• 한국염색가공학회지
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• 제4권3호
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• pp.74-81
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• 1992

Chemical bonded nonwoven fabric for apparel use and spunlaced nonwoven fabric for medical use were finished for soil resistance and blood replellency with fluorochemicals utilizing foam finishing technology (FFT) and conventional padding application techniques. The FFT process improved soil and abrasion resistance properties of nonwoven fabrics compared with the conventional padding process. Excellent water-oil-saline-alcohol repellency values and water impact penetration values were obtained in the spunlaced nonwoven fabrics with both techniques.

• 한국재료학회지
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• 제22권6호
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• pp.309-315
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• 2012

Metal foam has many excellent properties, such as light weight, incombustibility, good thermal insulation, sound absorption, energy absorption, and environmental friendliness. It has two types of macrostructure, a closed-cell foam with sealed pores and an open-cell foam with open pores. The open-cell foam has a complex macrostructure consisting of an interconnected network. It can be exploited as a degradable biomaterial and a heat exchanger material. In this paper, open cell Mg alloy foams have been produced by infiltrating molten Mg alloy into porous pre-forms, where granules facilitate porous material. The granules have suitable strength and excellent thermal stability. They are also inexpensive and easily move out from open-cell foamed Mg-Al alloy materials. When the melt casting process used an inert gas, the molten magnesium igniting is resolved easily. The effects of the preheating temperature of the filler particle mould, negative pressure, and granule size on the fluidity of the open cell Mg alloy foam were investigated. With the increased infiltration pressure, preheat temperature and granule sizes during casting process, the molten AZ31 alloy was high fluidity. The optimum casting temperature, preheating temperature of the filler particle mould, and negative pressure were $750^{\circ}C$, $400-500^{\circ}C$, and 5000-6000 Pa, respectively, At these conditions the AZ31 alloy had good fluidity and castability with the longest infiltration length, fewer defects, and a uniform pore structure.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2004년도 추계학술대회 논문집
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• pp.55-59
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• 2004

Recently, life cycle and lead-time of products have been shortened with the demand of customers. Therefore, it is important to reduce time and cost at the step of manufacturing trial molds. In order to realize three dimensional shape on CAD, the machining process has been widely used because it offers practical advantages such as precision and versatility. However, traditional machining process spends a lot of time in cutting product and the remained material causes trouble such as inconvenience for clean. In this work, a new machining process using the hot tool has been proposed to overcome those limitations. In the process, the hot tool moves the predetermined path and the heat of the tool decomposes the remained material. In order to set up the process, the hot tool to satisfy requirements is designed and the material thermal properties are obtained using the DSC and TGA machine. The relationships between process parameters and thermal radius of the tool are obtained through experiment.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2000년도 추계학술대회 논문집
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• pp.763-766
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• 2000

Rapid Prototyping(RP) techniques have their unique characteristics according to the working principles: stair-stepped surface of parts due to layer-by-layer stackin, low build speed caused by line-by-line solidification to build one layer, and additional post processing to improve surface roughness, so it is required very high cost to introduce and to maintain RP apparatus. The objective of this study is to develop software for automatic generation of unit shape part (USP) for a new RP process, Variable Lamination Manufacturing using linear hotwire cutting technique and expandable polystyrene foam sheet as part material (VLM-S). In order to examine the applicability of the developed software to VLM-S, USP's of general three-dimensional shapes, such as an auto-shift lever knob and a pyramid shape were generated.

• 한국분말야금학회:학술대회논문집
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• 한국분말야금학회 2006년도 Extended Abstracts of 2006 POWDER METALLURGY World Congress Part 1
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• pp.95-96
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• 2006

Stainless steel sludge is generated as a waste in the grinding process, and the possibility of recycling stainless steel is considered here. In this study, we considered the possibility of using the stainless steel sludge as metal powder for MIM or raw material for metal foam. For the MIM process, the metal powder will need some improvement, and flotation and spheroidizing processes of the sludge are necessary. For fabrication of the metal foam, untreated sludge can be used, and steel foam about 90% porosity is produced.

