• Transactions of the Korean hydrogen and new energy society
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• 제23권4호
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• pp.412-419
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• 2012

Increasing demand for natural gas and higher natural gas prices in the recent decades have led many people to pursue unconventional methods of natural gas production. POSCO-Gwangyang synthetic natural gas (SNG) project was launched in 2010. As the market price of natural gas goes up, the increase of its price gets more sensitive due to the high cost of transportation and liquefaction. This project can make the SNG economically viable. In parallel with this project, KEPCO (Korea Electric Power Corporation) joined in launching the SNG Quality Standard Bureau along with KOGAS (Korea Gas Corporation), POSCO and so on. KEPCO Research Institute is in charge of SNG fueled gas turbine combustion test. In this research, several combustion tests were conducted to find out the effect of hydrogen contents in SNG on gas turbine combustion. The hydrogen in synthetic natural gas did not affect on gas turbine combustion characteristics which are turbine inlet temperature including pattern factor and emission performance. However, flame stable region in ${\Phi}$-Air flow rate map was shifted to the lean condition due to autocatalytic effect of hydrogen.

• The Journal of the Convergence on Culture Technology
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• 제6권1호
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• pp.361-366
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• 2020

The Korean movies, and are suitable for "B-movie" for spending low budget and utilizing subculture factors such as kitsch, parody. Using surrealistic space and arbitrary language is the most prior element in constituting 'B-affection'. In that sense, Behind the Dark Night, Super Margin have characteristics overcrossing the media from comics to film. Despite absurd story, Behind the Dark Night has a realistic and concrete sense of what is the making films. The hero in Super Margin was swindled, so he strikes a blow the breeding-place of crime himself. In conclusion, showing comics characteristic aspects has been increasing comedy effects. But, on the other hand, Behind the Dark Night, Super Margin have pointed out that there are many kind of social problems such like career, fraud etc. In addition, they introspect the meaning what is that to making films.

• Korean Journal of Agricultural Science
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• 제10권1호
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• pp.156-165
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• 1983

This experiment was carried out to elucidate the drying characteristics of onion and dehumidifying effect of air using the silica gel and to reuse it by solar collector. The results were summarized as follows. 1. It takes 14hours to regenerate to silica gel of 8% moisture content from saturated silica gel in conditions of $28^{\circ}c$ temperature and 55% relative humidity. 2. When sample was recycled through solar collector, the result of drying was 1/2 times more efficient than that of mat drying. 3. Average thermal efficiency of solar collector was 25% during the experimental period. 4. Browning extent was reduced to 1/2 times at heated air blow drying system using drying chamber.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• 제15권10호
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• pp.969-976
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• 2004

The wide and growing use of cellular phones has raised the question about the possible health risks associated with radio-frequency electromagnetic fields. It would be helpful for phone users to blow the exposure levels during cellular phone use. But it is very difficult to recognize the amount of exposure, because measuring accurate level of RF is a difficult matter. In this study, we developed a model to estimate the exposure level and the individual risk of exposure by utilizing the available informations that we can get. We used such parameters as usage time a day, total using period, distance between cellular phone and head, slope of cellular phone, hands-free usage, antenna pulled out or not SAR(Specific Absorption Rate) of cellular phone, and flip or folder type. We proposed a model presenting individual risk of RF exposure from level 0 to 10 by using a neural network.

• Archives of Craniofacial Surgery
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• 제18권4호
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• pp.249-254
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• 2017

Background: Lower eyelid incisions are widely used for the orbital approach in periorbital trauma and aesthetic surgery. In general, the subciliary approach is known to cause disposition of the lower eyelid by scarring the anterior lamella in some cases. On the other hand, many surgeons believe that a transconjunctival approach usually does not result in such complications and is a reliable method. We measured positional changes in the lower eyelid in blowout fracture repair since entropion is one of the most serious complications of the transconjunctival orbital approach. Methods: To measure the positional changes in the lower eyelids, we analyzed preoperative and postoperative photographs over various time intervals. In the analysis of the photographs, marginal reflex distance 2 ($MRD_2$) and eyelash angle were used as an index of eyelid position. Statistical analyses were performed to identify the significance in the positional changes. All patients underwent orbital reconstruction through a transconjunctival incision by a single plastic surgeon. Results: In 42 blowout fracture patients, there was no statistical significant difference in the MRD2 and eyelash angle. Furthermore, there were no clinical complications, such as infection, hematoma, bleeding, or implant protrusion, during the follow-up periods. Conclusion: The advantages of the transconjunctival approach for orbital access include minimal scarring and a lower risk of eyelid displacement compared with other approaches. Based on these results, we recommend the transconjunctival approach for orbital exposure as a safe and reliable method.

• Journal of Biosystems Engineering
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• 제34권2호
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• pp.106-113
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• 2009

This study was carried out to test feasibility of a granule fertilizer applicator for rapeseed seeding in paddy fields. The metering plate of a conventional applicator was modified for rapeseed seeding. The modified plate had new three seeding openings with total area of $342mm^2$. Average target discharging rates ranged from 6.3 to 21.0 g/s and correlated with opening areas. Application patterns of the rapeseed seeding showed M-shape. The coefficients of variation of the application showed 70.5% at 0.99 m/s of forwarding speed and 14.3 g/s of a discharge rate, and 77.7% at 1.72 m/s of a forwarding speed and 8.23 g/s of a discharge rate. The coefficients of variation in the direction of transverse of the tractor ranged from 7.3 to 47.7%. In rapeseed seeding tests using the applicator, seed damages rates were less than 15% due to the agitator, the seed hopper and the seeding plate break. Therefore, improvements of the applicator blow heads and seeding equipments were required in order to apply rapeseed efficiently.

