• The Journal of the Korean dental association
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• v.43 no.12 s.439
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• pp.799-808
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• 2005

이 연구의 목적은 치수 및 치근단 조직의 감염의 주요 원인들이 Porphyromonas endodontalis의 LPS가 치주인대 섬유아세포의 MCP-1 MIP-1α 그리고 RANTES의 생성에 미치는 영향을 관찰함으로써 치근단 염중의 발병에서 섬유아세포의 역할을 알아보는 것이다. 혐기성 조건에서 배양한 P. endodontalis와 E. coil의 LPS를 추출, 정제한 후, 치주인대 섬유아세포 0.01, 0.1, 1, 10ug/ml 농도의 P. endodontalis와 E. coil의 LPS로 12, 24, 48시간 동안 자극하였다. MCP-1, MIP-1α 그리고 RANTES의 단백질 농도는 ELISA를 이용하여 분석하였다. 이연구의 결과는 아래와 같다. 1. P. endodontalis의 LPS로 자극시킨 치주인대 섬유아세포에서 분비된 MCP-1의 수준은 시간과 농도에 비례하여 증가하였다. 2.E.coil의 LPS로 자극시킨 치주인대 섬유아세포에서 분비된 MCP-1의 양도 시간에 비례하여 증가함을 보였다. 이는 P. endodontalis LPS보다 통계적으로 유의성있게 많은 양을 나타냈다.(p<0.05) 3. 치주인대 섬유아세포에서 MIP-1α 과 RANTES는 거의 분비되지 않았다. 이 연구에서 세균의 LPS로 자극시 치주인대 섬유아세포 MCP-1의 강한 발현은 만성 치근단 염증의 초기에 단핵세포와 대식세포의 recruitment를 증가시키는 것고 관련되어지는 것으로 보인다.

• Journal of the Korean Geosynthetics Society
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• v.6 no.1
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• pp.27-32
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• 2007

This paper describes the applicability of geogrid with I-type coupling system, which permits vertical displacement on back fill ground of the reinforced retaining wall and also minimize the damage between block and geogrid. The improvement of coupling method allowed the reduction of approximately 700 mm in the existing geogrid, and as a result, the tensile strength at the coupling joint showed approximately 53% of the maximum tensile strength. It is expected from the laboratory investigations that the coupling strength of geogrid with the combination of in-situ supporting material should be predominant in the field condition.

• Journal of the Korea Institute of Military Science and Technology
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• v.14 no.3
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• pp.335-344
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• 2011

In this paper, the results of computational analysis for the stability and F.S.(Factor of Safety) of Bailey Panel Bridge have been presented by FEM(Finite Element Method). The computational analysis was conducted by using LUSAS V14.0 that is a program applicated in the field of Civil Engineering. 6-free beam elements and 3-free truss elements were considered and F.S. against Yield Stress of main sections(considered self-weight and Live-Load) was investigated through the linear-elastic analysis method. The results showed that currently used sections of bailey bridge satisfied for the standard F.S. unit and could be operated in drill of troops and battle fields.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.57 no.12
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• pp.2186-2193
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• 2008

The growth on consideration of energy savings and motor efficiency has caused the LSPM(Line Start Permanent Magnet Motor) to be focused as a substitute for conventional induction motors. A Line start permanent magnet motor able to be driven at synchronous speed is designed based on a single phase induction motor in this paper. The single phase LSPM is identical to the induction motor except a permanent magnet is installed in the rotor. As the permanent magnet influences the characteristics of both transient state and steady state, a design considering both starting and synchronization conditions was used. In this paper, by adopting DOE, a single phase motor has been designed showing high power and smooth start. Also, optimal model is selected by weighting function. And the characteristics demagnetization are analyzed according to the variation of magnet shape. Finally, to verify the design results, a prototype was measured.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2009.11a
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• pp.81-85
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• 2009

In the recent years, the high strength concrete has increasingly been used according to extending market of tall buildings. However, Ministry of Land, transport and Maritime Affairs was established by law with an alternative plan after June 2008 because of the weakness of high strength concrete accompanied spalling phenomena in fire. The mix design of concrete has to properly meet standards which are the spalling resistance of concrete and limited temperature of steel reinforcement. The fire proof concrete mixed fiber has widely been used to meet spalling safety on the many construction sites, the most researches about the fire proof concrete mixed fiber had being carried out focused on fire resistance, compressive strength and cast in place of concrete. But the most important thing is column shortening used the fire proof concrete within the vertical members. In this paper, the fire proof concrete filled spalling safety standards was experimented by required material when the column shortening is revised between normal concrete and fire proof concrete mixed fiber and then the results have done a comparative analysis. Also, The paper aimed to indicate a basic data for revision of column shortening of fire proof concrete.

