본 연구는 온실의 관류전열량을 분석하고 예측하는데 필요한 기초자료 제공을 위하여, 공기막 이중 PO필름의 열저항식을 모델링하였고, 전도, 복사, 대류에 의한 열저항 특성을 규명하였다. 또한 열저항식의 타당성 검증을 위해 열저항식에 의한 관류전열량의 계산값과 실험값을 비교·분석하였다. 공기막 이중 PO필름의 열저항식은 PO필름, 공기막, PO필름의 직렬 열저항식으로 구성되며, 공기막은 복사와 대류에 의한 병렬 열저항식으로 구성된다. 고온부 T1의 평균온도는 276.1K, 저온부 T2의 평균온도는 266.8K로 나타났으며, 다른 조건들이 동일할 경우 챔버 내부온도가 높을수록 T1과 T2의 평균온도와 온도차가 증가하는 것을 확인할 수 있었다. 전도열저항은 0.00091K ·W−1로 전체 열저항의 1% 미만으로 매우 미미한 수준이고, 공기막의 열저항이 0.18K ·W−1로 전체 열저항의 99% 이상을 차지하는 것으로 나타났다. 공기막의 경우 대류열 저항이 복사열저항에 비해 1.33~2.08배 정도 크게 나타났으며, 복사열저항은 평균온도의 3제곱에 반비례하고 대류열저항은 온도차가 4.7, 5.3, 5.5, 5.7, 12.3, 13.2, 13.3, 13.5, 13.8 및 14.0K로 증가할 때 각각 0.78, 0.75, 0.74, 0.73, 0.57, 0.56, 0.56, 0.56, 0.55 및 0.55K ·W−1 로 감소하였다. 관류전열량의 계산값과 실험값의 차이는 실험조건별로 0.6~17.2W의 범위로 평균 6.9W였으며, 실험값은 계산값의 79.8~97.7% 범위로 평균 87.3% 수준으로 나타났다. 전체적인 계산값과 실험값의 관류전열량 경향성은 잘 일치하고 있으며, 공기막 이중필름의 열 저항은 공기막 두께 및 주입공기의 종류와는 직접적인 상관관계를 보이지 않았다.

A supercritical carbon dioxide (SCC) process of dispersion of multi-walled carbon nano-tubes (MWCNTs) into epoxy resin has been developed to achieve MWCNT/epoxy com-posites (CECs) with improved mechanical, thermal, and electrical properties. The synthesis of CECs has been executed at a MWCNT (phr) concentration ranging from 0.1 to 0.3 into epoxy resin (0.1 mol) at 1800 psi, 90°C, and 1500 rpm over 1 h followed by curing of the MWCNT/epoxy formulations with triethylene tetramine (15 phr). The effect of SCC treat-ment on the qualitative dispersion of MWCNTs at various concentrations into the epoxy has been investigated through spectra analyses and microscopy. The developed SCC assisted process provides a good dispersion of MWCNTs into the epoxy up to a MWCNT concentra-tion of 0.2. The effects of SCC assisted dispersion at various concentrations of MWCNTs on modificationof mechanical, thermal, dynamic mechanical thermal, and tribological proper-ties and the electrical conductivity of CECs have been investigated.

A 2D axisymmetric numerical analysis was performed to study the characteristics of charge process inside solar thermal storage tank. The interfacial area density and inertial resistance of filler material are selected as simulation parameters. The interfacial area density is varied as 800, 2000, and 4000 1/m. The inertial resistance is varied as 1, 3, and 5 1/m. When the interfacial area density increases from 800 to 4000 1/m, the discrepancy of the temperature distributions between the filler and heat transfer fluid decreases. As inertial resistance increases from 1 to 5, both of the temperature and fluid flow pattern changes considerably.

NOx from the thermal power plants are NO and NO₂. This work investigated the chemical/physical characteristics and SCR efficiency of newly prepared catalysts including tungsten (WO₃), molybdenum (MoO₃) and antimony (SbO₃) based on vanadia(V₂O5) over titania(TiO2). As a result of the examination, the surface area of the catalysts promoted with additional metals was larger and the de-NOx efficiency also was enhanced with temperature. The most efficient catalytst was V₂O5/TiO₂-WO₃(10%) at 200 °C. Such a high efficiency could contribute to reduce the ammonia slip.

