• The Korean Journal of Mycology
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• v.35 no.1
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• pp.37-42
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• 2007

The mushroom Lentinus lepideus was used to produce mycelial as well as soluble polysaccharides in bioreactor cultures. To determine optimal submerged culture conditions, both growth characteristics and water soluble polysaccharides production were compared among four different types of bioreactor and culture conditions. For the production of mycelial biomass, the following bioreactors were proven to be effective in decreasing order: an external-loop type air-lift bioreactor (ETAB; 7g/l), a balloon type air bubble bioreactor (BTBB; 6.2g/l), a stirrer type bioreactor (STB; 6g/l), and a column type air bubble bioreactor (CTBB; 5g/l). Maxiaml production of water soluble exopolysaccharides (EPS; 0.62g/l) and endopolysaccharides (PPS; 7.7%) could also be obtained from BTBB. The mycelial biomass increased with increase in glucose concentration from 15g/l to 75g/l in the media. In contrast, PPS contents in the cells decreased with increase in glucose concentration in the media, showing the highest PPS content (7%) at 15g/l. Among different medium feeding types, fed-batch culture based on concentration control in media (10g/l) produced higher mycelia than fed-batch culture based on volume control of media (5.8g/l) or batch culture (3.4g/l). EPS production was also higher in fed-batch culture based on medium concentration control than that in other feeding types.

• Journal of Korea Foresty Energy
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• v.22 no.2
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• pp.54-59
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• 2003

Recently, densified pellet fuel from wood biomass is widely used at North America and Europe as a regenerable and clean carbon neutral bioenergy. High-pressure compaction of sawdust of Hyunsasi-poplar (Populus alba ${\times}$ P. glandulosa) to form a densified fuel was studied. Calorific and elemental analysis were carried out to assess Hyunsasi-poplar clones as fuels. Hot-press process was adopted for compaction of sawdust and compaction was performed under temperature from 100 to 180$^{\circ}C$, at pressure of 250 to 1000 kgf/$\textrm{cm}^2$, and for 2.5 to 10 minutes. Densified fuels were evaluated by its oven-dry density and fines after 5-minute shaking test. The target density and fines of densified fuels were over 1.2 g/$\textrm{cm}^2$ and below 0.5%, respectively. When the press-temperature is over 160$^{\circ}C$, densified fuels with density eve. 1.2 g/$\textrm{cm}^2$ and with fines below 0.5% can be produced. And the pressure over 750 kgf/$\textrm{cm}^2$ was effective for this production. It was found that the optimum press condition for preparation of densified fuel was 180$^{\circ}C$ -1000 kgf/$\textrm{cm}^2$ minutes.

• Clean Technology
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• v.22 no.4
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• pp.250-257
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• 2016

As an attempt to replacing petroleum-based chemicals with bio-based ones, synthesis of furfural from biomass-derived xylose attracts much attention in recent days. Conventionally, furfural from xylose has been produced via the utilization of highly corrosive, toxic, and environmentally unfriendly mineral acids such as sulfuric acid or hydrochloric acid. In this study, microwave-assisted biphasic reaction process in the presence of novel bio-based heterogeneous acid catalysts was developed for the eco-benign and effective synthesis of furfural from xylose. The microwave was irradiated for reaction acceleration and a biphasic system consisting of $H_2O$ : MIBK (1 : 2) was designed for continuous extraction of furfural into the organic phase in order to reduce the undesired side products formed by decomposition/condensation/oligomerization in the acidic aqueous phase. Moreover, sulfonated amorphous carbonaceous materials were prepared from wood powder, the most abundant lignocellulosic biomass. The prepared catalysts were characterized by FT-IR, XPS, BET, elemental analysis and they were used as bio-based heterogeneous acid catalysts for the dehydration of xylose into furfural more effectively. For further optimization, the effect of temperature, reaction time, water/organic solvent ratio, and substrate/catalyst ratio on the xylose conversion and furfural yield were investigated and 100% conversion of xylose and 74% yield of furfural was achieved within 5 h at $180^{\circ}C$. The bio-based heterogeneous acid catalysts could be used three times without any significant loss of activity. This greener protocol provides highly selective conversion of xylose to furfural as well as facile isolation of product and bio-based heterogeneous acid catalysts can alternate the environmentally-burdened mineral acids.