• Bulletin of the Korean Chemical Society
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• v.29 no.9
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• pp.1742-1746
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• 2008

Catechol and caffeine were simultaneously analyzed with a bismuth-immobilized carbon nanotube paste electrode (BPE) using square wave (SW) stripping voltammetry. Optimum analytical conditions were determined. Simultaneous working ranges of 100-1,500 $mgL^{-1}$ for caffeine and 5-75 $mgL^{-1}$ for catechol were obtained. In the separated cell systems, a working range of 0.1-2.1 $mgL^{-1}$ catechol with a correlation coefficient of 0.9935, and a working range of 10-210 $mgL^{-1}$ caffeine with a correlation coefficient of 0.9921 were obtained. A detection limit (S/N) of 0.15 $mgL^{-1}$ (7.7 ${\times}$ $10^{-7}$ M) and a detection limit of 0.02 $mgL^{-1}$ (1.82 ${\times}$ $10^{-7}$ M), respectively, manifested for catechol and caffeine. It was found that three macro-type electrode systems could be implanted in fish and rat neuro cells. For both ions, the ion currents were observed. The physiological impulse conditions and the neuronal thinking current were also obtained.

• ETRI Journal
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• v.28 no.3
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• pp.389-392
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• 2006

In this letter, a laterally-driven bistable electromagnetic microrelay is designed, fabricated, and tested. The proposed microrelay consists of a pair of arch-shaped leaf springs, a shuttle, and a contact bar made from silicon, low temperature oxide (LTO), and gold composite materials. Silicon-on-insulator wafers are used for electrical isolation and releasing of the moving microstructures. The high-aspect-ratio microstructures are fabricated using a deep reactive ion etching (DRIE) process. The tandem-typed leaf springs with a silicon/gold composite layer enhance the mechanical performances while reducing the electrical resistance. A permanent magnet is attached at the bottom of the silicon substrate, resulting in the generation of an external magnetic field in the direction vertical to the surface of the silicon substrate. The leaf springs show bistable characteristics. The resistance of the pair of leaf springs was $7.5\;{\Omega}$, and the contact resistance was $7.7\;{\Omega}$. The relay was operated at ${\pm}0.12\;V$.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.28 no.4
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• pp.427-434
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• 2004

Ferritic stainless steel is recently used in high temperature structures because of its good properties of thermal fatigue resistance, corrosion resistance, and low price. Tensile and low-cycle fatigue (LCF) tests on 429EM stainless steel used in exhaust manifold were performed at several temperatures from room temperature to 80$0^{\circ}C$. Elastic Modulus, yield strength, and ultimate tensile strength monotonically decreased when temperature increased. Cyclic hardening occurred considerably during the most part of the fatigue life. Dynamic strain aging was observed in 200~50$0^{\circ}C$, which affects the cyclic hardening behavior. Among the fatigue parameters such as plastic strain amplitude, stress amplitude, and plastic strain energy density (PSED), PSED was a proper fatigue parameter since it maintained at a constant value during LCF deformation even though cyclic hardening occurs considerably. A phenomenological life prediction model using PSED was proposed considering the influence of temperature on fatigue life.

• Journal of the Society of Naval Architects of Korea
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• v.44 no.4
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• pp.360-369
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• 2007

When a large ship is advancing in waves, ship undergoes the hydroelastic response, and this have influence on structural stability and the fatigue destruction etc. of ship. The main objective of this research is to develop an accurate and convenient method on the hydroelastic response analysis of ships on the real sea states. We analyzed hydroelastic responses, which is formulated by finite element method. The numerical approach for the hydroelastic responses is based on the combination of the three dimensional source distribution method, the dynamic response analysis and the spectral analysis method. The calculated results show good agreement with the experimental and calculated ones by Watanabe.

• International Journal of Industrial Entomology and Biomaterials
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• v.7 no.2
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• pp.161-164
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• 2003

Several polyhydroxylated alkaloids were isolated from the extracts of freeze-dried silkworm powder, and purified by ion exchange chromatographic analysis. Through the HPLC analysis, we could identify 1-deoxynojirimycin (DNJ) and a kind of calystegin $B_2$ (HS-58) as well as a noble compound (HS-74) from the purified polyhydroxylated alkaloids. In order to know the characteristics of these isolated alkaloids as enzyme inhibitors, glycosidase inhibition activities of these identified alkaloids including other two non-purified alkaloids (SWP 3-1 and SWP 3-2) were investigated.