• 한국농림기상학회지
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• 제7권1호
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• pp.57-65
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• 2005

토양은 리터의 축적, 분해, 뿌리호흡을 포함하는 토양호흡을 통해 많은 양의 탄소를 저장 또는 방출할 수 있다. 이러한 토양의 주요한 탄소 및 양분의 공급원은 낙엽낙지의 유입과 유입된 낙엽낙지의 분해이며 생태계로 돌아가는 영양의 약 60%가 낙엽에서 유래되는 것으로 알려져 있다. 본 연구의 목적은 천연자연림으로 잘 보존된 경기도 광릉시험림의 온대낙엽활엽수림의 리터 생산량과 분해속도가 토양호흡의 계절적 변 이에 미치는 영향을 파악하고 낙엽층과 토양호흡간의 관련성을 찾아 생태계에서의 탄소순환을 이해하기 위한 것이다. 광릉 낙엽활엽수림에서 2003년 생산된 리터의 총량은 1489 Cm/sup -2/ yr/sup -1/ 이었으며 조사지의 우점종인 졸참나무, 서어나무, 까치박달의 순수 낙엽의 총량은 1189 Cm/sup -2/ yr/sup -1/이었다. 낙엽의 분해율은 조사기간인 1년 동안 졸참나무는 24.2%(k = 0.28), 서어나 무는 25.7％(k = 0.30), 까치박달은 33.0%(k = 0.46)이었 다. AOCC를 이용한 연속적인 토양호흡 측정결과 연간 토양호흡량은 629.69 Cm/sup -2/ yr/sup -1/이었으며 이 중 리터 분해가 차지하는 비율은 약 5％인 309 Cm/sup -2/ yr/sup -1/이었다. 토양호흡의 동절기 최저값은 7.4±1.4g Cm/sup -2/ month/sup -1/ 이었으며 이 시기의 리터 분해속도도 0.8g Cm/sup -2/ month/sup -1/로 최저값을 나타내었다. 하절기에는 토양 호흡과 리터 분해속도 모두 증가하여 111.5 ± 16.2g Cm/sup -2/ month/sup -1/와 11.4g Cm/sup -2/ month/sup -1/로 최고값을 보였다. 토양호흡 중 리터 분해속도가 차지하는 비율은 식물 지하부의 생장이 활발해지는 5-6월에는 4.3%로 감소하였으며 리터의 생산량이 증가하는 11- 12월에는 23.5%로 증가하였다. 회귀분석결과 리터 분해속도와 토양호흡과는 r²= 0.63의 상관관계를 가지고 있었다.

• East Asian mathematical journal
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• 제37권3호
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• pp.295-305
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• 2021

In this paper, we analyze the efficiency of a domain decomposition method for the two-dimensional telegraph equations. We formulate the theoretical spectral radius of the iteration matrix generated by the domain decomposition method, because the rate of convergence of an iterative algorithm depends on the spectral radius of the iteration matrix. The theoretical spectral radius is confirmed by the experimental one using MATLAB. Speedup and operation ratio of the domain decomposition method are also compared as the two measurements of the efficiency of the method. Numerical results support the high efficiency of the domain decomposition method.

• The Korean Journal of Ecology
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• 제4권1_2호
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• pp.38-51
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• 1981

The present investigation was estimated the effect of temperature, precipitatiion, and time on the decomposition of litters with litter bags of Pinus densiffora and Quercus mongolica at Gure where elevation in 50m, and at Nogodan where elevation in 1300m on Mt. Jiri. As the above results, decomposition model was proposed to relation of the environmental conditions. And was investigated the production and decomposition of litters from the stands of various forest communities in Kwangneung, Mt. Jiri and Mt. Halla. The results are as follows; The models for the decay of organic carbon (C) was as follows: $C=Coe^{-Kt}$ (limiting factor;time) $C=Coe^{-K'te}$ (limiting factor;tempedrature) $C=Coe^{-KnP}$ (limiting factor:precipitation) As observed in litter bag method, the decomposition rate of litter in Pinus densiflora was slower than that of Quercus mongolica. The higher elevation, the slower decomposition rate. The decomposition of litters at Gure where elevation in 50m was equally influenced by temperature and precipitation. But at Nogodan where elevation in 1300m was much inflenced by precipitation. The decay constant of litters was larger in hardwood forest than in coniferous forest. In the same species, the more elevatiion, the less decomposition constant. The time required for the decay of 50%, 95^, 99% of the accumulated litters in the forest floor were faster in hardwood forest than in coniferous forest. In the same species, the higher elevatiion, the longer time required.