• Archives of Craniofacial Surgery
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• 제14권1호
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• pp.30-35
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• 2013

Background: For reconstruction of the mild to moderate medial orbital wall fractures, various surgical approaches have been used. Prior existing W-shaped incision was a direct local approach through a 3 cm incision on the superior medial orbital area with a titanium mesh implant. In this study, the authors modified W-shaped incision and reconstructed the defect with silastic sheet to improve the result and the postoperative scar. Methods: This study included 20 patients who had mild to moderate size of medial wall defect and therefore relatively suitable for reconstruction with silastic sheets from July, 2009 to December, 2011. A modified W-shaped skin incision approximately 1.2 to 1.5 cm in length was made along the superior medial orbital rim from approximately 1 cm medial to the medial canthus to the lower border of the medial eyebrow. The angles of the limbs of the W ranged from 150 to 160 degrees. Results: By using soft flexible silastic sheet, the authors reduced the incision from 3 to 1.5 cm, and by widening the angle of the W limbs, scars were more effectively hided in the relaxed skin tension line. Scar assessment was done with modified patient and observer scar assessment scale and mean score from patients was 2.08 and mean score from observers was 2.12. Conclusion: Although this method will not be suitable for every case, it can be a consistent method to obtain the surgical goal in treatment of mild to moderate blowout fractures of the medial orbital wall.

• Journal of the Korean Society of Propulsion Engineers
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• 제4권4호
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• pp.78-86
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• 2000

The objective of this research is to understand the characteristics of a nonpremixed, turbulent, hydrogen jet flame which is stabilized in Mach 1.8 coflowing air flows. In order to investigate the flame structure, flame lengths and fuel trajectories were measured by using direct photography, acetone PLIF, Mie scattering techniques, and numerical simulation. Effect of increasing air velocity was investigated when fuel velocity is fixed. The subsonic flame length was decreased drastically, however the supersonic flame length was increased slowly Then the change of flame blow out characteristics was observed as varying fuel nozzle lip thickness. The flame stability can be increased when fuel nozzle lip thickness was increased, which indicates that the minimum fuel lip thickness ratio is required for the stable supersonic flames. Also, it is found that fuel jet is blocked by high pressure zone and low scattering zone is made. Then the fuel that was moving along the recirculation zone had longer residence time within the supersonic flames, which made partially premixed zone.

• Journal of Clinical Otolaryngology Head and Neck Surgery
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• 제29권2호
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• pp.198-203
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• 2018

Background and Objectives : Pediatric orbital blowout fractures occur in discreet patterns, in reference to the characteristic developmental anatomy of the facial skeleton at the time of injury. The purpose of this study was to investigate the clinical characteristics, ocular symptom, fracture type and postoperative results of orbital blowout fractures in the pediatric population. Material and Methods : A retrospective study was conducted from January 2009 to June 2015 in 116 patients with orbital floor fractures ; all less than 18 years old. Patients were divided into 3 groups by age : 0 to 6, 7 to 12, and 13 to 18 years of age. The cause of fracture, fracture site and type, preoperative and postoperative ocular symptoms, timing of surgery were reviewed from their records. Results : Medial wall fractures were the most common site in the 0 to 6 years old group, and floor fractures were the most common site in other age groups. However, floor fracture was the most common site of the need for surgery in all age groups. Trapdoor type of fractures occurred more frequently than open door type of fractures in all age groups. Preoperative symptoms did not differ among the 3 age groups. In case of need surgery, frequency of preoperative ocular symptoms increased with age. However, as age group was young, rate of residual postoperative ocular symptoms were increased. Conclusions : The younger patients are more to have trapdoor type fracture and residual postoperative ocular symptom. Earlier surgical intervention more needed for children with entrapment results.

• Archives of Craniofacial Surgery
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• 제20권4호
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• pp.223-227
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• 2019

Background: Neurosensory changes are frequently observed in the patients with mid-face fractures, and these symptoms are often caused by infraorbital nerve (ION) damage. Although ION damage is a relatively common phenomenon, there are no established and objective methods to evaluate it. The aim of this study was to test whether trigeminal somatosensory evoked potential (TSEP) could be used as a prognostic predictor of ION damage and TSEP testing was an objective method to evaluate ION injury. Methods: In this prospective TSEP study, 48 patients with unilateral mid-face fracture (only unilateral blow out fracture and unilateral zygomaticomaxillary fracture were included) and potential ION damages were enrolled. Both sides of the face were examined with TSEP and the non-traumatized side of the face was used as control. We calculated the latency difference between the affected and the unaffected sides. Results: Twenty-four patients recovered within 3 months, and 21 patients took more than 3 months to recover. The average latency difference between the affected side and unaffected side was 1.4 and 4.1 ms for the group that recovered within 3 months and the group that recovered after 3 months, respectively. Conclusion: Patients who suffered ION damage showed prolonged latency when examined using the TSEP test. TSEP is an effective tool for evaluation of nerve injury and predicting the recovery of patients with ION damage.