• Journal of Korea Water Resources Association
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• v.39 no.6 s.167
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• pp.479-486
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• 2006

In this study, 2-D seepage analysis is conducted for the evaluation of Box-Culvert installation, Cut-off Wall Length, permeability reduction of soil under the Box-Culvert effects on Levee Box-Culvert safety. The result of analysis it is obtained that the safety of seepage and slope stability of levee is declined by the installation of Box-Culver. And also obtained that the piping from poor compaction and cavity around Box-Culvert Is Prevented by the Cut-off wall installation below breast wall and levee toe, so it is recommended that the Cut-off Wall below breast wall and levee toe must be installed. And the Cut-off Wall installed below levee center is considered when the safety of piping is declined for the whole levee section. On the other hand, for the realistic analysis it is recommended that the 3-D seepage analysis is more suitable for the safety evaluation of Box-Culvert installed levee when it is considered that the saturated field is dispersed to the ground.

• Journal of Korean Society of Forest Science
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• v.102 no.2
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• pp.229-238
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• 2013

This study was conducted to analyze on the operational cost of logging operations in the whole-tree logging operation system by tower-yarder and swing-yarder, and in the cut-to-length logging operation system by excavator with grapple in order to spread efficient logging operation technique and to establish the logging operation system. In the results of the analysis of operation cost, in case of the whole-tree logging operation system, the operation cost was 2,099 won/$m^3$ in felling by chain saw, 28,286 won/$m^3$ in yarding by tower-yarder, 18,265 won/$m^3$ in yarding by swing-yarder, 18,939 won/$m^3$ in bucking by excavator with grapple and chain saw, 20,484 won/$m^3$ in forwarding and accumulation by wheel type mini-forwarder, 12,701 won/$m^3$ in forwarding and accumulation by excavator with grapple and small forwarding vehicle. In case of the cut-to-length logging operation system, the operation cost was 10,160 won/$m^3$ in felling and bucking by chain saw, 7,567 won/$m^3$ in cut-to-length extraction by excavator with grapple, 6,982 won/$m^3$ in branches and leaves extraction by excavator with grapple, 3,040 won/$m^3$ in the operation road construction by excavator with grapple, 20,484 won/$m^3$ in forwarding and accumulation by wheel type mini-forwarder, 12,701 won/$m^3$ in forwarding and accumulation by excavator with grapple and small forwarding vehicle.

• Food Science and Preservation
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• v.24 no.6
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• pp.827-833
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• 2017

This study was investigated the effects of various commercial sanitizers on microbial characteristics in fresh-cut iceberg lettuce during storage. For screening sanitizer, lettuce was cut and dipped in chlorine water ($0.2ml{\cdot}L^{-1}$), solution of organic acids such as ascorbic acid, citric acid, acetic acid, mixture of ascorbic acid and acetic acid (1-6%), and solutions of commercial sanitizers such as Formula 4$^{TM}$ (1,3,4%), Fresh produce wash$^{TM}$ (1,3,4%), Cleancol$^{TM}$ (1%), Chitochol$^{TM}$ (1%) and Natural Ca$^{TM}$ (0.1%) for 3 min, respectively. Washing lettuce with selected sanitizers resulted in reduction of aerobic bacteria of more than 2 log CFU/g. Initial pH of lettuce was related with the pH of sanitizers. pH ranged from 4.7 to 6.1 in Formula 4 (4%, pH 1.7) and Natural Ca (0.1%, pH 12.0), respectively. Chlorine water showed consistent and significant inhibition effect in all of microorganisms except total coliform. Over 3% of Formula 4 and Fresh produce wash were found to have high bactericidal activity among sanitizers. The sanitizers of chlorine water, Fresh produce wash, Chitochol and Natural Ca were effective in reducing yeast and mould populations. As coliform and E. coli, Formula 4 (4%) showed the highest bactericidal activity. The bactericidal effect of commercial sanitizers during storage varied with the kinds and concentrations of tested sanitizers. Although inhibition effect was not showed during storage, these results suggest that commercial sanitizers could be an alternative to chlorine for washing fresh-cut produce.

