• Journal of the Korean GEO-environmental Society
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• v.1 no.1
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• pp.43-50
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• 2000

This paper presents the engineering property of light weight soil made of soil mixed with recycled stylofoam and stabilizer. Recycled stylofoam beads is able to use by lightweight fill materials because it is light, adiabatic, and effective for vibration interception. Especially, recycled stylofoam beads is easy to supply because stylofoam have been recycle item in 1996. In this study, physical and geotechnical properties of the light weight mixed soil(weathered granite soil mixed with Stylofoam Beads) were analyzed by laboratory experiments to examine its suitability for backfill materials. Laboratory tests were performed to evaluated strength, bearing capacity, weight, permeability, microphotograph analysis with variation of mixing ratio. Based on the results, it is concluded that the use of recycled stylofoam beads is acceptable lightweight fill.

• Journal of the Korea Convergence Society
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• v.11 no.10
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• pp.219-224
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• 2020

Industrial mixers to homogeneously blend particulate materials have been developed and widely used in various industries. However, most industrial mixers have at most two-degree-of-freedom for the operation, which limits the range of operation parameter selection for optimal blending. This paper proposes a multi-degree-of-freedom robotic mixer designed by converging a conventional drum blender and a robotic manipulator and evaluated its performance in a virtual operating environment. Discrete element simulations were conducted for mixing performance evaluation. The numerical results showed that the proposed mixer design exhibits a better mixing performance than conventional ones.

• Horticultural Science & Technology
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• v.18 no.4
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• pp.508-512
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• 2000

Growth of red pepper (Capsicum annuum) 'Kumtap', tomato (Lycoperisocon esculentum) 'Seokwang', petunia (Petunia hybrida) 'Madness Rose', and pansy (Viola tricolor) 'Magestic Giant' in mixtures of chestnut woodchips and granular rockwool at 25:75, 50:50, or 75:25 (v/v) was examined. Chestnut woodchips were soaked in water for 48 hours or aged in open field for 6 months in order to remove substances impeding plant growth. A commercial plug medium was used as the control. All treatments showed in a similar result in red pepper, petunia, and pansy. Plant height, fresh weight, dry weight, and chlorophyll content in media containing chestnut woodchips, especially in higher proportions, were poorer as compared to those in the control. On the contrary, height, fresh weight, and dry weight of tomato seedlings in media containing woodchips were significantly higher than those in the control. For petunia, pansy, and red pepper, six month ageing in open field of woodchips was more favorable for growth than 48 hour water soaking. Emergance of petunia seed was inferior, especially when woodchip content was higher, to the other crops with a resultant growth suppression. From the results, chestnut woodchips proved to be a practical material as a medium component only in tomato plants.

• Proceedings of the Korean Vacuum Society Conference
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• 2011.08a
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• pp.272-272
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• 2011

무기물 나노입자를 포함하는 유기물/무기물 나노복합체는 차세대 전자 소자에 쉽게 적용이 가능하고 응용 잠재적 능력이 뛰어나기 때문에 차세대 비휘발성 메모리 소자에 응용하려는 연구가 세계적으로 활발히 진행되고 있다. 본 연구에서는 poly (methylmethacrylate) (PMMA) 절연성 고분자 박막 안에 CdTe와 CdTe-CdSe 코어-쉘 나노입자를 각각 분산시켜 이를 전하의 저장 매체로 사용하는 메모리 소자를 제작하였다. 제작된 각각의 소자에 대한 메모리 메카니즘과 PMMA 박막 안에 분포되어 있는 CdTe-CdSe 코어-쉘 나노입자에서 CdSe 쉘의 전기적 영향에 대하여 연구하였다. 소자에 필요한 용액을 제작하기 위해 서로 다른 용매에 녹아 있는 CdTe-CdSe 나노입자와 PMMA를 혼합하였다. Al 금속을 하부 전극으로 증착한 p-Si (100) 기판 위에 나노입자와 PMMA가 혼합된 용액을 스핀 코팅 방법을 사용하여 박막을 형성한 후, 남아있는 용매를 제거하기 위해 열처리를 하였다. 용매가 모두 제거된 박막위에 금속 마스크를 사용하여 상부 Al 전극을 열증착 방법으로 형성하였다. 나노입자가 포함된 고분자 박막의 메모리 특성을 비교하기 위하여 나노입자가 없는 PMMA층만으로 형성된 소자도 같은 방법으로 제작하였다. 세 가지 종류의 소자에 고주파 정전용량-전압 (C-V) 측정을 한 결과 나노입자가 분산된 PMMA 층으로 제작된 소자에서만 평탄 전압 이동이 관찰되었으며, 이것은 나노입자를 전하 포획 장소로 사용할 수 있다는 것을 확인하였다. 정전용량-시간 (C-t) 측정을 하여 나노입자가 포함된 PMMA 층으로 제작된 메모리 소자의 안정성을 관찰하였다. C-V와 C-t 측정 자료를 바탕으로 제작된 메모리 소자의 메모리 메카니즘과 CdTe-CdSe 코어-쉘 나노입자에서 CdSe 쉘의 역할을 설명하였다.

