c-$\phi$ 지반에서의 아칭현상을 고려한 원형수직터널 토압 : II. 실내 모형실험

김도훈,차민혁,이대수,김경렬,이인모,Kim, Do-Hoon,Cha, Min-Hyuck,Lee, Dea-Su,Kim, Kyung-Ryeol,Lee, In-Mo 한국터널지하공간학회 2010 한국터널지하공간학회논문집 Vol.12 No.2

원형수직터널에 작용하는 토압은 아칭효과로 인해 2차원 일반 흙막이벽에 작용하는 토압보다 작으므로 원형수직터널 설계 시 벽체에 작용하는 실질적인 토압의 예측이 필요하다. 본 논문은 두 개의 연속된 논문(Companion papers)의 두번째로서 원형수직터널 설계 시 건조한 사질토뿐만 아니라 c-$\phi$ 지반과 다층지반에서 적용 가능하도록 새롭게 제안된 토압식(김도훈 등, 2009)을 증명하기 위해 대형 모형실험을 수행하였다. 고안된 모형실험 장비는 단계별 굴착이 가능하도록 제작 벽체의 반경을 변화시켜가며 실험을 수행하였다. 또한 강사 방법으로 지반을 조성하기 전 건조한 시료에 물을 첨가하고 불포화사질토를 형성시켜 겉보기 점착력을 발현시킴으로써 c-$\phi$ 지반과 다층지반에서 실험을 진행하였다. 실험 결과로서, 단계별 굴착을 모사하였을 때, 아칭효과에 의해 굴착된 지반에서 굴착되지 않은 지반으로 하중이 전이가 일어나는 확인할 수 있었다. 또한, 동시에 굴착했을 때의 토압은 예측한 값에 비해 상당히 작게 나타났지만, 단계별로 굴착했을 때의 최종 토압은 동시 굴착 시의 토압에 비해 크게 나타나며 새롭게 제안된 토압식과 잘 일치하였고 c-$\phi$ 지반과 다층지반에서 수행한 실험의 결과도 겉보기 점착력의 효과로 인해 토압의 감소를 보이며 이론적인 값과 잘 일치하는 것으로 나타났다. The earth pressure acting on the vertical shaft is less than that acting on the retaining wall due to three dimensional arching effect. Thus, it might be essential to estimate the earth pressure actually acting on the shaft when designing the vertical shaft. In this paper, large-sized model tests were conducted as Part II of companion papers to verify the newly suggested earth pressure equation proposed by Kim et al. (2009: Part I of companion papers) that can be used when designing the vertical shaft in cohesionless soils as well as in c-$\phi$ soils and multi-layered soils. The newly developed model test apparatus was designed to be able to simulate staged shaft excavation. Model tests were performed by varying the radius of vertical shaft in dry soil. Moreover, tests on c-$\phi$ soils and on multi-layered soils were also performed; in order to induce apparent cohesion to the cohesionless soil, we add some water to the dry soil to make the soil partially-saturated before depositing by raining method. Experimental results showed a load transfer from excavated ground to non-excavated zone below dredging level due to arching effect when simulating staged excavation. It was also found that measured earth pressure was far smaller than estimated if excavation is done at once; the final earth pressure measured after performing staged excavation was larger and matched with that estimated from the newly proposed equation. Measured results in c-$\phi$ soils and in multi-layered soils showed reduction in earth pressures due to apparent cohesion effect and showed good matches with analytical results.

[ESSAY] 불멸의 캣 타워 : 김도훈의 집과 낭만 41

김도훈,심효진(편집자) 주식회사 시사저널이코노미 2025 리빙센스 = Living Sense Vol.7 No.-

(주)아르스프락시아 김도훈 대표 인터뷰

김도훈 한국공학교육학회 2017 Ingenium(人材니움) Vol.24 No.2

(주)아르스프락시아 김도훈 대표 인터뷰

김도훈,한경희 한국공학교육학회 2017 공학교육동향 Vol.24 No.2

2P-401 All inorganic cesium lead halide perovskite solar cells for tandem cell

김도훈,임상혁 한국공업화학회 2017 한국공업화학회 연구논문 초록집 Vol.2017 No.1

Tandem solar cells have great potential for increasing the efficiency with minimal cost. Lead halide based organic-inorganic hybrid perovskite materials have been considered as promising candidate for tandem cells. However, these materials generally are composed of organic cations such as methylammonium or formamidinium, they undergo compositional degradation due to humidity and heat. Cesium lead halides are prospective alternative due to its suitable band gap, high absorption and thermal stability. Cesium lead iodide is stable in an orthorhombic structure at room temperature, and when heated above 300℃, it changed to cubic structure. Unfortunately, the cubic phase is not stable in ambient atmosphere due to humidity and temperature. Therefore, the manufacture of high phase stability with suitable bandgap for tandem solar cells is still challenging, so we substituted iodine with a dash of bromide source to solve the structural instability with minimal band edge shift.

