The accidents occurred by unstable material which is easily exploded or burnt up were caused by heat and collision under the condition of relatively low temperature without oxygen, have been reported frequently. However, the amount of the unstable material is getting higher by development of fine ceramic research area even though its dangerous characteristic is disregarded. This research studied a heat stability and measured boiling point of various carpet material. Carpet has been used in home as well as general indoor usage. Now a day, carpet material which is hardly burnt has been on commercial, but its detailed unstable conditions is not mentioned. This research reports the measurement of the initial temperature of generation heat and heat-radiation change on differential scanning calorimeter (DSC). The DSC data of nylon bulked continuous filament (N-BCF) yam 100%, nylon (NY), poly propylene (PP), and a new material named polytrimethylene terephthalate (PTT) are studied and researched about the effect of them using TGA, furnace, and direct-burning experiment.

고층건물에 작용하는 풍압은 시간과 공간적으로 불규칙적이며, 일반적으로 사용되는 통계적 수법(저차 모멘트 등) 및 퓨리어 해석 등으로는 이러한 복잡한 현상을 이해하기에 적합하지 않다. 본 연구에서는 고유직교함수전개법(Proper Orthogonal Decomposition)을 고층 연돌에 작용하는 변동압력에 적용하여, 변동 풍압 및 풍력의 숨어진 구조를 찾아내고 해석하였다. 이 연구로부터 풍방향과 풍직각 방향의 변동풍력은 극히 소수의 POD모드를 통하여 얻어짐을 알 수 있었다. 또한, 이 연구를 통하여 고층 연돌에 작용하는 주요한 대칭 및 비대칭 POD 모드의 물리적 의미를 파악할 수 있었다.

  Exact solutions for practical-size problems in job shop will be highly inefficient. Scheduling heuristics, therefore, are typically found in the literature. If we consider real-life situations such as machine breakdowns, the existing scheduling methods

Carbonization products C1, C2, C3, C4 and C5 were prepared by the carbonization of date pit in limited air, at 500, 600, 700, 800 and 1000℃, respectively. C1-V-600, C3-V-600, C1-V-1000 and C3-V-1000 were prepared by thermal treatment of C1 and C3 under vacuum at 600 and 1000℃. The textural properties were determined from nitrogen adsorption at 77 K and from carbon dioxide adsorption at 298 K. The surface pH, the FTIR spectra and the acid and base neutralization capacities of some carbons were investigated. The amounts of surface oxygen were determined by out-gassing the carbon-oxygen groups on the surface as CO2 and CO. The adsorption of water vapor at 308 K on C1, C2, C3 and C4 was measured and the decomposition of H2O2 at 308 K was also investigated on C1, C2, C3, C4 and C5. The surface area and the total pore volume decreased with the rise of the carbonization temperature from 500 to 1000℃. The adsorption of water vapor is independent on the textural properties, while it is related to the amount of acidic carbon-oxygen groups on the surface. The catalytic activity of H2O2 decomposition does not depend on the textural properties, but directly related to the amount of basic carbon-oxygen complexes out-gassed as CO, at high temperatures.

우라늄 변환시설의 라군 슬러지에 함유된 질산염의 안정적 처리를 위해 물 첨가 용해를 실시한 뒤, 여과 케이크의 안정화 특성에 대하여 알아보았다. 물 용해에 의해 대부분의 질산염은 고농도 질산염 용액으로 제거되었으므로, 여과 케이크의 열분해는 에서 하나의 단계로 수행하였다. Muffle furnace를 이용하여 에서 5시간동안 여과 케이크의 열분해를 실시한 결과 라군 1 슬러지에 포함된 U은 의 열분해와 함께 의 형태로 안정화 되었다. 라군 2 열분해 잔류물의 경우에는 열분해 시 생성된 CaO가 냉각과정에서 수분과 반응하여 로 전환되는 것을 TG/DTA 분석과 XRD 분석을 통해 확인할 수 있었지만, 처분장에서 대기중 노출이나 지하수의 침출 등에는 안정한 화합물로 알려져 있으므로, 특별한 첨가제의 첨가 없이 단순 열분해 후 처분이 가능할 것으로 판단된다.

