• Journal of the Korean Wood Science and Technology
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• v.44 no.1
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• pp.19-29
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• 2016

The purpose of this study is to analyze the combustion and thermal properties in order to establish baseline data for the fire safety evaluation of imported wood. The combustion properties such as heat release rate, total heat release, gas yield, and mass loss were analyzed by the method of cone calorimeter test according to KS F ISO 5660-1 and thermogravimetric analysis (TGA). Analyzed species are five kinds of species as Merbau, Mempening, Garo Garo, Malas, and Dillenia. The heat released rate values showed the highest value of Malas as $375.52kW/m^2$, and Dillenia showed the lowest value as $133.30kW/m^2$. The data values were confirmed in the following order: Malas > Mempening > Garo Garo > Merbau > Dillenia. In case of the total heat release, it was measured in the following order: Mempening > Malas > Garo Garo > Merbau > Dillenia. The gas analysis results were that Dillenia showed the highest value of 0.034. Also, Mempening and Malas showed the lowest at 0.020 in the $CO/CO_2$. Min of mass reduction was shown as 74.79% Sargent cherry, on the other hand, Malas had a 83.52%. It showed a correlation between and of the CO and $CO_2$ generation and combustion characteristics of wood. The thermal decomposition temperature of the wood in the TGA were as follow that Merbau $348.07^{\circ}C$, Mempening $367.57^{\circ}C$, Garo Garo $350.59^{\circ}C$, Malas $352.41^{\circ}C$, Dillenia $364.33^{\circ}C$. The aim of this study is to determine the combustion properties of imported wood according to ISO 5660-1. And, based on the results of this study, we would proceed with further research for improving the fire safety of wood for construction.

• Tunnel and Underground Space
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• v.10 no.3
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• pp.430-440
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• 2000

A series of studies such as geological logging data analysis, detailed geological survey, rock mass evaluation, in-situ and laboratory tests, rock strength and mechanical properties of the rock were concerned. The stability of the slope were carried out inorder to design the pit slope and individual benches using the stereographic projection analysis and numerical methods in Roto Pit of Pasir coal field. The bedding plane was one of the major discontinuities in the Roto Pit and the dip of which is about 60$^{\circ}$ in the northern part and 83$^{\circ}$ in the southern part. The dip of bedding becomes steeper from north to south. The plane and toppling failures are presented in many slopes. In laboratory test the average uniaxial compressive strength of mudstone was 9MPa and that of weak sandstone was 10MPa. In-situ test showed that the rocks of Roto north mining area are mostly weak enough to be classified in grade from R2(weak) to R3(medium strong weak) and the coal is classified in grades from R1(Very weak) to R2(Weak). The detailed stability analysis were carried out on 4 areas of Roto north (east, west, south and north), and 2 areas of Roto south(east and west). In this paper, the minimum factor of safety was set to 1.2 which is a general criterion for open pit mines. Using the stereographic projection analysis and the limit equilibrium method, slope angles were calculated as 30∼36$^{\circ}$ for a factor of safety greater than 1.2. Then these results were re-evaluated by numerical analysis using FLAC. The final slope angles were determined by rational described above. A final slope of 34 degrees can guarantee the stability for the eastern part of the Roto north area, 33 degrees for the western part, 35 degrees for the northern part and 35 degrees for the southern part. For the Roto south area, 36 degrees was suggested for both sides of the pit. Once the pit slope is designed based on the stability analysis and the safety measures, the stability of slope should be checked periodically during the mining operations. Because the slope face will be exposed long time to the rain fall, a study such aspreventive measures against weathering and erosion is highly recommended to be implemented.

• Korean Journal of Organic Agriculture
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• v.17 no.2
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• pp.211-226
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• 2009

This experiment was conducted to investigate the effect of plant extracts, Chrysanthimum cinerariefolium and Melia azedarach to natural enemies and management of two spotted spider mite, Tetranychus urticae in organic strawberry fields in Jeonnam area. Plant extracts were highly toxic against Phytoseiulus persimilis, but low against Orius laevigatus. In the residual effect against Phytoseiulus persimilis, C. cinerariefolium showed lower level than M. azedarach which safe at least 1 day after spray. Emergence rates of parasitoids were about 40% at seven days after spray. Eretmocerus eremicus has very low emergence rate in treatment of M. azedarach, so it should release after spray of M. azedarach. To control of T. urticae C. cinerariefolium (CC) sprayed first and then sprayed C. cinerariefolium or M. azedarach (MA) for two and three times at a week interval. In the treatment of CC+MA and CC+CC+MA, the density of T. urticae was inhibited by 15th day but increased afterward. In CC+MA+CC, that of T. urticae inhibit from 8 days but also increased after I5th day. In case of spray M. azedarach (MA) first, the treatment of MA+CC, MA+MA+CC, MA+CC+MA suppressed T. urticae from the first day so the densy of T. urticae maintained low level to 30 days after spray. It suggested that M. azedarach should spray first and then alternative spray. When C. cinerariefolium sprayed before and behind to release of P. persimilis, the density of P. persimilis maintained unchanged but could not suppress T. urticae after 8 days which T. urticae increase time. When M. azedarach sprayed, the density of T. urticae rapidly decreased. It was accompanied with P. persimilis so T. urticae did not occur at 8 days after treatment.