This paper presents that hybrid cooler of vapor compression type and natural refrigerant circulation type is energy saving cooler using R-410a for indoor mobile telecommunication station. Its performance and operation characterists are done experimently about receiver tank, piping and heat exchanger designs for natural circulation of refrigeration and use of R-410a for fixed height location difference of indoor and outdoor cooler.

In order to determine the wear properties of CVD ceramic coatings, wear process was evaluated using the coated pin of Falex Tribosystem. Also, in order to determine the effects of coating material on wear process, TiC,N of thickness 5m∼6m coated by Thermal CVD method were applied. The wear property of TiC,N film, the higher the deposition temperature was, the closer the lattice parameter was to the amount of the standard power, and the grain size increased. According to the wear formation, under the control that there is on specific wear rate wear parameter and coating delamination, decrease with increasing sliding friction and when the coating delamination happened.

This study is about comparison of thermal and flow characteristics on the wind & radiant heat shield with STS mesh type screen for offshore plant. Numerical analysis was conducted to find transmission coefficient in the mesh and then analyse the flow characteristics about wind & radiant heat shield. The experiment method of solar radiation has been used as thermal radiation source to get the performance of radiant heat shield measurement. The sensor radiation device has been used to measure the reduction of solar radiation with various size of cells and at a distance of 0.5m and 1m from the cold face of the wind & radiant heat shield. The present study show reduction in radiation heat flux as various distance from the cold face of the radiant heat shield. Experimental results are presented for different type of mesh and distance of measurement.

본 논문에서는 주파수 선택적 투과막(FSS)이 결합된 복합재료 구조에서 구성 재료 간의 열팽창계수 차이로 잔류응력이 발생하므로 이로 인한 층간분리나 FSS의 손상 등 구조적인 파손 가능성과 잔류응력으로 인하여 변형된 FSS가 전파투과특성에 미치는 영향에 대하여 연구하였다. FSS는 단위요소의 종류, 설계변수, 배열에 따라 전파특성이 다르게 나타나므로, PSO 알고리즘을 이용하여 다이폴이 목표주파수에서 투과특성을 갖도록 설계하고 그 설계치수를 다른 N-pole 종류 단위요소(Tripole, Cross dipole, Jerusalem cross)에 적용하여, 복합재료 구조에 발생하는 잔류응력과 그로인한 구조적 손상과 전파특성을 영향성을 관찰하고 FSS패턴과 복합재료의 적층 변화에 따라 비교하였다.

폐 PVC전선의 열적분해 특성에 관한 연구를 TGA 및 고정층 반응기를 이용하여 연구하였다. 본 연구에서는 분해온도, 공기유량 및 CaO/ PVC의 비를 실험조건으로 고려하였으며, PVC전선의 열적분해과정에서 발생되는 염화수소 및 독성가스의 제거를 위한 CaO의 첨가에 대한 효과를 검증하기 위하여 PVC 전선의 열적분해 과정에서 생성되는 기상 생성물을 GC/MS를 이용하여 분석하였다. 또한 CaO의 첨가효과를 고찰하고자 액성 생성물에 대한 GC/MS을 함께 수행하였으며, 분해온도, 공기유량 및 CaO/PVC의 비에 따른 액상, 기상 및 고상 잔류물의 수율 변화를 함께 고찰하였다. 본 연구로부터 CaO의 첨가량이 증가할수록 PVC의 열적분해 과정에서 발생되는 염화수소의 제거량이 증가함을 확인하였다.

This study experimentally investigated dicyclohexylammonium 2-cyanoacrylate (CA) as a potential comonomer for polyacrylonitrile (PAN) based carbon fiber precursors. The P(AN-CA) copolymers with different CA contents (0.19-0.78 mol% in the feed) were polymerized using solution polymerization with 2,2-azobis(isobutyronitrile) as an initiator. The chemical structure and composition of P(AN-CA) copolymers were determined by proton nuclear magnetic resonance and elemental analysis, and the copolymer composition was similar to the feeding ratio of the monomers. The effects of CA comonomer on the thermal properties of its copolymers were characterized differential scanning calorimetry (DSC) in nitrogen and air atmospheres. The DSC curves of P(AN-CA) under nitrogen atmosphere indicated that the initiation temperature for cyclization of nitrile groups was reduced to around 235℃. The heat release and the activation energy for cyclization reactions were decreased in comparison with those of PAN homopolymers. On the other hand, under air atmosphere, the P(AN-CA) with 0.78 mol% CA content showed that the initiation temperature of cyclization was significantly lowered to 160.1℃. The activation energy value showed 116 kJ/mol, that was smaller than that of the copolymers with 0.82 mol% of itaconic acids. The thermal stability of P(AN-CA), evidenced by thermogravimetric analyses in air atmosphere, was found higher than PAN homopolymer and similar to P(AN-IA) copolymers. Therefore, this study successfully demonstrated the great potential of P(AN-CA) copolymers as carbon fiber precursors, taking advantages of the temperature-lowering effects of CA comonomers and higher thermal stability of the CA copolymers for the stabilizing processes.

