• Tunnel and Underground Space
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• v.15 no.6 s.59
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• pp.432-440
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• 2005

Baehuryeong tunnel connects Chuncheon with Hwacheon in Kangwon, Korea, This tunnel is a single tunnel with 5,057 m long and two bidirectional lanes which will be extended into low lanes in the future. The estimated construction period of Baehuryeong tunnel is approximately 55 months. This tunnel will become the longest bidirectional roadway tunnel in Korea. Compared to a twin tunnel, a bidirectional single tunnel has two major disadvantages with regard to the ventilation system and ease of escape during fire. For these reasons, a service tunnel and the transverse ventilation system are planned first time in Korea. In case of fire, the tunnel ventilation design aims to maintain a smoke free layer for passenger evacuation. The geology of Baehuryeong tunnel site is mainly composed of gneiss and granite. Baehuryeong fault is a mainly large scale fault which stands vertical and parallels with tunnel direction. The influenced zone of this fault is within 70 m. Baehuryeong tunnel was designed that it was separated with the distance of more than 100 m from Baehuryeong fault for its safety.

• Journal of Mushroom
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• v.20 no.3
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• pp.168-172
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• 2022

This study was conducted to investigate the optimum supplementation ratio when replacing cotton seed meal with rapeseed meal for cultivating oyster mushrooms. The chemical properties among the treatments were pH 4.5~4.7, total carbon content was 46.3~46.5%, total nitrogen content was 1.6~1.7%, and carbon-nitrogen ratio was 27.0~27.8. These did not differ significantly from the control. Mycelial growth was 85.1 mm (Heuktari), and 72.8 mm (Suhan-1Ho) in medium containing 5% rapeseed meal, with no significant difference in mycelial density between cultivars. Fruiting body characteristics are as follows: In 'Heuktari', the color of the pileus was darker than control with an L value of 32.5, and pileus thickness and diameter were 3.2 mm and 27.6 mm, respectively. Stipe length and diameter were 86.0 mm and 9.1 mm, respectively. Valid stipe number per bottle (1,100 cc) was 25.9, and a yield of 189.7 g/1,100 cc was recorded in mixed medium containing 5% rapeseed meal (higher than control). In mixed medium containing 10% rapeseed meal, the yield was 184.5 g/1,100 cc (comparable to control). In 'Suhan-1Ho', supplemented with 5% rapeseed meal, pileus color was darker than control color, with an L value of 28.8. Pileus thickness was 4.5 mm. Stipe diameter was 12.3 mm (higher than control), and yield was 145.5 g/1,100 cc (comparable to control).

• Journal of Dental Rehabilitation and Applied Science
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• v.25 no.4
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• pp.417-429
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• 2009

Since the introduction of the concept of osseointegration in dental implants, high long-term success rates have been achieved and accepted as viable option for the treatment of fully and partially edentulous patients. Although the use of domestic implants have increased dramatically, there are few studies on domestic implants with clinical and objective long-term data. 96 endosseous implants placed in 31 patients at Wonkwang University Sanbon Dental Hospital were examined to determine the effect of various factors on implant survival rate and marginal bone loss, through clinical and radiographic results. The design of endosseous implant used to this study is straight with the microthread.(GS II RBM Fixture) 1. 3 fixtures were lost, resulting in 96.9% cumulative survival rate. 2. Survival rate in fifties was significantly lower (93.6%) and no significant difference in marginal bone loss was found according to gender. 3. Survival rates were 95.6% in the maxillary molar area and 97.3% in the mandible molar area. 4. No significant difference in survival rate was found according to presence of bone grafts, type of prostheses, implant position, and length and diameter of implant. 5. A factor influencing marginal bone loss was presence of type of prostheses, while facters such a length, diameter of fixture and bone grafts had no statistically significant effect on crestal bone loss. This study indicates the amount of marginal bone loss around implant has maintained a relative stable during follow-up periods.

• Composites Research
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• v.22 no.6
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• pp.1-6
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• 2009

This paper presents an experimental study on the piezoresistive behavior of nanocomposite strain sensors subjected to various loading modes and their capability to detect structural deformations and damages. The electrically conductive nanocomposites were fabricated in the form of a film using various types of thermoplastic polymers and multi-walled carbon nanotubes (MWNTs) at various loadings. In this study, the nanocomposite strain sensors were bonded to a substrate and subjected to tension, flexure, or compression. In tension and flexure, the resistivity change showed dependence on measurement direction, indicating that the sensors can be used for multi-directional strain sensing. In addition, the sensors exhibited a decreasing behavior in resistivity as the compressive load was applied, suggesting that they can be used for pressure sensing. This study demonstrates that the nanocomposite strain sensors can provide a pathway to affordable, effective, and versatile structural health monitoring.