• Journal of Life Science
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• v.22 no.9
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• pp.1237-1242
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• 2012

The use of biological-activated carbon (BAC) processes in water treatment involves biofiltration, which maximizes the bacteria's capabilities to remove organic matter. In this study, the distribution of the bacterial community was assessed in response to different types of BAC processes applied downstream in the Nakdong River. The bacterial biomass and activity were $1.20{\sim}34.0{\times}10^7$ CFU/g and 0.61~1.10 mg-C/$m^3{\cdot}hr$ in coal-based BAC, respectively. The attachment of the bacterial biomass and the removal efficiency of the organic carbon were greatest with the coal-based activated carbon. The bacteria attached to each activated carbon material were detected in the order of Pseudomonas genus, Chryseomonas genus, Flavobacterium genus, Alcaligenes genus, Acinetobacter genus, and Spingomona genus. Pseudomonas cepacia was the dominant species in the coal-based materials, and Chryseomonas luteola was the dominant species in the wood-based material.

• Tuberculosis and Respiratory Diseases
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• v.77 no.3
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• pp.124-131
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• 2014

Background: Bronchial anthracofibrosis (BAF), which is associated with exposure to biomass smoke in inefficiently ventilated indoor areas, can take the form of obstructive lung disease. Patients with BAF can mimic or present with an exacerbation of chronic obstructive pulmonary disease (COPD). The purpose of the current study was to investigate the prevalence of BAF in Korean patients with COPD exacerbation as well as to examine the clinical features of these patients in order to determine its clinical relevance. Methods: A total of 206 patients with COPD exacerbation were divided into BAF and non-BAF groups, according to computed tomography findings. We compared both clinical and radiologic variables between the two groups. Results: Patients with BAF (51 [25%]) were older, with a preponderance of nonsmoking women; moreover, they showed a more frequent association with exposure to wood smoke compared to those without BAF. However, no differences in the severity of illness and clinical course between the two groups were observed. Patients in the BAF group had less severe airflow obstruction, but more common and severe pulmonary hypertension signs than those in the non-BAF group. Conclusion: Compared with non-BAF COPD, BAF may be associated with milder airflow limitation and more frequent signs of pulmonary hypertension with a more severe grade in patients presenting with COPD exacerbation.

• Journal of the Korean Society of Industry Convergence
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• v.25 no.2_1
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• pp.149-159
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• 2022

Biomass is material that is comprehensive of carbonaceous materials from plants, crops, animals, and algae. It has been used as one of heating fuel since the beginning the emergence of human beings. Since biomass is regarded as carbon-neutral energy source, it has recently been attracting attention as an energy source that can replace fossil fuels. The most widely applied field is distributed power generation, and a method of generating electric power by driving an internal combustion engine with syngas produced by gasifier is chosen. While the composition of the syngas produced in gasifiers changes depending on the air flowing into the reactor, commercialized gasifiers so far do not control the air flowing into the reactor. When the inner pressure in reactor increases, the air sucked into the reactor is reduced. That change of amount of air makes the composition of syngas varied. Those variations of composition of syngas cause the incomplete combustion hence the power output of engine drops, which is a critical weakness of the gasification technology. In this paper, to produce the uniformly composed syngas, PID control is applied. The result was shown when the amount of air into the reactor is supplied with the constant amount using PID control, the standard deviation of caloric values of syngas is around 2[%] of its average value. Meanwhile the gasifier without PID control has the standard deviation of caloric values is around 7[%]. Therefore, Adopting PID control to supply constant air to the gasifier is highly desirable.

• Journal of Korean Society of Forest Science
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• v.85 no.2
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• pp.271-279
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• 1996

This study was conducted to find out the appropriate rates of mixed-seeding of native woody and herb species. It was carried out in greenhouse from 1994 to 1995. The early days germination individuals were $60no./m^2$ in case of woody species for mixed seeding treatment and the treatments were fertilization, soil surface treatment, seeding amount. The investigation factors are the number of individuals of woody and herb species, biomass, height, number of tillers, etc. The mean individuals of Lespedeza bicolor and Amorpha frutzcosa were investigated $1.14no./m^2$, $0.496no./m^2$ in 1995, and Spiraea prunifolia var. simpliciflora and Alnus hirsuta were withering to death. In 1995, the Individuals of Oenothera odorata, Themeda triandra var. japonica, Cymbopogon tortilis var. goeringii, Miscanthus sinensis, Artemisia princeps var. orientalis, Lespedeza cuneata, and Arundinella hirta were investigated $5.06no./m^2$, $1,072no./m^2$, $0no./m^2$, $412.53no./m^2$, $88.6no./m^2$, $8.9no./m^2$, $57.46no./m^2$, respectively, in case of herb species. The height and biomass of Lespedeza bicolor and Amorpha fruticosa showed very fast growth, and those of Themeda triandra var. japonica, Miscanthus sinensis had a similar tendency. For the changes in woody species, according to the seeding amount, there was no significant relationship between species, but It was highly significant in 1995. In case of the herb species, the relationship between the number of individuals and seeding amount was significant for both 1994 and 1995. The most number of tiller was Miscanthus sinensis(21), and showed Themeda triandra var. japonica, Arundinella hirta in descending order. For the mixed seeding of wood and herb species, the number of individuals, height, biomass, tiller of herb species diminished as the seeding amount of herb species increased. It can be concluded that using Lespedeza bicolor and Amorpha fruticosa for woody species and like Arundinella hirta in herb species will be efficient for revegetation measures. It seems, therefore, that the plants of revegetation methods will be used to Lespedeza bicolor, Amorpha fruticosa and Arundinella hirta, and further study is needed on the seeding amount.

