• Journal of Life Science
• /
• v.23 no.9
• /
• pp.1170-1176
• /
• 2013

Essential oils have been used to treat psychophysiological disorders, but their effects on human electroencephalographic (EEG) activity have not been thoroughly investigated. We evaluated the effects of essential oil of Zizyphus jujuba seeds, a Korean folk medicine known as San-Jo-In, on human EEG activity. For this purpose, essential oil was extracted from San-Jo-In by the supercritical carbon dioxide extraction method. The effect of its inhalation on EEG activity was evaluated by measuring the EEG power spectrum (25 indices) in 20 healthy participants. The results of the EEG power spectrum indicated that the values of the theta wave decreased significantly (p<0.05) in the left (from 17.277 to $13.854{\mu}V$) and right parietal (from 15.324 to $13.020{\mu}V$) regions compared to the other regions. During the inhalation of San-Jo-In oil, the EEG spectrum values of fast alpha, relative gamma, and spectral edge frequency increased 50% compared to those before inhalation. The values of the fast alpha wave increased significantly (p<0.05) in the left prefrontal (from 0.063 to $0.085{\mu}V$), right prefrontal (from 0.064 to $0.085{\mu}V$), and left frontal (from 0.073 to $0.100{\mu}V$) regions following inhalation of the San-Jo-In essential oil. The changes in the EEG activities following inhalation of San-Jo-In suggest that the oil can improve psychological well-being by increasing attention and relaxation.

• The Korean Journal of Mycology
• /
• v.42 no.1
• /
• pp.57-63
• /
• 2014

This study was carried out to obtain morphological and physiological characteristics of ear mushrooms for an artificial cultivation. Eighteen strains were cultivated with bag culture and classified into mainly five groups such as brown, black, white, purple and others group. The highest yield was shown in 43007 strain as 98.3 g/bag and 43009, 43016, 43025 and 44035 strains were more than 60 g/bag. Among collected strains, 43007, 43009 and 43035 were selected in this study as superior strains. Three selected strains were investigated for optimal mycelial growth conditions. MCM and GPYM media were selected for the favorable culture medium. The carbon sources of 43007, 43009 and 43035 on mycelial growth were maltose, fructose and glucose, respectively and peptone was selected as a nitrogen source. Highest mycelial growth was observed when the C/N ratio was 10 for 43007 and 20 for 43009 and 43035.

• Journal of the Korean Geotechnical Society
• /
• v.30 no.2
• /
• pp.5-18
• /
• 2014

Depending on the underground load support mechanism, anchors are classified as friction anchors, bearing plate anchors and the recently developed combined friction-bearing plate anchors which combine the characteristics of both the friction and bearing plate type anchors. Even though numerous studies have been performed on bearing plate anchors, there were only few studies performed to observe the failure surface of bearing plate anchors. Furthermore most of the soil materials used on these tests were not real sand but carbon rods. In this study, sand was placed in the soil tank and laboratory tests were performed with bearing plate anchors installed with an embedment depth (H/h) ranging from 1~6. The variation in the pullout capacity and the behaviour of soil with the embedment depth (H/h) were observed. Ground deformation analysis program was also used to analyze soil displacement, zero extension direction, maximum shear strain contours. It was determined from the analysis of the results that at ultimate pullout resistance the deformation was 5 mm and the failure surface occurred in a narrower area when compared with results of the previous researches. It was also observed that the width of the fracture surface gradually becomes wider and expands up to the surface as the deformation increases from 10 mm to 15 mm.

• Journal of Mushroom
• /
• v.7 no.1
• /
• pp.9-21
• /
• 2009

This study was executed in an attempt to investigate a artificial requisites of fruitbody occurrence. Environmental requirements on habitat for fruitbody occurrence of collected cultures resulted in leading to $13-16^{\circ}C$ and 75% relative humidity, and requiring silt loam of soil texture which had more nutritional substances than a dry field. Optimal temperature was $25^{\circ}C$, medium PDB, and pH 5.0 in cultural conditions. Mannose required of 5% in ASI 59002, 59003, 59004, but 3% in ASI 59001 was selected as optimum carbon source. The substrates stimulating sclerotium formation were cotton waste, or cotton waste + oak sawdust (mixture ratio of 8:2), which had 20% additive of wheat barn respectively. Sclerotium was formed well in the substrate adjusted chemical properties by applying 2% of calcium sulfate. Sclerotium formation was the most effective in the treatment of peat moss + oak sawdust (mixture ratio of 5:5) + 30% of wheat barn.

