• Microbiology and Biotechnology Letters
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• v.4 no.3
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• pp.99-104
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• 1976

Experiments were carried out to establish the effects of acids in neutralization after alkaline treatment of rice straw, with which cellulosic single cell protein can be produced by cellulose utilizing bacteria, Cellulomonas flavigena KIST 321, previously isolated by authors. Following results were obtained. 1. Rice straw as carbon source was pretreated with 10 volumes of 1 normality of NH$_4$OH or NaOH(NaOH/substrate：40％, and then washed with water or neutralized with H$_3$PO$_4$, H$_2$SO$_4$, HCl and CH$_3$COOH. Among the above mentioned methods, neutralization with H$_3$PO$_4$after alkaline treatment was proved to be the most effective on its digestibility and SCP production. Dry cell 12.28g/$\ell$ and 78％ digestibility were obtained. 2. When rice straw was treated with NaOH solution, the result suggested that the productibity of cell-mass was attained on treatment of rice straw with 6％ of NaOH (NaOH/substrate ratio) for 15～24hrs at room temperature. 3. When rice straw was treated with NaOH, a volume of water to substrate is adequate by two or three fold and the amount of NaOH can be economized up to 5％ for the weight of rice straw. 4. The steaming of rice straw at 121$^{\circ}C$ for 30min. in alkaline treatment of rice straw gave the similiar effectiveness to that at room temperature for 15～24hrs. and accelerated the sterilization of the substrate. 5. Finally, the level of inorganic phosphate in a medium was investigated. 11.2g of dry cell was produced at the concentration of 0.2％, phosphate (phosphorous level 0.04％) in medium even though treated rice straw was neutralized with HCI instead of H$_3$PO$_4$, and 12.2g/$\ell$ at the concentration of 0.3％ phosphate (phosphorous 0.04％) on neutralization with H$_2$SO$_4$.

• New & Renewable Energy
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• v.18 no.4
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• pp.1-11
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• 2022

Landfill gas (LFG) generation characteristics in a construction waste landfill zone (block E) and mixed landfill zone (block A) were analyzed. During the period from October 2018 to April 2022, a total of 936×10³ and 1,001×10³ tons of waste were disposed in block E and block A, respectively. Out of this, 27.1% and 55.6% were biodegradable waste in block E and block A, respectively. The landfill masses of the two blocks were converted to be comparable. Then, the biodegradable waste and organic carbon were estimated by element analysis, biodegradable carbon by biochemical methane potential experiment (DC), and sulfate ion by acid decomposition. Results showed that biodegradable waste, organic carbon, biodegradable carbon, and sulfate ions in block A were 2.1, 1.6, 5.2, and 0.4 times greater than those in block E, respectively. The amount of LFG generated by block A was 4.8 times greater than that by block E. The average concentrations of methane (CH₄) were 60.8% and 60.9% in block E and block A, respectively, which were unrelated to the nature of disposed waste. The average concentrations of hydrogen sulfide (H₂S) were significantly high in block E (4,489 ppm) and block A (8,478 ppm). As the DC/SO₄^2- of block E and block A were 0.35 and 4.56, respectively, increase in DC/SO₄^2- caused increase in not only the total amount but also the concentration of H₂S generated.

• The Korean Journal of Pesticide Science
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• v.14 no.4
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• pp.440-445
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• 2010

This study was carried out to investigate the toxicities of five registered insecticides to the Lycorma delicatula nymphs and adults. Insecticidal activities were evaluated by testing systemic and residual effects in the laboratory, and control efficacy in the vineyard. For the 3rd nymphal instars and adults, etofenprox+diazinon, chlorpyrifos, etofenprox, dinotefuran and imidacloprid showed perfect insecticidal activity. The systemic effects of dinotefuran and etofenprox+diazinon on grape roots at half concentration were showed the adult mortality of 82.2% and 84.4%, respectively. Chlorpyrifos at recommended concentration was showed mortality of 86.0%. The leaf systemic effects at recommended and half concentrations of all insecticides except dinotefuran were lower than 65% but the mortality at double concentration of chlorpyrifos, dinotefuran, etofenprox were more than 82%. The residual effect between etofenprox+diazinon and dinotefuran at recommended and double concentrations were 100% at 14 days after treatment, the other insecticides have low efficacy. All the four insecticides showed 87% control value on nymphs in the field test and adults appeared more than 96% control value st and adinotefuran, etofenprox+diazinon, however, the other insecticides decreased to 59.1 % and 61.2%. Therefore, dinotefuran and etofenprox+diazinon showing high systemic effects to roots and long residual effects to leafs have high control efficacies.

• Korean Journal of Materials Research
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• v.24 no.9
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• pp.451-457
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• 2014

We developed a high-performance methane gas sensor based on a $SnO_2$ hollow hemisphere array structure of nano-thickness. The sensor structures were fabricated by sputter deposition of Sn metal over an array of polystyrene spheres distributed on a planar substrate, followed by an oxidation process to oxidize the Sn to $SnO_2$ while removing the polystyrene template cores. The surface morphology and structural properties were examined by scanning electron microscopy. An optimization of the structure for methane sensing was also carried out. The effects of oxidation temperature, film thickness, gold doping, and morphology were examined. An impressive response of ~220% was observed for a 200 ppm concentration of $CH_4$ gas at an operating temperature of $400^{\circ}C$ for a sample fabricated by 30 sec sputtering of Sn, and oxidation at $800^{\circ}C$ for 2 hr in air. This high response was enabled by the open structure of the hemisphere array thin films.