• Korean Journal of Food Science and Technology
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• v.42 no.4
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• pp.383-389
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• 2010

The aim of this study was to determine the methylmercury (MeHg) levels in abyssal fish species. The MeHg in the fishes was extracted with hydrochloric acid and toluene and then purified using an L-cysteine solution. The extract was analyzed with a gas chromatography-electron capture detector (GC-${\mu}ECD$) with a thermon Hg-capillary column. The detection limit and the recovery of the method were 0.002 and 84.2-98.5% (mean, 93.4%), respectively. The MeHg content in 492 abyssal fishes ranged from 0.037 to 2.009 mg/kg. The levels of MeHg [range, mg/kg (mean)] were significantly dependent on fish species and presented as the following; 0.157-2.009 (0.546) in Scalloped hammerhead shark, 0.211-0.878 (0.501) in Blue shark, 0.121-0.993 (0.482) in Spiny dogfish, 0.243-0.658 (0.397) in Salmon shark, 0.074-1.958 (0.353) in Blacktip shark, 0.038-0.807 (0.302) in Southern hake, 0.099-0.511 (0.300) in Scorpion fish, and 0.037-0.133 (0.067) in Ling. The monitoring results showed that the estimated weekly intake of MeHg from sharks, Southern hake, and Ling were lower than the provisional tolerable weekly intake recommended by the Joint FAO/WHO expert committee on food additives.

• Korean Journal of Environment and Ecology
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• v.25 no.5
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• pp.649-657
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• 2011

This study had targeted the Manjong Junction~Hongchun interchange section of Jungang highway in order to analyze the efficiency and improvement of the highway wild-life fences. Being analyzed wild-life fence as an effective facility for the prevention of road-kill, it had founded that the wild animals did not jump over even the two layer guardrail, concrete barrier and noise barrier, fence for rock fall. For the section with high road-kill decrease effect after installing the wild-life fence, the effect was higher at wild-life fence with the height of 1.0m where the door had not been installed and the well connected points of road facility than the area with fence height of 1.5m. The road-kill decrease effect was also high at the well managed areas even if the door has not been installed. Also, road-kill had occurred by concentrating around the end of wild-life fence after installing the fence, Moreover road-kill had also occurred around the cutting section. The door of wild-life fence had higher amount of road-kill occurrence as the installation interval was closer. it was analyzed that the door management has a lot of effect on road-kill decrease. The fence for rock fall, two layer guardrail and concrete barrier having the effect of wild-life fence installed on the road would have to be installed by connecting with wild-life fences through proper facility improvement. Although the door should not be installed if possible, it should be installed as automatic door or gravity door to prevent the door from leaving the door open. An escape route has to be formed for the prompt escape away from the road for the animals entered through the ending section of the fence. The eco-corridor has to be made by restoring the soil layer of dual purpose eco-corridor forming a planting area. Also, the dead body after the accident has to be disposed to the outer section of the road immediately in order to prevent the secondary road-kill by the predator from the road-kill. The fence has to be installed as 500m or longer in both ways, in other words 1,000m or longer, from the targeted spot of minimum accident prevention while connecting up to the bridge or box culvert, etc that are next road facilities if possible to guide wild animals safely to the eco-corridor.

• The Journal of Korean Society for Radiation Therapy
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• v.26 no.2
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• pp.257-264
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• 2014

Purpose : Photoneutron dose in high-energy photon radiotherapy at linear accelerator increase the risk for secondary cancer. The purpose of this investigation is to evaluate the dose variation of photoneutron with different treatment method, flattening filter, dose rate and gantry angle in radiation therapy with high-energy photon beam ($E{\geq}8MeV$). Materials and Methods : TrueBeam $ST{\time}TM$(Ver1.5, Varian, USA) and Korea Tissue Equivalent Proportional Counter (KTEPC) were used to detect the photoneutron dose out of the high-energy photon field. Complex Patient plans using Eclipse planning system (Version 10.0, Varian, USA) was used to experiment with different treatment technique(IMRT, VMAT), condition of flattening filter and three different dose rate. Scattered photoneutron dose was measured at eight different gantry angles with open field (Field size : $5{\time}5cm$). Results : The mean values of the detected photoneutron dose from IMRT and VMAT were $449.7{\mu}Sv$, $2940.7{\mu}Sv$. The mean values of the detected photoneutron dose with Flattening Filter(FF) and Flattening Filter Free(FFF) were measured as $2940.7{\mu}Sv$, $232.0{\mu}Sv$. The mean values of the photoneutron dose for each test plan (case 1, case 2 and case 3) with FFF at the three different dose rate (400, 1200, 2400 MU/min) were $3242.5{\mu}Sv$, $3189.4{\mu}Sv$, $3191.2{\mu}Sv$ with case 1, $3493.2{\mu}Sv$, $3482.6{\mu}Sv$, $3477.2{\mu}Sv$ with case 2 and $4592.2{\mu}Sv$, $4580.0{\mu}Sv$, $4542.3{\mu}Sv$ with case 3, respectively. The mean values of the photoneutron dose at eight different gantry angles ($0^{\circ}$, $45^{\circ}$, $90^{\circ}$, $135^{\circ}$, $180^{\circ}$, $225^{\circ}$, $270^{\circ}$, $315^{\circ}$) were measured as $3.2{\mu}Sv$, $4.3{\mu}Sv$, $5.3{\mu}Sv$, $11.3{\mu}Sv$, $14.7{\mu}Sv$, $11.2{\mu}Sv$, $3.7{\mu}Sv$, $3.0{\mu}Sv$ at 10MV and as $373.7{\mu}Sv$, $369.6{\mu}Sv$, $384.4{\mu}Sv$, $423.6{\mu}Sv$, $447.1{\mu}Sv$, $448.0{\mu}Sv$, $384.5{\mu}Sv$, $377.3{\mu}Sv$ at 15MV. Conclusion : As a result, it is possible to reduce photoneutron dose using FFF mode and VMAT method with TrueBeam $ST{\time}TM$. The risk for secondary cancer of the patients will be decreased with continuous evaluation of the photoneutron dose.