 이러한 종이의 두께 방향으로 발생하는 밀도 변이와 이에 따른 불투명도 변화를 평 가하기 위하여 동일한 평량의 종이를 캘린더령 조건을 달리하여 두께방향 밀도변이가 다른 시편을 준비하고 두께 방향 단면을 SEM으로 촬영하였다. 이후 화상분석기를 통해 단면을 이치화하고, 각 픽셀의 흑백 값을 구해 CD방향으로 평균을 내어 두께 방향에 대한 밀도 변 이를 평가하였다. 그 결과 압력보다는 온도를 높여 캘린더링한 경우 종이의 두께 방향 밀도 경사가 커진다는 사실을 확인할 수 있었다. 이는 고온에 의해 표층이 고밀화되고 상대적으 로 내부가 별크해졌기 때문이다. 이러한 밀도 변이가 종이의 광학적 성질인 불투명도에 미 치는 영향을 구명하기 위해서 캘린더링 전후에 두께 및 불투명도를 측정하여 5% 유의수준 에서 회귀분석을 실시하였다. 밀도경사를 지닌 종이의 불투명도를 이론적으로 해석하기 위해 다층 모델을 가정하 고 각 층의 비광산란계수(5)와 비광흡수계수(k)를 달리 부여하고 Kubelka-Munk 이론을 근 거로 하여 이론적 불투명도를 계산하였다. 불투명도에 대한 분석를 통해 동일한 두께 변형 을 가지는 샘플에 대해서 압력보다는 온도를 증가시켜 두께를 감소시키는 캘린더링 처리가 불투명도의 저하를 최소화한다는 것을 확인하였다.

• Proceedings of the Korean Vacuum Society Conference
• /
• 2011.02a
• /
• pp.73-73
• /
• 2011

Zn-Sn-O (ZTO) 다성분계 산화물 박막은 일반적인 rf 스퍼터법으로 성막할 경우 비정질상으로 성장하여 결정질 산화물 박막에 비해 우수한 표면평탄도와 식각 단면을 제공한다. 비정질임에도 불구하고 넓은 자유전하 농도 범위에서 높은 Hall 이동도를 제공할 수 있는 것으로 보고되어 있어 비정질 산화물의 투명도전성 박막에 대한 관심이 높아지고 있다. 투명 TFT에 적용되는 또 다른 비정질계 산화물 박막인 In-Zn-O (IZO) 박막에 비해 ZTO 박막은 상대적으로 제한된 연구가 이루어졌으나, In의 함유되지 않아 경제적으로 유리하고, 특히 SnO2의 우수한 기계적 및 화학적 특성과 ZnO의 내환원성 특성을 잠재하고 있는 유망한 투명도전성 박막재료이다. 본 연구에서는 Zn-Sn-O계 박막을 통상의 rf 스퍼터법으로 성막하여 조성, 증착 온도, 그리고 열처리 온도에 따른 ZTO 박막의 구조적인 특성 변화와 이에 따른 전기적 및 광학적 특성 변화에 대하여 고찰하였다. ZnO 타겟과 SnO2 타겟을 사용하여 co-sputtering하여 ZnO의 부피 분률을 13~59 mol%까지 변화되도록 조절하여 증착하였다. 증착 온도는 상온, 150 및 $300^{\circ}C$로, 그리고 성막가스 중의 산소분률은 0%, 0.5% 및 1% 로 변화시켰다. 40 mol% 이상의 ZnO를 함유한 ZTO 박막은 가시광 영역에서의 평균 광투과도는 좋으나 전기적인 특성이 열악하였으며, ZnO 분율이 낮은 ZTO 박막은 10-2~10-3 ohm-cm 정도의 비교적 낮은 비저항을 나타내었으나 광투과도 면에서 떨어지는 단점을 보였다. 평균 광투과도는 증착 온도가 증가할수록, 그리고 산소의 양이 증가할수록 향상 되었다. 자유전하농도가 1017~1020 cm-3 정도의 넓은 범위에서 10 cm2/Vs 을 넘는 홀 이동도를 가지는 ZTO 박막의 증착이 가능함을 확인하였으며, 이로부터 투명 TFT 소자로 적용이 가능성이 있음을 보였다. EPMA를 이용한 정량분석 및 XRD를 이용한 구조분석과 연계한 ZTO 박막의 물성 및 최적 조건에 대한 논의가 이루어질 것이다.