Emulsion polymerization was carried out using RMA like MMA, EMA, BMA and Styrene(St.) as monomer for core-shell latex preparation. It was synthesized at 80℃ in the presence of anionic surfactant SLS. FT-IR, TGA and DSC analysis are used to confirm synthesized core-shell emulsion latexes and to investigate the thermal characteristics of them. From analysis of TGA and DSC, the differences of the decomposition rate and the activation energy are not so large. It considers that the pendent group is not affect of the thermal characteristics and stability on core-shell latexes, which is synthesized with RMA and Styrene.

As the Inter-floor Thermal Insulation Regulation of apartment house applies, in this study, indoor thermal performance and downward heat loss between the cases when insulation exists and doesn t exist change in the thickness of the structure slab under the inter-floor noise isolation standard, and thermal characteristic of typical floor structure will be compared and analyzed through simulation. And the resultant information will be provided as the basic data for designing Ondol heating design suitable for the property of apartment houses in Korea. As the Inter-floor Thermal Insulation Regulation applies since 2001, upward thermal performance was found to increase by 2~3% but downward heat loss decrease by approx. 30% or more representing that remarkable portion of downward heat loss is reduced. As result of comparing five prototype floor structures, upward thermal performance of the standard floor structure was found to be 70~71 W/㎡ while downward heat loss was, in the case of prototype floor structure, 10~11 W/㎡. As result of simulating the change in thermal performance as per the height of hot water supply pipes, it was found that upward thermal performance increases as the height of pipe gets higher. On the other hand, the difference of temperature between the place right above the pipe and the in-between place gets larger, which implies that thermal performance and difference of hot water temperature should be taken into account in the design of Ondol structure. The difference of upward thermal performances according to the height of pipe and downward heat losses were found to be approx. 10.8% and 5.81% respectively. The thermal performance information in prototype floor structure suggested in this study will be used for the basic data for the design of Ondol heating design.

Recent apartment houses tend to expose the problems of unbalanced floor temperatures and real temperature due to changes in thermal performance arising from reinforced insulation and air tightness. In this study, the indoor thermal environment was analyzed against the apartment unit household in the type of individual heating, central heating, and District Heating methods in order to determine the operational status of indoor thermal environments and heating system by Heating supply systems. The temperature of hot water supplied at the time the indoor loads occurs to the maximum by Heating supply systems was found to rise in order to individual heating (70℃) , central heating(47℃) and District Heating (41℃). The hot water supply frequency showed variable changes in the range of 3 to 6 times per day in cases of individual heating while periodical changes was ranging from 3 or 4 times a day in the case of central heating and district heating. The width of variation of floor surface temperatures depending on the temperature of the supply water was found to be in order of Individual Heating, District Heating, and Central Heating. The average floor surface temperature appeared similar to the hot water supply temperature pattern in the order of 26.4 to 30.2℃ for Individual Heating, 28.2 to 28.6℃ for Central Heating, and 24.8 to 29.4℃for District Heating. In the case of non-heating where heating is not implemented, the temperature of the floor surface was 22.8℃ to 26.0℃ showing the same temperature as the indoor temperature. Heating supply appeared to be maintained in a stable manner overall in a sporadic manner ranging from 3 to 6 times a day, which was maintained in a stable manner on the whole regardless of the heating method.