• The Korean Journal of Ecology
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• 제17권3호
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• pp.311-318
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• 1994

치화화 사막에서 몇 가지 식물 뿌리의 분해율과 분해 과정에 따른 질소함량의 변화를 조사하였다 (1986년 10월 ~ 1990년 4월). 뿌리의 분해는 리그닌 함량과 역상관 관계를 보였다(r=-0.84, n=5, p<0.05). 1년생 광엽초본인 Baileya multiradiata의 분해율이 가장 높았고 다년생 협엽 초본인 Panicum obtusum의 분해율이 가장 낮았다. 지역에 따른 분해율은 playa에서 가장 낮았다. Baileya multiradiata를 제외하고 모두 분해 초기에 질소의 무기화가 있은 다음 질소의 부동화가 나타났다. Baileya multirdiata의 뿌리는 분해 초기부터 질소함량이 계속 증가하는 것으로 나타났다. 다년생 협엽초본 뿌리의 리그닌 함량은 광엽초본 뿌리의 리그닌 함량보다 높았다.

• Journal of Ecology and Environment
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• 제34권4호
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• pp.401-410
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• 2011

We assayed the effects of simulated acid rain on the mass loss, $CO_2$ evolution, dehydrogenase activity, and microbial biomass-C of decomposing Sorbus alnifolia leaf litter at the microcosm. The dilute sulfuric acid solution composed the simulated acid rain, and the microcosm decomposition experiment was performed at 23$^{\circ}C$ and 40% humidity. During the early decomposition stage, decomposition rate of S. alnifolia leaf litter, and microbial biomass, $CO_2$ evolution and dehydrogenase activity were inhibited at a lower pH; however, during the late decomposition stage, these characteristics were not affected by pH level. The fungal component of the microbial community was conspicuous at lower pH levels and at the late decomposition stage. Conversely, the bacterial community was most evident during the initial decomposition phase and was especially dominant at higher pH levels. These changes in microbial community structure resulting from changes in microcosm acidity suggest that pH is an important aspect in the maintenance of the decomposition process. Litter decomposition exhibited a positive, linear relationship with both microbial respiration and microbial biomass. Fungal biomass exhibited a significant, positive relationship with $CO_2$ evolution from the decaying litter. Acid rain had a significant effect on microbial biomass and microbial community structure according to acid tolerance of each microbial species. Fungal biomass and decomposition activities were not only more important at a low pH than at a high pH but also fungal activity, such as $CO_2$ evolution, was closely related with litter decomposition rate.

• 한국환경과학회지
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• 제14권9호
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• pp.835-842
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• 2005

The three-dimensional eco-hydrodynamic model was applied to estimate the physical process in terms of COD (chemical oxygen demand) and net supply(or decomposition) rate of COD in Kamak Bay to find proper management plan for oxygen demanding organic matters. The estimation results of the physical process in terms of COD showed that transportation of COD is dominant in surface level while accumulation of COD is dominant in bottom level. In the case of surface level, the net supply rate of COD was 0 -0.50 mg/m2/day. The net decomposition rate of COD was 0 -0.04 mg/m2/day in middle level(3 -6m) and 0.05 -0.1 5 mg/m2/day in bottom level(6m -bottom). These results indicates that the biological decomposition and physical accumulation of COD are occurred predominantly at the northern part of bottom level. Therefore, it is important to consider both allochthonous and autochthonous oxygen demanding organic matters in the region.

• 조명전기설비학회논문지
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• 제25권4호
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• pp.65-70
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• 2011

Perfluorocompounds (PFCs) gases were decomposed by gliding arc plasma generated by AC pulse power. $N_2$ gas of 10 LPM flow rate and $H_2$ gas of 0.5 LPM were introduced into the gliding arc plasma generated between a pair of electrodes with SUS 303 material, and the PFCs gases were injected in the plasma and thereby were decomposed. The PFCs gas-decomposition-characteristics through the gliding arc plasma were analyzed by FT-IR, where pure $N_2$ and $H_2$-added $N_2$ environment were used to generate the gliding arc plasma. The PFCs gas-decomposition-properties were changed by electric power for gliding arc plasma generation and the H2 gas addition was effective to enhance the PFCs decomposition rate.