Thermolysis of Cu(NO3)2·3H2O impregnated activated carbon fiber (ACF) was studied by means of XRD analysis to obtain Cu-impregnated ACF. Cu(NO3)2·3H2O was converted into Cu2O around 230℃. The Cu2O was reduced to Cu at 400℃, resulting in ACF-C(Cu). Some Cu particles have a tendency to aggregate through the heat treatment, resulting in the ununiform distribution in ACF. Catalytic decomposition of NO gas has been performed by Cu-impregnated ACF in a column reactor at 400℃. Initial NO concentration was 1300 ppm diluted in helium gas. NO gas was effectively decomposed by 5~10 wt% Cu-impregnated ACF at 400℃. The concentration of NO was maintained less than 200 ppm for 6 hours in this system. The ACF-C(Cu) deoxidized NO to N2 and was reduced to ACF-C(Cu2O) in the initial stage. The ACF-C(Cu2O) also deoxidized NO to N2 and reduced to ACF-C(CuO). This ACF-C(CuO) was converted again into ACF-C(Cu) by heating. There was no consumption of ACF in mass during thermolysis and catalytic decomposition of NO to N2 by copper. The catalytic decomposition was accelerated with increase of the reaction temperature.

An aqueous solution of a commercial liquid synthetic detergent for kitchen use was photodecomposed in the presence of titanium dioxides powder under an atmosphere of air at room temperature. Titanium dioxides were prepared by sol-gel method from titanium iso-propoxide at different R ratio(H2O/titanium iso-propoxide) and calcined at 500℃. All titanium dioxides were characterized by XRD, BET surface area analyzer and UV-VIS spectrometer. The surface area of titanium dioxides prepared at R ratio=6 appeared higher volume about 20% than commercial TiO2 catalysts. XRD patterns of titania particles were observed mixing phase together with rutile and anatase type. Titanium dioxides prepared by sol-gel method show higher activity about 6% than commercial TiO2 catalysts on the photocatalytic degradation of a commercial liquid synthetic detergent for kitchen. The concentration of the detergent decreased to about 90% of its initial value at illumination times of 2 hour. Illumination for 30 minutes decreased the concentration of oxygen to about one-fifth of the initial value.

Decomposition of ozone at room temperature was investigated by comparing between commercial monolithic ozone decomposition catalyst (ODC, MnO2) filter and monolithic photocatalyst (TiO2) filter. The effects of residence time, UV (ultraviolet, A type) irradiation, and upstream ozone concentration on the ozone conversion were discussed. UV ray was irradiated using four BLB (black light blue) lamps (λ: 310∼ 400nm) of constant intensity. The upstream concentration of ozone was controlled by an electrostatic ozone generator. For ODC performance, the presence of UV irradiation slightly affected initial ozone conversion compared with no UV irradiation condition. However, for photocatalyst, the ozone was highly decomposed in the presence of UV irradiation. Long time performances of the both catalysts were evaluated by a real-time ozone monitoring system during 120 hours. The results show that the UV irradiation enhanced the ozone conversion for the both catalysts.

속리산 국립공원 내 용바위골 지역(a.s.1. 560∼640 m)의 신갈나무림에서 토양에 축적된 유기탄소, 질소, 인 및 칼륨의 함량을 측정하고 또 O1son(1963)의 부지수곡선 모델을 적용하여 낙엽의 분해상수(k)와 분해시간(t)를 측정하였다. 유기탄소량은 L층 231.25 g m-2, F층 291.50 g m-2, H층 166.91 g m-2, 그리고 A1층 174.51 g m-2, 로 L층과 F층에서 높

이 논문은 환(環)을 형성하는 부분네트웍들로 이루어진 sparse network의 특수한 형태에서 최단거리 결정을 위한 효율적인 앨고리즘을 제안한다. 제시된 앨고리즘은 소위 비환(非換) 형태의 sparse network에 대한 최단거리 결정 앨고리즘의 확장이라 할 수 있다. 도우넛 형태를 갖는 sparse network에 대해 최단거리 결정을 위한 접근법으로 하나는 정점제거 방법이고, 다른 하나는 선분제거 방법이다. 여기서 제안된 앨고리즘은 일반적인 n

