• Journal of the korean academy of Pediatric Dentistry
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• v.26 no.2
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• pp.416-426
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• 1999

The objective of this study is to confirm the effect of dentine bonding primer application on penetration of sealant. Extracted permanent molars were used to compare penetration success rate of control group (sealant application only) and experimental groups (sealant application after applying the primers of $Scotchbond^{TM}$ Multi-Purpose system and $All-Bond^{(R)}$ 2 system). The following results were obtained: 1. The experimental groups using the primers showed increased sealant penetration success rate to the base of fissure when compared to control group but there was no statistically significant differences(p>0.05). 2. The depth, width and 'depth/width' value of fissure had statistically significant effect on sealant penetration success rate(p<0.05). 3. The penetration success rate decreased about 0.9 times as the depth of fissure increased every $25{\mu}m$, and increased about 1.1 times as the width of the fissure orifice increased every $25{\mu}m$ and decreased about 0.6 times as the 'depth/width' value increased every 1. From the above results, it can be concluded that assure morphology had a great effect on sealant penetration and for better penetration, use of dentine bonding primer can be helpful but it needs more study in clinical bases.

• Journal of the Korea Institute of Building Construction
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• v.11 no.3
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• pp.256-264
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• 2011

By implementing an analysis on the liquid flame proof agent infiltration of microwave-heated wood under soaking conditions (room temperature soaking, heat soaking), its correlation with wood temperature, and the structure of wood and permeating components after soaking in flame proof agent, which was carried out as basic research in order to improve the fire resistance performance of the wood itself, it is found that the infiltration increases as the microwave heating time increases, while for heat soaking, it is found that high infiltration as well as the stable permeability of flame proof agent is achievable. Also, when the wood temperature is more than $80^{\circ}C$, the infiltration by the flame proof agent increased, and a very even infiltration of flame proof agent was observed, which implies that the liquid flame proof agent has a dependency on temperature change of the wood as a condition to penetrate into the wood. As a result of fine structure analysis, the flame proof agent transfer between cells through pits was considered as a cause to increase the infiltration of flame proof agent, and it is also shown that for heat soaking among the permeating component analysis, as the crystallized flame proof agent around the heartwood and sapwood inner pits increases, the flame proof agent can penetrate into the the heartwood part.

• Journal of the Korean GEO-environmental Society
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• v.8 no.5
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• pp.47-55
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• 2007

The increment of impermeable land area due to widespread land development caused the adverse impact on urban disaster prevention because it could decrease the peak rate of runoff as well as increase the runoff and peak flow during rainy period. To date, little research has been conducted on the infiltration characteristics and quantitative analysis because of their highly dependence on construction method, paving material, surface permeability, and field condition. Hence, this study was performed to investigate the infiltration characteristics of runoff-reducing facilities according to the type of paving material, which were examined using experimental apparatus with varying paving material and rainfall intensity, and thus to provide fundamental research data for runoff-reducing infiltration facilities. In this study, the infiltration characteristics were examined under the rainfall intensity of 20, 30, 50, 80, 100, 200 mm/hr for a variety type of paving materials such as concrete, asphalt, sand, grassland, and permeable paving material. The infiltration rate for permeable paving material was observed to be more than 93% under the condition of less than 200 mm/hr of rainfall intensity. For the compacted earth and grassland, the ultimate infiltration rate was estimated to be about 13% to 67%. The permeable paving material was concluded to be the most appropriate one for the runoff-reducing infiltration facilities because it has more favorable advantages than others in the light of infiltration volume, disaster prevention, and river training.

• Journal of the Korea Concrete Institute
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• v.20 no.4
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• pp.469-475
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• 2008

It is obvious that chloride penetration through cracks can threaten the durability of concrete substantially, according to the previous studies of author. It was proposed that crack depth corrseponded with critical crack width from the surface is a crucial factor in view of durability design of concrete structures. It is now necessary to deal with chloride penetration through microcracks characterized with the mixing features of concrete. The purpose of this study is examining the effect of mix proportional features of concrete such as coarse aggregate, high strengtherize of concrete and reinforcement of steel fiber on chloride penetration through cracks. Although small size of coarse aggregate can lead to many microcracks in concrete, the cracks should not impact on chloride penetration directly. On the contrary, chloride should penetrate through cracks easily in concrete with a large size of coarse aggregate because mixrocracks are connected to each other. Second, high strength concrete has an excellent performance to resist with chloride penetration. However, for cracked high strength concrete, its performance is reduced upto the level of ordinary concrete. Finally, steel fiber reinforcement is effective to reduce chloride penetration through cracks because steel fiber reinforcement can lead to reduce crack depth significantly.