• Proceedings of the Korea Society for Energy Engineering kosee Conference
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• 2010.04a
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• pp.192-192
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• 2010

현재 산업과 과학의 발달로 인한 무분별한 화석연료의 사용은 에너지자원의 고갈과 환경오염의 문제를 야기시켜, 이의 해결을 위한 청정 신에너지에 대한 연구가 전 세계적으로 집중되고 있다. 이 중 바이오매스는 화석연료보다 비교적 높은 H/C 비를 갖기 때문에 신에너지인 수소 또는 Syngas를 생산하기 위한 가스화 특성이 우수한 특징을 가지고 있으며, 구성성분 내 중금속, 황, 질소를 거의 함유하지 않는 점에서 환경오염 저감과 동시에 대체 신에너지로써 각광을 받고 있다. 이에 본 연구에서는 목질계 바이오매스인 Wood pellet (미송)에 대하여 고정층 반응기를 이용하여 질소분위기하에서 온도 및 Steam/Biomass Ratio(이하 SBR) 조건에 따른 가스화 특성으로 고찰하는데 그 목적을 둔다. 온도의 영향에 대하여, 높은 온도 범위에서 수소 수율이 증가함을 알 수 있었다. SBR에 대한 영향으로서, 저온 (700, $800^{\circ}C$)에서는 SBR=1에서는 수소의 수율이 증가하였으나 SBR=2, 3에서 감소하는 것을 보였다. 하지만 $900^{\circ}C$에서는 SBR이 증가 할수록 수소의 수율이 증가하는 것으로 나타났다. 또한 볼륨비로 나타내었을 경우 $H_2/CO(vol/vol)$의 경우 $900^{\circ}C$, SBR=3에서 0.73%로 water gas shift reaction이 가장 잘 일어난 것을 확인했고, $H_2/CH_4(vol/vol)$의 경우 마찬가지로 위의 조건과 동일조건에서 2.59%로 steam reforming이 가장 잘 일어난 것을 확인할 수 있었다. 최종적으로 본 실험에서는 $900^{\circ}C$, SBR=3인 경우에 가장 높은 수소수율을 얻을 수 있으며, 이때 수소의 수율은 32.7 Vol%였다.

• Journal of the Korean Wood Science and Technology
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• v.35 no.6
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• pp.159-165
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• 2007

An extracellular xylanase from the brown-rot fungus Fomitopsis palustris grown on rice straw culture was purified to a single protein band. On SDS-PAGE, the molecular mass of purified enzyme was estimated to be about 43 kDa. The amino acid sequence of the proteolytic fragments showed high homology with fungal glycoside hydrolase family 10 xylanases. The $K_m$, $K_{cat}$ and $V_{max}$ for birch xylan were $31mg/m{\ell}$, $2.3{\times}10^4/min$ and 252.3 U/mg, respectively. The optimal activity of the purified xylanase from F palustris was observed at pH 4.0~5.0 and $70^{\circ}C$.

• Solar Energy
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• v.18 no.3
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• pp.161-167
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• 1998

The effects of some additives(black liquor, wood and lignin) on the conversion of coal and product were investigated in the lab-scale, high pressure reacting system around $375^{\circ}C$. The addition of lignin to coal during liquefaction significantly increased the depolymerization of coal and enhanced the quality of the liquid products. Coprocessing of wood and coal at $400^{\circ}C$ increased yield of liquid product about 8%, but higher temperature above $400^{\circ}C$ reduced liquid product due to increase of gas products. The addition of black liquor resulted in an enhancement in coal conversion yields, however, the observed increase is lower than that obtained in the presence of NaOH because lignin present in black liquor is not very effective due to the $OH^-$ presence.