• Transactions of Materials Processing
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• v.1 no.2
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• pp.14-19
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• 1992

분말단조 공정의 해석을 위한 기초연구로서 고용 업셋에 의한 다공질 합금강 프리폼의 치밀화와 소성 변형거동에 관하여 조사하였다. 다공질 프리폼의 소성 유동응력은 용도의 상승에 떠라 감소하였고, 변형속도의 증가에 따라 증가함을 보였다. 또한, 다공질 프리폼의 초기밀도가 더 높을수록 동일한 온도와 하중조건에서 더 높은 치밀화를 보였다. 또한, 밀도변화에 따른 프와송 비를 실험치로 부터 구하였고, 배불림 현상과 체적변화를 고려하여 온도에 따른 진응력-진변형률 관계를 구하였다.

• Journal of the Korean GEO-environmental Society
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• v.4 no.1
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• pp.5-10
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• 2003

The solids and the fluids in porous media have a relative velocity to each other. Due to physically and chemically different material properties and their relative velocity, the behavior of saturated porous media is extremely complicated. Thus, in order to describe and clarify the deformation behavior of saturated porous media, constitutive models for deformation of porous media coupling several effects need to be developed in frame of Arbitrary Lagrangian Eulerian(ALE) description. The aim of ALE formulations is to maximize the advantages of Lagrangian and Eulerian elements, and to minimize the disadvantages. Therefore, this method is appropriate for the analysis of porous media which are considered for the behavior of the solids and the fluids. For this reason, mass balance equations for saturated porous media are derived here in ALE description frames. ALE formulations of mass conservation for the solid phase and the fluid phase are expressed. Then, linear momentum balance equation for porous media as multiphase media is expressed.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.19 no.6
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• pp.293-297
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• 2009

In this paper, we made three kinds of porous silicon samples (single layer, distributed Bragg reflector, and microcavity) by electrochemical etching p-type silicon substrate. And then, we investigated their reflectance spectrum properties. We found that the number of fringe patterns and the maximum reflectivity of porous silicon multilayer increased compared with a porous silicon sinlge layer. In addition, we can observe that the DBR (distributed Bragg reflector) porous silicon has a full-width at half-maximum about 33 nm which is narrower than the porous silicon single layer and porous silicon microcavity.

• Proceedings of the KIEE Conference
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• 2001.07c
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• pp.1902-1904
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• 2001

본 논문은 마이크로머시닝 기술을 응용하여 다공질 실리콘 다이어프램을 제작하여 air, $N_2$, Ar 분위기에서 유리로 패키징하였다. 유리로 패키징된 소자들과 유리 패키징을 하지 않는 소자를 시간 경과에 따른 다공질 실리콘의 PL(Photoluminescence) 스펙트럼 (peak wavelength, intensity)과 저항 변화를 측정하였다. 또한, 패키징 분위기에 따른 다공질 실리콘의 aging 효과를 서로 비교하여 다공질 실리콘 다이어프램을 이용한 PIN 구조의 소자를 광센서로써 응용 가능성을 살펴보았다.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.9 no.1
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• pp.89-93
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• 1999

The properties and effects of the electrodeposited CdTe compound film on the porous silicon. To find ways to achieve good mechanical contact on the nanostructure porous silicon layer while keeping the interface transparent, we tried to electrodeposit a CdTe compound film on the porous silicon surface. The CdTe compound film was fabricated with -2.3V vs. Ag/AgCl potential difference in the electrolyte solution containing 1M of $CdSO_4$and 1 mM of $TeO_4$. X-ray diffraction results confirmed the existence of CdTe compound film on the porous silicon surface. Auger depth profile showed that Cd and Te were uniformly distributed up to a 80 nm distance from the surface. The photoluminescence of the sample with a CdTe compound film was weaker in intensity than that without the film and the maximum wavelength was shifted to the higher energy. These results indicate that the contacting CdTe compound film was infiltrated to the nanostructure of porous silicon.

• Korean Journal of Materials Research
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• v.4 no.4
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• pp.379-384
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• 1994

Room-temperature photoluminescent porous Si has been formed by etching Si wafer u-ith the solution of $HF:HNO_{3}: H_{2}O$=l : 5 : 10. We have observed photoluminescence(PL) spectra similar to those reported recently for porous-Si films formed by anodic etching with HF solutions. We have also investigated the dependence of PI, spectra on the etching time which was varied from 1 to 10 minutes. We found that 5-minute etching gave us the strongest PL intensity. We also found by atomic force microscopy( AFM) measurements that the surface fearure size became smaller for longer etching time and the average feature size of the etched Si wafer for 5-minute was about 1, 500~2, 000$\AA$. This indicates that the surface feature of the etched porous Si affects the PL intensity of the sample.

• Journal of Korean Society of Coastal and Ocean Engineers
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• v.27 no.1
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• pp.9-13
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• 2015

Field experiment were carried out to investigate the formation of ground water flow and remediation of muddy tidal flat by installation of porous pile at the tidal flat of brackish river located in Hiroshima City, Japan. After the installation of porous pile, the concentrations of Dissolved Oxygen (DO) in the interstitial water in the porous pile increased with maximum concentration of 4 mg/L due to a formation of groundwater flow. It was observed that a increase in Oxidation Reduction Potential (ORP) and a decrease in Ignition Loss (IL) in the porous pile site and these must be caused by the increase of dissolved oxygen in the interstitial water. From these results obtained above, it is concluded that the porous pile is an effective technology for remediation of muddy tidal flats.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.41 no.4
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• pp.229-238
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• 2017

This study started to deduce a permeability relationship that can consider the geometric features of various porous media under different flow regimes. With reference to the previous works of Kozeny and Carman, the conventional Darcy-Weisbach relation (Darcy's friction flow equation) was reviewed and expanded for porous flow analysis. Based on the capillary model, this relation was transformed to the friction equivalent permeability (FEP) definition. The validity of the FEP definition was confirmed by means of comparison with the Kozeny-Carman equation. Hereby, it was shown that the FEP definition is the generalized form of the Kozeny-Carman equation, which is confined to laminar flow through a circular capillary. In conclusion, the FEP definition as a new permeability estimation method was successfully developed by expanding the Darcy-Weisbach relation for porous flow analyses.

• Journal of the KSME
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• v.51 no.1
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• pp.38-42
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• 2011

이 글에서는 독일 특히 드레스덴의 Fauhofer IFAM 연구소에서 개발하였거나, 진행 중인 여러 가지 다공질 금속의 현황과 응용에 대하여 소개한다.

• Proceedings of the Korean Society of Dyers and Finishers Conference
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• 2003.04a
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• pp.101-107
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• 2003

국내에서는 90년대 후반 이후부터 건식코팅 중 제조공정이 단순하고 제조비용의 부담이 적으며 생산속도가 빠른 친수성 폴리우레탄 수지를 사용한 비다공질 투습방수포가 점차 확대되어 일반적으로 많이 제조되어지고 있다. 친수무공형 투습방수포는 다공질형의 투습방수포와는 달리 연속적인 비다공질의 solid한 코팅 층으로 구성되어진다. 이러한 비다공질 막은 물에 대하여 내수압이 뛰어나며 투습도는 친수성 피막의 두께에 반비례하는 특징을 가지고 있다. (중략)