• Journal of Mushroom
• /
• v.9 no.4
• /
• pp.139-144
• /
• 2011

This study was carried out to investigated mixing ratio of redginseng marc using organic waste resource for production cost-reduction of oyster mushroom. Redginseng marc were examined as substitute of cottonseed meal which was primary nutritive material of mushroom growing substrate. Total nitrogen and carbon source of redginseng marc was 45% and 2.7%, respectively and C/N ratio was 16.7. Total nitrogen source and pH of substrate mixed with redginseng marc was 4.6~4.9 and 2.5~2.8, respectively. The contents of $P_2O_5$, $K_2O$ and MgO were decreased by increasing redginseng marc, but increased at the 20% redginseng marc. The contents of CaO was increased by increasing redginseng marc, but there was no significant difference in $Na_2O$ content. The more mixing ratio of redginseng marc was increased in column test, the more mycelial growth growed slowly. Yields of fruiting body was no significant difference compared with control group by adding of 10~50% redsingeng marc instead of cottonseed meal, but decreased sharply at only 20% redsingeng marc without cottonseed meal. The L value of pileus by increasing redginseng marc decreased during mushroom harvest, but there was no significant difference in the a-value and the b-value.

• Journal of Korean Society of Environmental Engineers
• /
• v.36 no.3
• /
• pp.198-205
• /
• 2014

The present paper investigates the leaching property of coal fly ash (FA) using distilled water as solvent and its performance of mineral carbonation. The highest leaching efficiency is obtained at 100 min after leaching begins and the overall leaching efficiencies of Ca and Na via five consecutive leachings were calculated to be 25.37% and 7.40%, respectively. In addition, because $Ca(OH)_2$ produced during the leaching reacts with $SiO_2$ which is the major component of FA, the Pozzolanic reaction may occur and thus reduces leaching efficiency. Total carbonation capacity of FA by absorbing $CO_2$ into FA leachates is 6.08 mg $CO_2/g$ FA and the contribution of alkali substances such as Ca, Na, Mg and K to this value is calculated to be 5.19 mg $CO_2/g$ FA. Carbonation efficiencies of Ca and Na based on leachates are 85.62% and 77.70%, respectively. On the other hand, the ratios of Ca and Na in raw FA to participate in carbonation are calculated to be 9.04% and 5.26%, respectively.

• Journal of Adhesion and Interface
• /
• v.7 no.1
• /
• pp.16-22
• /
• 2006

In this work, the effect of cure temperature and time on the thermal stability and the exothermic cure reaction peak of a waterborne resol-type phenol-formaldehyde resin, which may be used for preparing phenolic sheet molding compounds (SMC), has been investigated using a thermogravimetric analyzer and a differential scanning calorimeter. The weight loss of waterborne phenol-formaldehyde resin was mainly occurred at three temperature stages: near $200^{\circ}C,\;400^{\circ}C$, and $500^{\circ}C$. The carbon yield at $750^{\circ}C$ for the cured resin was about 62%~65%. Their thermal stability increased with increasing cure temperature and time. Upon cure, the exothermic reaction was taken placed in the range of $120^{\circ}C{\sim}190^{\circ}C$ and the maximum peak was found in between $165^{\circ}C$ and $170^{\circ}C$. The shape and the maximum of the exothermic curves depended on the given cure temperature and time. To remove $H_2O$ and volatile components, the uncured resin needed a heat-treatment at $100^{\circ}C$ for 60 min at least prior to cure or molding. Curing at $130^{\circ}C$ for 120 min made the exothermic peak of waterborne phenol-formaldehyde resin completely disappeared. And, post-curing at $180^{\circ}C$ for 60 min further improved the thermal stability of the cured resin.