LiMn2O4 catalyst for CO2 decomposition was synthesized by oxidation method for 30 min at 600℃ in an electric furnace under air condition using manganese(II) nitrate (Mn(NO3)2·6H2O), Lithium nitrate (LiNO3) and Urea (CO(NH2)2). The synthesized catalyst was reduced by H2 at various temperatures for 3 hr. The reduction degree of the reduced catalysts were measured using the TGA. And then CO2 decomposition rate was measured using the reduced catalysts. Phase-transitions of the catalysts were observed after CO2 decomposition reaction at an optimal decomposition temperature. As the result of X-ray powder diffraction analysis, the synthesized catalyst was confirmed that the catalyst has the spinel structure, and also confirmed that when it was reduced by H2, the phase of LiMn2O4 catalyst was transformed into Li2MnO3 and Li1-2δMn2-δO4-3δ-δ' of tetragonal spinel phase. After CO2 decomposition reaction, it was confirmed that the peak of LiMn2O4 of spinel phase. The optimal reduction temperature of the catalyst with H2 was confirmed to be 450℃(maximum weight-increasing ratio 9.47%) in the case of LiMn2O4 through the TGA analysis. Decomposition rate(%) using the LiMn2O4 catalyst showed the 67%. The crystal structure of the synthesized LiMn2O4 observed with a scanning electron microscope(SEM) shows cubic form. After reduction, LiMn2O4 catalyst became condensed each other to form interface. It was confirmed that after CO2 decomposition, crystal structure of LiMn2O4 catalyst showed that its particle grew up more than that of reduction. Phase-transition by reduction and CO2 decomposition ; Li2MnO3 and Li1-2δMn2-δO4-3δ-δ' of tetragonal spinel phase at the first time of CO2 decomposition appear like the same as the above contents. Phase-transition at 2~5 time ; Li2MnO3 and Li1-2δMn2-δO4-3δ-δ' of tetragonal spinel phase by reduction and LiMn2O4 of spinel phase after CO2 decomposition appear like the same as the first time case. The result of the TGA analysis by catalyst reduction ; The first time, weight of reduced catalyst increased by 9.47%, for 2~5 times, weight of reduced catalyst increased by average 2.3% But, in any time, there is little difference in the decomposition ratio of CO2. That is to say, at the first time, it showed 67% in CO2 decomposition rate and after 5 times reaction of CO2 decomposition, it showed 67% nearly the same as the first time.

Thermal decomposition of the copolymer of butyl methacylate(BMA) with styrene(St) was investigated. The copolymer Was obtained at 80 ℃ in a continuous stirred tank reactor(CSTR) using toluene and benzoyl peroxide(BPO), as solvent and initiator, respectively. The reactor volume was 0.3 liters and residence time was 3 hours. The thermal decomposition followed the second order kinetics for BMA/St copolymer. The activation energies of thermal decompositon were in the ranges of 38 ~43 kcal/mol for BMA with St copolymer and a good additivity rule was observed with the composition of copolymer. The thermogravimetric trace curve agreed well with the theoretical calculation.

Mechanically driven decomposition of intermetallics during mechanical milling(MM 1 was investigated. This process for Fe-Ce and Fe-Sn system was studied using conventional XRD, DSC, magnetization and alternative current susceptibility measurements. Mechanical alloying and milling form products of the following composition (in sequence of increasing Gecontent): () bcc solid solution, +-phase (), -phase, +FeGe(B20), FeGE(B20), FeGe(B20)+,,+Ge, Ge. Incongruently melting intermetallics and decompose under milling. produces mixture of -phase and FeGe(B20), produces mixture of FeGe(B20) and phases. These facts are in good agreement with the model that implies local melting as a mechanism of new phase for-mation during medchanical alloying. Stability of FeGe(B20) phase, which is also incongruently melting compound, is explained as a result of highest density of this phase in Fe-Ge system. Under mechanical milling (MM) in planetary ball mill, FeSn intermetallic decomposes with formation and phases, which have the biggest density among the phases of Fe-Sn system. If decomposition degree of FeSn is relatively small(<60%), milled powder shows superparamagnetic behavior at room temperature. For this case, magnetization curves can be fitted by superposition of two Langevin functions. particle sizes for ferromagnetic phase determined from fitting parameters are in good agreement with crystalline sizes determined from XRD data and remiain approximately chageless during MM. The decomposition of FeSn is attributed to the effects of local temperature and local pressure produced by ball collisions.