• Tunnel and Underground Space
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• v.28 no.6
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• pp.692-705
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• 2018

Ground vibration is one of the remarkable issues in tunnel blasting. In recent studies, to improve the fragmentation with reduction of ground vibration in tunnel blasting, a vibration-controlled blasting method with artificial cutting slot near the center-cut holes has been suggested. This study examines the effect of the different arrangement of artificial cut-slot on the vibration reduction and fragmentation by performing the full-scaled concrete block blast experiments and the numerical simulations with 3D-DFPA. The results show that the existence of artificial slot contributes to the improvement of vibration reduction, blast fragmentation and the efficiency of the cutting slot blast. It can be explained that the artificial slot play a free surface role and should decrease the burden between the cut holes. Crater volumes of the blasted concrete blocks were measured by 3-dimensional digital image analysis and compared with the ideal standard crater volume which can be calculated by theoretical standard blast design method. As a result, the ratio of burden and hole diameter which should achieve the standard crater in the cut-hole blasting were suggested.

• Proceedings of the KSR Conference
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• 2011.05a
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• pp.456-461
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• 2011

Recently the design specification has been advanced with preventing earthquake disaster in Korea because of increasing occurrence of large size earthquake. A composite plate with ductile fiber is proposed, which can enhance the performance of built tunnel in both strength and ductility. This study is to focus to verify the effect of strengthening of existing tunnels which is built without earthquake type load scenario, so that it can provide the safety of existing urban subway system against earthquakes.

• Proceedings of the Optical Society of Korea Conference
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• 1990.02a
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• pp.219-221
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• 1990

Y-branch directional coupler type optical modulators with three different coupling lengths were fabricated on z-cut LiNbO3 and tested at λ-1.3${\mu}{\textrm}{m}$. One device gad an exact coupling length for complete power transfer and two other devices had coupling lengths. It was confirmed that, for dc operation, experimental results agreed well with theoretical results.

• Proceedings of the Korean Society of Machine Tool Engineers Conference
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• 1998.03a
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• pp.184-189
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• 1998

In the CNC lathe working, the study of the effects of various cutting conditions on cut surface roughness is less active than that of the ordinary latee. After lathe working of SM45C, a carbon steel material for machine structure, its surface roughness was measured using a stylus surface roughness tester. In most cases, good surface roughness was obtained over 160m/min cutting speed and then the proper cutting depth was found as 1.0~1.5mm.

• Journal of Welding and Joining
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• v.11 no.1
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• pp.33-41
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• 1993

TIME 용접법용 혼합 가스의 특성으로 인하여 기존의 GMAW 용접법과 비교하여 TIME 용접법 은 다음과 같은 장점이 있다. 1.용적 이행이 아크 플라즈마 기둥 내부에서만 일어난다. 2.용입이 깊고, 비드 단면현상도 뛰어나다. 3.용착량을 최대 450g/min까지 증가 시킬수 있다. 4.용접속도의 향상, pass수 감소, 결함발생이 적다. 5.저온 충격시험치를 향상시킨다. 6.비드외관이 미려하고, under cut 및 lack of fusion등의 결함발생 위험이 적다. 7.스패터 발생이 극히 적다. 8.자동 및 반자동 용접이 가능하다. 9.전체적인 용접비용이 대폭 절감된다.

• Proceedings of the PSK Conference
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• 2003.04a
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• pp.269.2-269.2
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• 2003

An extract of Alnus japonica (Betulaceae) cortex has been traditionally used for purifying blood, and curing feces containing blood, enteritis, diarrhea, alcoholism and cut wounds. In the preliminary test was carried out for determining whether it has the novel pharmacological activity, the butanol fraction showed significant inhibitory effect on carrageenan-induced paw edema as an acute inflammation, HCI.ethanol-induced gastric lesion and aspirin-ligation gastric ulcer. (omitted)

• Journal of the Chungcheong Mathematical Society
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• v.36 no.2
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• pp.125-133
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• 2023

We establish a characterization theorem of elliptic paraboloids in the (n+1)-dimensional Euclidean space 𝔼ⁿ⁺¹ with extrinsic properties such as the (n+1)-dimensional volumes of regions enclosed by the hyperplanes and hypersurfaces, and the n-dimensional areas of projections of the sections of hypersurfaces cut off by hyperplanes.