• Korean Journal of Microbiology
• /
• v.51 no.3
• /
• pp.263-270
• /
• 2015

A bacterial strain producing extracellular mannanases was isolated from soil of chestnut tree farm located in Gongju city of Korea by enrichment culture using Avicel as a carbon source. 16S rDNA sequence of the isolate YB-43 was highly homologous to those of genus Cellulosimicrobium strains with sequence similarities of above 99.6%. Mannanase productivity was significantly increased when the Cellulosimicrobium sp. YB-43 was grown in the presence of locust bean gum (LBG) or konjac. The mannanases were partially purified to be mannanase A (ManA) and mannanase C (ManC) by DEAE-Sepharose column and Q-Sepharose column chromatography from the culture filtrate of Cellulosimicrobium sp. YB-43 grown in LB medium supplemented with 0.7% LBG for 24 h. The partially purified ManA showed the highest activity at $55^{\circ}C$ and pH 6.5, while ManC activity was optimal at $65^{\circ}C$ and pH 7.5. ManA was stable up to $40^{\circ}C$ for 1 h, but ManC activity decreased significantly even after 1 h at $20^{\circ}C$. ManA and ManC showed difference from each other according to their substrate specificities and predominant products resulting from the mannanase hydrolysis for mannooligosaccharides. As a result, Cellulosimicrobium sp. YB-43 was found to produce two different kinds of mannanases.

• International Journal of Highway Engineering
• /
• v.13 no.3
• /
• pp.93-102
• /
• 2011

The Korean government recently has focused on variety of policies to promote the use of bikes to control the emission of carbon. However, bike facilities with no regard to the safety and comfort of bike drivers has made inefficient bike roads. Also, the accidents related to bikes have increased rapidly. This study proposes the proper types of the bike roads considering land use and bike driver characteristics. The elements classifying the bike driver characteristics are driven through oneway ANOVA and cluster analysis. It is found that the types of the bike roads can be classified by the ratio of child and elderly bikers and the ratio of heavy trucks. Also, the each type is characterized by the land use types such ad residential, commercial and industrial areas through cluster analysis. According to the results of the cluster analysis, installation of bike roads in residential area needs to consider convenience and safety simultaneously. It is also found that convenience should be the most considerable factor in commercial area. Lastly, safety should be considered in industrial area. Recommended methodology and bike road type based on the land use and bike driver's characteristics can be useful to develop bike-friendly environments and increase mode share of bikes.

• Asian Journal of Atmospheric Environment
• /
• v.5 no.4
• /
• pp.237-246
• /
• 2011

To explore the sources of carbonaceous material in the airborne particulate matter (PM), comprehensive PM sampling was performed (3 to 14 January 2010) at a traffic hot spot site (HS), Farm Gate, Dhaka using several samplers: AirMetrics MiniVol (for $PM_{10}$ and $PM_{2.5}$) and MOUDI (for size fractionated submicron PM). Long-term PM data (April 2000 to March 2006 and April 2000 to March 2010 in two size fractions ($PM_{2.2}$ and $PM_{2.2-10}$) obtained from two air quality-monitoring stations, one at Farm Gate (HS) and another at a semi-residential (SR) area (Atomic Energy Centre, Dhaka Campus, (AECD)), respectively were also analyzed. The long-term PM trend shows that fine particulate matter concentrations have decreased over time as a result of government policy interventions even with increasing vehicles on the road. The ratio of $PM_{2.5}/PM_{10}$ showed that the average $PM_{2.5}$ mass was about 78% of the $PM_{10}$ mass. It was also found that about 63% of $PM_{2.5}$ mass is $PM_1$. The total contribution of BC to $PM_{2.5}$ is about 16% and showed a decreasing trend over the years. It was observed that $PM_1$ fractions contained the major amount of carbonaceous materials, which mainly originated from high temperature combustion process in the $PM_{2.5}$. From the IMPROVE TOR protocol carbon fraction analysis, it was observed that emissions from gasoline vehicles contributed to $PM_1$ given the high abundance of EC1 and OC2 and the contribution of diesel to $PM_1$ is minimal as indicated by the low abundance of OC1 and EC2. Source apportionment results also show that vehicular exhaust is the largest contributors to PM in Dhaka. There is also transported $PM_{2.2}$from regional sources. With the increasing economic activities and recent GDP growth, the number of vehicles and brick kilns has significantly increased in and around Dhaka. Further action will be required to further reduce PM-related air pollution in Dhaka.