• Proceedings of the Korea Water Resources Association Conference
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• 2016.05a
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• pp.171-171
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• 2016

최근 도시화가 진행되면서 지표의 불투수화가 급격하게 진행되고 강우의 지표면 유출량이 급격하게 증가하여, 강수 시 첨두유출 시간이 감소하고 단기간 집중유출이 증대되어 폭우로 인한 도시 홍수등이 발생하고 있다. 이러한 현상에 효과적으로 적응하기 위해 환경적으로 지속가능한 도시 개발을 위한 그린인프라(GI, Green Infrastructure) 및 저영향개발기법(LID, Low Impact Developpment)이 국내에 도입되고 있다. 하지만 아직까지 투수성 포장의 물순환 성능 평가 및 설계 방법에 대한 기준이 명확하지 않으며, 많은 경우 투수성 포장의 적용은 유출저감효과에 대한 정량적 해석 없이 적용되고 있는 실정이다. 이에 본 연구에서는 경남 양산시 부산대학교 제 2 캠퍼스에 있는 "한국형 GI&LID 실증실험단지"에 투수 도로형 실증실험시설을 구축하였다. 실험 시설은 불투수 아스팔트와 투수 아스팔트, 불투수 콘크리트와 투수 콘크리트 비교실험 할 수 있으며 도로표면 유출수 및 침투수에 대한 유량 및 수질 측정 모니터링을 통해 침투효과 및 특성을 분석할 수 있으며 차후 투수성 포장의 클로깅 현상으로 인한 투수성능의 감소 등 여러 가지 실험을 할 수 있을 것이다.

• Proceedings of the Korea Water Resources Association Conference
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• 2004.05b
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• pp.1340-1344
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• 2004

우리나라는 계절에 따라 수량의 변화가 커서 하천에 흐르는 유량의 변화가 심하지만 대부분의 하천은 갈수기에도 각각 일정량의 유량을 가지고 흘러간다. 그러나 충적층을 통과하는 소하천의 경우에는 계절에 상관없이 하천수가 지하로 침투하여 지표수가 감소한다. 소하천의 하천수량이 갈소되거나 건천화 될 경우 수질이 악화되거나 하천의 바닥이 드러날 경우 수중생태계는 파괴됨 것이다. 현재 지하수를 개발하여 부족한 하천수를 보충하는 방법을 모색하고 있으나 하천수의 지하침투가 심각한 경우에는 지하수만으로는 하천수의 부족분을 보충하는데 한계가 있다. 충적층을 통과하는 소하천의 침투수를 차단하는 방법으로 충적층에 불투수 매트를 설치하여 사용하면 하천의 건천화를 방지할 수 있으며, 충적층의 침투수를 차단하기 위하여 충적층위에 점토층을 설치하여 투수계수를 저하시키는 방법을 사용하면 부족한 하천유지용수를 확보할 수 있다. 따라서 충적층을 통과하는 소하천의 건천화를 방지하고 자연형 하천으로 개발할 경우 수중생태계 복원성이 우수하며, 자연경관의 복원에도 효과가 있다.

• Agrochemical news magazine
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• v.22 no.9 s.172
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• pp.18-21
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• 2001

• Journal of the Korea Concrete Institute
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• v.19 no.6
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• pp.707-715
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• 2007

The vulnerability of concrete to its environment is significantly dependent on the fact that concrete is a porous material. For well-consolidated and well-cured concrete, its service life is a very long and an entrance of aggressive substance might be only pores. However, for cracked concrete, cracks should be preferential channel for the penetration of aggressive substance such as chloride ions. The effect of crack on chloride penetration depends on its size for example, crack width and crack depth. The purpose of this study is examining the effect of crack width and crack depth on chloride penetration. In order to visualize chloride penetration via cracks, RCM (rapid chloride migration) testing is accomplished. Crack width is examined using an optical microscope and CMOD value is used to estimate average crack width. From the examination on the trend of chloride diffusion coefficients of concrete specimens with various crack widths, a critical crack width and a critical crack depth are found out.