• 약학회지
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• 제28권6호
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• pp.299-303
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• 1984

In order to eluciate the effect of humidity and organic solvent on the decomposition of carbamide peroxide, the kinetic study was carried out. The carbamide peroxide was prepared from urea and 30%-hydrogen peroxide. The accelerated stability analysis for carbamide peroxide crystal in various relative humidity, and for 10%-carbamide peroxide solution of organic solvents were investigated. Both humidity and temperature were important factors influencing the decomposition rate of carbamide peroxide crystal. The higher the humidity and temperature, the greater was the reaction rate. The breakdown rate of crystal was observed as an apparent zero-order, and was faster than the rate of decomposition in dilute propylene glycol, glycerine or sorbitol solutioos which were measured as an apparent first-order reaction. The more dilute to 10% the organic solvents of 10%-carbamide peroxide, the slower was breakdown rate. It is, therefore, useful in the aspects of stability and economics to substitute solvent of carbamide peroxide topical solution (USP XXI) with 10%-propylene glycol or glycerine instead of anhydrous glycerine.

• 한국잠사곤충학회지
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• 제40권2호
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• pp.163-168
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• 1998

Hydrolysis rate and activation energy of Antheraea pernyi silk fiber treated with HCI were examined. Thermal decomposition temperature and surface morphology were also investigated by using differential scanning calorimeter and scanning electron microscope. As the concentration of hydrochloric acid and the treatment temperature increased, the hydrolysis occurred more rapidly. The activation energy of Antheraea pernyi, 74.0 kJ/mol, was higher than that of Bombyx mori, 58.1 kJ/mol. As the concentration of hydrochloric acid increases, the activation energy of Antheraea pernyi decreased from 74.0 kJ/mol to 62.0 kJ/mol. The shape of acid-resistance fraction of Antheraea pernyi became more distroyed and was transformed from fiber to powdered form with an increase of hydrolysis rate. The thermal decomposition temperature of Antheraea pernyi was 360.8$^{\circ}C$ until the hydrolysis rate was 81.8 wt%, but ti decreased to 347.0$^{\circ}C$ when the hydrolysis rate was 93.8 wt%.

• Journal of Ecology and Environment
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• 제43권4호
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• pp.376-384
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• 2019

Background: Nutrient release during litter decomposition was investigated in Vitex doniana, Terminalia avecinioides, Sarcocephallus latifolius, and Parinari curatellifolius in Makurdi, Benue State Nigeria (January 10 to March 10 and from June 10 to August 10, 2016). Leaf decomposition was measured as loss in mass of litter over time using the decay model W_t/W₀ = e-^{kd t}, while $Kd=-{\frac{1}{t}}In({\frac{Wt}{W0}})$ was used to evaluate decomposition rate. Time taken for half of litter to decompose was measured using T₅₀ = ln ²/k; while nutrient accumulation index was evaluated as $NAI=(\frac{{\omega}t\;Xt}{{\omega}oXo})$. Results: Average mass of litter remaining after exposure ranged from 96.15 g, (V. doniana) to 78.11 g, (S. lafolius) in dry (November to March) and wet (April to October) seasons. Decomposition rate was averagely faster in the wet season (0.0030) than in the dry season (0.0022) with P. curatellifolius (0.0028) and T. avecinioides (0.0039) having the fastest decomposition rates in dry and wet seasons. Mean residence time (days) ranged from 929 to 356, while the time (days) for half the original mass to decompose ranged from 622 to 201 (dry and wet seasons). ANOVA revealed highly significant differences (p < 0.01) in decomposition rates and exposure time (days) and a significant interaction (p < 0.05) between species and exposure time in both seasons. Conclusion: Slow decomposition in the plant leaves implied carbon retention in the ecosystem and slow release of CO₂ back to the atmosphere, while nitrogen was mineralized in both seasons. The plants therefore showed effectiveness in nutrient cycling and support productivity in the ecosystem.