Compositionally Stable All-Inorganic Cesium Lead Halide Perovskites Solar Cells with Bandgap Tuning

김도훈,허진혁,임상혁 한국공업화학회 2018 한국공업화학회 연구논문 초록집 Vol.2018 No.1

Inorganic CsPbI2Br metal halide perovskite optoelectronic devices with high thermal stability

김도훈,허진혁,임상혁 한국공업화학회 2019 한국공업화학회 연구논문 초록집 Vol.2019 No.1

Although organic/inorganic hybrid metal halide perovskite solar cells have high power conversion efficiency over 25 % at 1 sun, they still have poor thermal stability to find commercial applications. Therefore, all inorganic metal halide perovskite solar cells have been of great interest as promising candidate to solve such weak thermal stabilities of hybrid metal halide perovskite materials. In parallel, the material cost is also big obstacle to realize high efficiency and low cost perovskite solar cells because the hole transporting materials are relatively very expensive. In this regard, here we would like to report on highly efficient and thermally stable inorganic CsPbI₂Br mesoscopic metal halide perovskite solar cells with relatively cheap poly-3-hexylthiophene (P3HT) hole transporting layer with 7.56 % of degradation after 1000h under 100 °C/25 % RH and 1 sun light soaking condition.

종이 재활용 과정에서 아밀레이즈가 표면처리용 형광증백제에 미치는 효과

김도훈,이지영,조해민,이연희 한국공업화학회 2021 한국공업화학회 연구논문 초록집 Vol.2021 No.1

Hysteresis-less inorganic CsPbI2Br metal halide perovskite optoelectronic devices with high open circuit voltage

김도훈,허진혁,임상혁 한국공업화학회 2019 한국공업화학회 연구논문 초록집 Vol.2019 No.1

Although organic/inorganic hybrid metal halide perovskite solar cells exhibit high power conversion efficiency over 25 % at 1 sun, they still have weak thermal stability to find commercial applications such as building integrated photovoltaics, vehicle integrated photovoltaics, and tandem devices. Therefore, all inorganic metal halide perovskite solar cells have been of great interest as promising alternative to solve such weak thermal stabilities of hybrid metal halide perovskites. Here, we would like to report on high-performance and hysteresis-less mesoscopic CsPbI₂Br perovskite solar cells by adapting hole-transporting materials (HTMs) with controlled highest occupied molecular orbital (HOMO) values. We obtained open-circuit voltage of 1.31 V and power conversion efficiency of 14.86% with exhibiting ~10 % degradation under continuous 1 sun light soaking at 85 °C for 1000 h.

Synthesis of large-sized two-dimensional α-MoO₃ van der Waals crystals by TiO₂ assisted selective facet passivation and their application to lustering pigments

김도훈,문상화,임상혁 한국공업화학회 2019 한국공업화학회 연구논문 초록집 Vol.2019 No.1

Large-sized α-MoO₃ nanoplates were synthesized by introduction of titanium tetra isopropoxide as TiO₂ precursor in hydrothermal solution chemistry. During the hydrothermal synthesis, the TiO₂ can be selectively deposited on the (001) facets of h-MoO₃ hexagonal rods and on the (001) and/or (010) facet of α-MoO₃ re-growing crystals due to the small lattice mismatch between them. Owing to the TiO₂ passivation of the surface of h-MoO₃ rods, the h-MoO₃ rods are changed to MoO₃ tubes because the h-MoO₃ are dissolved from the inner part of the TiO₂ passivated h-MoO₃ rods. The TiO₂-passivated (001) facets of h-MoO₃ rods act as templates for the re-growth of α-MoO₃ and consequently produced rectangle-shaped α-MoO₃ nanoplates. Simultaneously, the TiO₂ passivated on the (001) and/or (010) facet of the re-growing α -MoO₃ crystals inhibits the preferred crystal growth to [001] direction and promoted the crystal growth to [100] direction, thereby yielding plate-shaped α-MoO₃.