• Journal of the Korean Society of Hazard Mitigation
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• v.10 no.6
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• pp.147-154
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• 2010

In this study, flood control effects for infiltration trench which is one of runoff reduction facilities were analyzed based on hydraulic experiments. Hydraulic experiments were conducted using 25 cm diameter circular pipe, and water depths for boundary conditions are 5, 10, 15, 20, 25 cm. Infiltration volume, runoff volume, runoff initiation time, final infiltration capacity and final infiltration capacity reached time etc. were measured from infiltration trench hydraulic experiment. We assumed that drainage area of each infiltration trench is $130\;m^2$ ($6.5\;m{\times}20\;m$) and calculated CN with area based on those experimental characteristics. In AMC-I condition, the calculated CN with five water depths is 84 for 2% pipe slope, 83 for 5% pipe slope. In AMC-III condition, the calculated CN is 84 for 2% and 5% pipe slope.

• ETRI Journal
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• v.14 no.1
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• pp.40-51
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• 1992

$0.25{\mu} m$ 급 pMOSFET소자를 구현하기 위해, $P^+$ 폴리실리콘을 적용한 pMOS를 제작하였으며, $p^+$ 폴리실리콘 게이트 소자에서 심각하게 문제가 되고 있는 붕소이온 침투현상을 조사하고 붕소이온 침투가 일어나지 않는 최적열처리온도를 조사하였다. 소자제조 공정중 게이트 공정만 전자선 (EBML300)을 이용하여 직접묘사하고 그 이외의 공정은 stepper(gline) 을 사용하는 Mix & Match 방법을 사용하였다. 또한 붕소이온 침투현상을 억제하기 위한 한가지 예로서, 실리콘산화막과 실리콘질화막을 적층한 ONO(Oxide/Nitride/Oxide) 구조를 게이트 유전체로 적용한 소자를 제작하여 그 가능성을 조사하였다. 그 결과 $850^{\circ}C$의 온도와 $N_2$ 분위기에서 30분동안 열처리 하였을 경우, 붕소이온의 침투현상이 일어나지 않음을 SIMS(Secondary Ion Mass Spectrometer) 분석 및 C-V(Capacitance-Voltage) 측정으로 확인할 수 있었으며 그 이상의 온도에서는 붕소이온이 침투되어 flat band전압(Vfb)을 변화시킴을 알았다. 6nm의 얇은 게이트 산화막 및 $0.1{\mu} m$ 이하의 LDD(Lightly Doped Drain) $p^-$의 얇은 접합을 형성함으로써 소자의 채널길이가 $0.2 {\mu} m$까지 짧은 채널효과가 거의 없는 소자제작이 가능하였으며, 전류구동능력은 $0.26\muA$/$\mu$m(L=0.2$\mu$m, V$_DS$=2.5V)이었고, subthreshold 기울기는 89-85mV/dec.를 얻었다. 붕소이온의 침투현상을 억제하기 위한 한가지 방법으로 ONO 유전체를 소자에 적용한 결과, $900^{\circ}C$에서 30분의 열처리조건에서도 붕소이온 침투현상이 일어나지 않음으로 미루어 , $SiO_2$ 게이트 유전체보다 ONO 게이트 유전체가 boron 침투에 대해서 좋은 장벽 역활을 함을 알았다. ONO 게이트 유전체를 적용한 소자의 경우, subthreshold특성은 84mV/dec로서 좋은 turn on,off 특성을 얻었으나, ONO 게이트 유전체는 막자체의 누설전류와 실리콘과 유전체 계면의 고정전하량인 Qss의 양이 공정조건에 따라 변화가 심해서 문턱전압 조절이 어려워 소자적용시 문제가 된다. 최근 바닥 산화막(bottom oxide) 두께가 최적화된 ONO 게이트 유전체에 대하 연구가 활발히 진행됨을 미루어, 바닥 산화막 최적화가 된다면 더 좋은 결과가 예상된다.