This study intended to collect data for evaluating the meteorological value of Upo Wetland which is the largest wetland in the downstream of Nakdong River. The observations were conducted in summer at the Upo Wetland and its surrounding paddy field that is the converted areas from a wetland to a paddy field. The following results are obtained: 1) The temperature of Upo Wetland area was 1˚C lower than the surrounding area during the day while it was a little higher during the night.; 2) The maximum wind speed in the Upo Wetland area was 3.5 m/s which is stronger than 1.6 m/s of its surrounding area. The south wind was observed in the farmland for most of the day while north winds and south winds alternated between day and night in Upo Wetland.; 3) In heat budget analysis, Upo Wetland was wasted in the form of latent heat rather than sensible heat in daytime.

The combustion reaction of polyvinylchloride(PVC) was investigated using a thermogravimetric technique under an air atmosphere condition at several heating rates from 10 to 50℃/min. To obtain information on the kinetic parameters, the dynamic thermogravimetric analysis curve and its derivative were analyzed by a variety of analytical methods such as Kissinger, Friedman, Chatterjee-Conrad, Ozawa and Coats-Redfern methods. The combustion reaction of PVC proceeded in two steps; the first step was caused by the dehydrochlorination process in PVC, and the second step by the combustion of polyene. The comparative works for the kinetic results obtained from various methods should be performed to determine the kinetic parameters, because there are tremendous differences in the calculated kinetic parameters depending upon the mathematical method taken in the analysis.

The effects of thermal treatment conditions on ADU (ammonium diuranate) prepared by SOL-GEL method, so-called GSP (Gel supported precipitation) process, were investigated for kernel preparation. In this study, ADU compound particles were calcined to particles in air and Ar atmospheres, and these particles were reduced and sintered in 4%-/Ar. During the thermal calcining treatment in air, ADU compound was slightly decomposed, and then converted to phases at . At , the phase appeared together with . After sintering of theses particles, the uranium oxide phases were reduced to a stoichiometric . As a result of the calcining treatment in Ar, more reduced-form of uranium oxide was observed than that treated in air atmosphere by XRD analysis. The final phases of these particles were estimated as a mixture of and .

The combustion reaction of polypropylene was investigated using a thermogravimetric technique under an air atmosphere condition at several heating rates from 10 to 50℃/min. To obtain information on the kinetic parameters, the dynamic thermogravimetric analysis curve and its derivative were analyzed by a variety of analytical methods such as Kissinger, Friedman, Freeman-Carroll, Chatterjee-Conrad, Ozawa and Coats-Redfern methods. The comparative works for the kinetic results obtained from various methods should be performed to determine the kinetic parameters, because there are tremendous differences in the calculated kinetic parameters depending upon the mathematical method taken in the analysis.

Both photoluminescence and thermal characteristics for SrAl2O4:Eu+2,Dy+3 phosphors synthesizedwith various aluminum compounds (α-Al2O3, γ-Al2O3, amorphous-Al2O3 and Al(OH)3) were investigated in thisstudy. The formation temperature of the host SrAl2O4 crystal is changed by these various aluminumcompounds, as a result of the different thermal decomposition temperature of SrCO3 phase. Among thesecompounds, the amorphous-Al2O3 phase shows the lowest formation temperature of the host SrAl2O4 crystal.The PL emission and excitation spectra of SrAl2O4:Eu+2, Dy+3 phosphor are not affected by these aluminumcompounds. After the removal of the Xenon lamp excitation (360nm), however, the excellent long-phosphorescent property of the phosphor is obtained by the amorphous-Al2O3 phase, although the decay timefor all phosphors decrease exponentially.

This paper was studied on the characteristics of acid resistance and thermal shock for epoxy coatings in the strong acidic environment. The exhaust gas system, such as a air preheater, desulfurization equipment, for industrial boiler is damaged by dew point corrosion. To protect the acid corrosion, the coating using nonmetal was applied. The electrochemical polarization test, acid resistance and thermal shock test for epoxy coatings were carried out. And the acid resistance and thermal shock characteristics, aspect, and electrochemical anti-corrosion characteristics for epoxy coatings in the strong acidic environment were considered. The main results are as followings: As the epoxy glass flake coating by acidic thermal shock was damaged to the crack, blistering and elution etc., the current density of epoxy glass flake coating is high. But the damage of epoxy metal complex coating by acidic thermal shock was not occurred. Therefore the characteristics of acid resistance and thermal shock for epoxy metal complex coating is better than those for epoxy glass flake coating.