• Journal of the Korean Society of Propulsion Engineers
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• v.15 no.4
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• pp.48-56
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• 2011

A Possibility of combustion instability on longitudinal mode has a high level at large scale of L/D. Solid propellant has a metal particle and a grain of control to pressure oscillation. Solid rocket motor in slotted-tube grain controls pressure oscillation of longitudinal mode. Slotted-tube grain restrains longitudinal 1st pressure oscillation. But cavity volume of aft. insulation ablation amplifies 2nd pressure o scillation by vortext shedding. A study has suppressed combustion instability and vortex shedding by modified 4 slotted tube solid rocket motor design.

• Composites Research
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• v.26 no.3
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• pp.147-154
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• 2013

Nanocarbons such as carbon nanotubes (CNT) and graphene are considered to be ideal fillers for polymer composites, because of their outstanding mechanical properties and high length-to-diameter ratio. There has been much effort to realize the implementation of their full potential, but a large number of unsolved problems still must be challenged, for example, effective processing for fabrication. This review deals with the progress that has already been made in the area of nanocarbon polymer composites using CNT and graphene. Mechanical reinforcement of various nanocarbon polymer composites is analyzed and compared, and future perspectives in research and development that need to be done are discussed.

• The Korean Journal of Mycology
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• v.36 no.1
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• pp.58-62
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• 2008

'Miso', a new variety of oyster mushroom was developed for the bottle culture at the Chungnam Agricultural Research & Extension Services. Its mycelium grew rapidly with $8.4{\sim}8.6\;mm/day $ at $25{\sim}28^{\circ}C$ on PDA medium. The optimum pH of the mycelial growth was pH 5.0. It took 24 days for the primitive primordium formation after inoculation on pine sawdust media mixed with 20% wheat bran. Fruiting body color was white, and the shape of pileus was convex-umbonate. In the bottle culture, the yield was 115.7 g per 850 ml bottle. Stipe length was about 54 mm, the number of stipe per bottle was 18.1, the size of pileus was 28 mm, and gill was crowded. The moisture content of 'Miso' was lower than that of Jangan No.5 and Wonhyeong No.1, and contents of protein, ash and sugar of 'Miso' were higher than those of other varieties, and tannin acid content of 'Miso' was lower than that of others. On the basis of AFLP analysis, the 'Miso' was distinct not only from Wonhyeong No.1, but also from their closest relative, oyster mushrooms.

• Journal of the Korean Geotechnical Society
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• v.30 no.1
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• pp.103-116
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• 2014

This paper presents the results of a numerical investigation on the load carrying capacity and consolidation behavior of suction piles. Three dimensional numerical models which reflect realistic ground conditions and installation procedures including the ground-suction pile interface were adopted to conduct a parametric study on variables such as the length-diameter ratio and the loading configurations, i.e, vertical, horizontal, and combined loads. The results indicated that the load carrying capacity of a suction pile can only be realistically obtained when the interface behavior between the suction pile and the ground is correctly modeled. Also carried out was the stress-pore pressure coupled analysis to investigate the consolidation behavior of the suction pile after the application of a vertical loading. Based on the results, failure envelops and associated equations were developed, which can be used to estimate load carrying capacity of suction piles installed in similar conditions considered in this study. The results of consolidation analysis based on the stress-pore pressure coupled analysis indicate that no significant excess pore pressure and associated consolidation settlement occur for the loading configuration considered in part due to the load transfer mechanism of the suction pile.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.20 no.7
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• pp.617-624
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• 2009

In this paper, an electromagnetic analysis methodology using reaction theorem based on reciprocity theorem is presented for the aspheric ogival radome applied to a missile and/or airborne radar. The presented analysis methodology is verified using actual measured data. The type of antenna assumed to develope the methodology is a waveguide slot array antenna, and has the structure of 2 axes monopulse of "X" type. The shape of radome is assumed as Von Karman and the ratio of length to base diameter(L/D) is assumed to be 2:1. The electrical characteristics of the radome are measured using radome measurement system and the results are compared to the values estimated using the presented analysis methodology. It is found that the comparison shows good agreement. It is expected that the presented methodology can be applied for the development of missile and airborne radome.

• Journal of the Korean Society of Propulsion Engineers
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• v.21 no.2
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• pp.111-118
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• 2017

In this paper, combustion tests were performed to investigate performance characteristics of a canted slit-type pintle injector engine which uses kerosene and liquid oxygen as propellants. The number of slits, slit angle and blockage factor were chosen as design variables of the pintle injector. ${\Delta}SR$ was newly defined as the difference of skip ratio caused by both sides of the tip of the canted slit. The experimental results showed that optimal combustion was performed when the blockage factor is about 1 and the difference is less than 0.26.