• 한국연소학회:학술대회논문집
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• 2014.11a
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• pp.33-36
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• 2014

Gasification of biomass produces syngas containing CO, $H_2$ and/or $CH_4$, which can then be converted into energy or value-added fuels. One of key issues for efficient gasification is to minimize tar concentration in the syngas for use in a final conversion device such as gas engine. This study investigated the decomposition of primary tar by catalytic cracking using char as catalyst, of which the feature can be integrated into a fixed bed gasifier design. The pyrolysis vapor containing tar from pyrolysis of wood at $500^{\circ}C$ was passed through a reactor filled with or without char at $800^{\circ}C$ for a residence time of 1, 3 or 5 sec. Then, the condensable vapor (water and tar) and gases were analyzed for the yields and elemental composition. Four types of char particles with different microscopic surface area and pore size distribution: wood, paddy straw, palm kernel shell and activated carbon. The results were analyzed for the mass and carbon yields of tar and the composition of product gases to conclude the effects of char types and residence time.

• 한국생물공학회:학술대회논문집
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• 2003.10a
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• pp.404-408
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• 2003

In this study, hydrogen gas produced by anaerobic mocrobial at anaerobic condition. To maintain the high MLSS concentration, anaerobic sludge was transformed to granular sluge by adding both high molecular cationic polymer(M.W>5,000,000) and silica sol. Hydrogen production was easily distributed, which seemed caused by methane producing microbial. Even low pH control(pH<5.5) was not the effective mean to block methane producing microbial. To decrease of $H_2$ production was closely related with the inclose of $CH_4$ production. Other mean expect for pH control must be devised for the efficient $H_2$ production.

• 한국생물공학회:학술대회논문집
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• 2003.04a
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• pp.339-342
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• 2003

In this study , hydrogen gas produced by anaerobic mocrobial at anaerobic condition. To maintain the high MLSS concentration, anaerobic sludge was transformed to granular sluge by adding both high molecular cationic polymer(M.W.>5,000,000) and silica sol. Hydrogen production was easily distributed, which seemed caused by methane producing microbial. Even low pH control(pH<5.5) was not the effective mean to block methane producing microbial. To decrease of $H_2$ production was closely related with the inclose of $CH_4$ production. Other mean expect for pH control must be devised for the efficient $H_2$ production.

• Food Science and Biotechnology
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• v.16 no.3
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• pp.457-462
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• 2007

Histone acetyltransferase (HAT) is a family of enzymes that regulate histone acetylation. Dysfunction of HAT plays a critical role in the development of cancer. Here we have screened the various plant extracts to find out the potent HAT inhibitors. The bellflower (Platycodon grandiflorum) root have exhibited approximately 30% of the inhibitory effects on HAT activity, especially p300 and CBP (CREB-binding protein) at the concentration of $100\;{\mu}g/mL$. The cell viability was decreased approximately 52% in LNCaP cell for 48 hr incubation. Furthermore, mRNA level of 3 androgen receptor target genes, PSA, NKX3.1, and TSC22 were decreased with bellflower root extract treatment ($100\;{\mu}g/mL$) in the presence of androgen. In ChIP assay, the acetylation of histone H3 and H4 in PSA promoter region was dramatically repressed by bellflower root treatment, but not TR target gene, Dl. Therefore, the potent HAT inhibitory effect of bellflower root led to the decreased transcription of AR target genes and prostate cancer cell growth with the repression of histone hyperacetylation.

• Proceedings of the KSRS Conference
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• 2002.10a
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• pp.373-377
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• 2002

The Measurement of Pollution in the Troposphere (MOPITT) instrument is an eight-channel gas correlation radiometer launched on the Earth Observing System (EOS) Terra spacecraft in 1999. Its main objectives are to measure carbon monoxide (CO) and methane (CH4) concentrations in the troposphere. This work analyzes tropospheric carbon monoxide distributions using MOPITT data in East Asia and compared ozone distributions. In general, seasonal CO variations are characterized by a spring peak and decreased in the summer. Also, this work revealed that the seasonal cycles of CO are spring maximum and summer minimum with averaged concentrations ranging from 118ppbv to 170ppbv. The CO monthly means show a similar profiles to those of O3. This fact clearly indicates that the high concentration of CO in spring is caused by two possible causes: the photochemical CO production in the troposphere, transport of the CO in the northeast Asia. The CO and O3 seasonal cycles in northeast Asia are influenced extensively by the seasonal exchange of the different types of air mass due to the Asian monsoon. The continental air masses contain high concentrations of O3 and CO due to higher continental background concentrations and sometimes due to the contribution of regional pollution. In summer the transport pattern is reversed. The Pacific marine air masses prevail over Korea, so that the marine air masses bring low concentrations of CO and O3, which tend to give the apparent minimum in summer.

• Korean Journal of Microbiology
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• v.24 no.3
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• pp.276-287
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• 1986

Chlorella ellipsoidea were cultured in the media containing rifampicin for 7 days. Aliquot cells were taken out after the inoculation and at intervals during cultivation and growth rate of Chlorella cells was measured. In order to investigate the effect of rifampicin on the nucleic acid synthesis, nucleic acid and RNA polymerase were extracted from chloroplast isolated from these cells, and the contents of nucleic acid and activity of enzyme were measured to compared with those of the control. The inhibitory concentration of rifampicin on growth was 80 ppm. The DNA contents in chloroplasts isolated were decreased 60% to compared with control, whole cells were markedly decreased 70% by rifampicin. The contents of base in the RNA were decreased 46% by rifampicin in shole cell, and 77% of base contents were decreased in chloroplast. Rifampicin also inhibited the activity of RNA polymerase, therefore whole cell was decreased 10% of activity and chloroplasts were decreased 42% of activity.