• Korean Journal of Materials Research
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• v.5 no.4
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• pp.426-432
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• 1995

윤활제인 zinc stearate의 첨가량 (0~4wt%)을 변화시켜 U$O_{2}$분말의 겉보기밀도, 성형시의 분말입자간 마찰과 입자/다이벽 마찰간의 상관관계를 조사하였다. 소량의 윤활제 첨가시에는 U$O_{2}$분말입자간 박막의 윤활제 도포층이 형성되어 겉보기밀도가 증가한 반면 다량의 윤활제를 첨가한 경우에는 U$O_{2}$ 분말입자에 두꺼운 윤활제 도포층이 형성되고 미혼합된 윤활제가 존재하여 겉보기밀도는 감소하는 경향을 보였다. 윤활제를 첨가혼합한 상태에서 다이벽 윤활도포 유무에 따라 구한 U$O_{2}$ 성형체의 성형압력/성형밀도 자료로부터 분말입자간 마찰, 입자/다이벽 마찰 그리고 성형시 lubrication/inhibition등의 상대적 중요성을 조사하였다. 입자/다이벽 마찰에 의한 압력손실은 입자간 마찰에 의한 압력손실보다 크게 나타났다. 입자/다이벽 마찰에 의한 압력손실은 다이벽 윤활제 도포에 의해 최소화될 수 있지만 상대적으로 바람직하지 않은 성형시의 inhibition이 야기되는 것으로 나타났다.

• Proceedings of the KSME Conference
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• 2001.06e
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• pp.94-99
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• 2001

The numerical simulation of the particle dispersion in the vortical flows provides insight into the mechanism of particle-fluid interaction. The simulation results show that the mixing layers are characterized by the large-scale vortical structures undergoing pairing process. The particle dispersion is strongly influenced by the large-scale structures and the particle sizes. The analysis shows that the mixing layers grows like a step-function.

• Proceedings of the KSME Conference
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• 2005.11a
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• pp.100.2-100.2
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• 2005

• Proceeding of EDISON Challenge
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• 2013.04a
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• pp.193-202
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• 2013

본 연구는 두개의 서로 다른 LJ 입자가 혼합된 계에 대하여 이들 사이의 LJ parameter 변화가 어떠한 영향을 미치는지 모의실험을 하였다. 조사 대상은 비활성 기체인 He과 Xe을 기준으로 하여 이들의 LJ parameter를 기준값으로부터 일정하게 변화시키며 열용량을 관찰하여 진행하였다. 분자간 상호작용만을 고려하여, 단원자 기체인 비활성 기체의 Lennard-Jones potential energy를 구하였다. Epsilon 값과 sigma 값을 바꿔 Lennard-Jones potential energy의 변화를 알아보고자 한다. 본 연구를 통해 sigma, epsilon 값이 클수록 Lennard-Jones potential energy가 커진다는 것을 알 수 있었다.

• 한국해양학회지
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• v.30 no.4
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• pp.288-301
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• 1995

Rates of the sedimentation and particle mixing have been estimated by applying uranium-series disequilibrium techniques to three sediment cores collected from the korea Deep Ocean Study (KODOS) site between the clarion and Clipperton Fracture Zones (CCFZ) of the Equatorial Pacific. Sedimentation rates based on the profiles of excess /SUP 230/Th activity and /SUP 230/ Th/SUB xs//SUP 232/ Th activity ratios at the southeastern part of the study area were estimated to be in the order of a few millimeters per thousand year, while at the northwestern part a factor of ten lower. Excess activities of /SUP 230/Th and /SUP 230/Th ratios showed intervals of constant values in the upper part of the sediment cores, probably generated by biological particle mixing. A "two-box" advection-diffusion steady state mixing model was employed in order to estimate particle mixing rates in the upper and the lower layers, based on the distribution profiles of excess /SUP 210/Pb activities. Particle mixing coefficients were estimated to be in the order of 10$^1$ cm$^2$/y in the upper layer and 10/SUP -1/-10/SUP 0/ cm$^2$/y in the lower layer.

• Applied Chemistry for Engineering
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• v.18 no.6
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• pp.636-642
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• 2007

Software program to predict the packing density of multi-sized and multi-component particulate system was developed. For this purpose, the experiment to measure the packing density of AP (ammonium perchlorate) and Al (aluminum) particles with different sizes and their mixtures was carried out. The packing densities obtained from various experiments were compared with the predicted data from the developed software program. In the case of the packing density of the binary system, which is comprised of two different size particles and/or two different components, the relative errors were ranged 0.25~13.13%, and in the same venue the relative errors of the ternary system were 0.25~13.13%. Agreement between experimental data and the predicted results is reasonably accurate. In order to achieve the targeted packing density, the software program calculated the contour of the component particles and this will contribute the formulation of optimal packing systems.