• 한국응용과학기술학회지
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• 제38권5호
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• pp.1219-1228
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• 2021

친환경적 바이오 계면활성제의 하나인 람노리피드(rhamnolipid)의 제조는 Pseudomonas aeruginos 계열의 박테리아가 가장 많이 사용되며, 바이오 공정을 통해 생산된다. 람노리피드의 화학구조는 rhamnose당과 𝛽-hydroxylated fatty acid의 결합으로 이루어져 있으며, 바이오 공정을 통해 동질체 혼합물 형태로 생산된다. 발효(fermentation)공정 중 거품 제어가 수율을 결정하는 가장 중요한 요인으로 알려져 있다. 본 논문에서는, 박테리아 내부에서 일어나는 람노리피드 합성 메카니즘을 소개하였고, 발효공정에서 문제점으로 인식되었던 거품 제어 방법에 대한 최근 시도들을 살펴보았다. 10년 전과 비교하여, 람노리피드 양산화 가능성은 빠르게 높아지고 있다. 특히, 람노리피드와 같은 바이오 계면활성제는 의약품과 같은 고부가가치 제품으로 응용된다면, 시장의 요구가 더 커질 것으로 기대한다.

• 한국산학기술학회논문지
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• 제7권3호
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• pp.458-464
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• 2006

토양의 생물학적 복원은 산업화로 무차별하게 오염되어 있는 국내 산업단지 주변과 지하수 환경보전을 위한 경제적 도구로 인식되어왔다. 본 연구는 친환경적 생물복원을 위한 기초자료를 얻기 위하여 유류로 오염된 양토에서 Pseudomonas sp. (KCCM 40055)를 접종한 polyurethane 매체환경을 적용, 유류의 성분중 PAH 분해도를 조사하였다. 다공성 매체로서 재현성이 뛰어나며 미생물 부착에 활용되어 온 polyurethane foam을 사용하여 미생물 부착성을 아울러 조사하였다. 사용된 PU중 최저공극 foam인 SR9-35C/G 의 경우 부착률과 PAH분해율이 가장 높았으며 토양함수율 증가에 따라 그 효율이 증가하였다.

• Computers and Concrete
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• 제20권3호
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• pp.263-273
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• 2017

An experimental investigation is carried out on the failure mechanism of foam concrete with cold formed steel double C-Channels embedment. The foam concrete is made of cement and fly ash with a compressive strength between 9 and 24 MPa with different densities. Forty-eight tests have been carried out in four groups of specimens with various embedment depths of the steel in the concrete. Four modes of failure are observed, which include the independent failure of the C-Channels with and without a concrete block inside the channel as well as the combined failure of the two channels, and the failure of the extrusion block. A theoretical model has been developed to understand the failure process. The peak compressive force applied onto the C-Channels that causes failure is calculated. It is concluded that the failure involves independent slippage between two C-Channels, and the steel and the foam concrete blocks inside the C-Channels. A method to calculate the peak force is also developed based on the test results. The calculations also show that the shear strength of the foam concrete is about 8% of the compressive strength with ${\alpha}$ coefficient of 0.4 between the steel and concrete.

• Advances in Computational Design
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• 제1권2호
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• pp.139-154
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• 2016

The usage of sandwich structure is extensively increasing in lightweight protective structures due to its low density and other useful properties. Sandwich panels made of metal sheets with unfilled cellular cores are found to exhibit lower deflections by comparing to an equivalent monolithic plate of same metal and similar mass per unit density. However, the process of localized impact on solid structures involving plastic deformation, high strain rates, temperature effect, material erosion, etc. does not hold effectively as that of monolithic plate. In present work, the applications of the sandwich plate with corrugated core have been extended to develop optimized lightweight armour using foam as medium of its core by explicit finite element analysis (FEA). The mechanisms of hardened steel projectile penetration of aluminum corrugated sandwich panels filled with foams have been numerically investigated by finite element analysis (FEA). A comparative study is done for the triangular corrugated sandwich plate filled with polymeric foam and metallic foam with different densities in order to achieve the optimum penetration resistance to ballistic impact. Corrugated sandwich plates filled with metallic foams are found to be superior when compared to the polymeric one. The optimized results are then compared with that of equivalent solid and unfilled cores structure to observe the effectiveness of foam-filled corrugated sandwich plate which provides an effective resistance to ballistic response. The novel structure can be the alternative to solid aluminum plate in the applications of light weight protection system.

• 한국재료학회지
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• 제32권2호
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• pp.85-93
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• 2022

Porous mullite-corundum ceramics were prepared using organic foam impregnation method with alumina and silica as raw materials. The influence of alkaline treatment and surfactant modification on polyurethane foam were studied. Effects of sintering process and material composition on porous mullite-corundum ceramics were investigated. The results show that the hang-pulp quantity of polyurethane foam increases with alkaline treatment. After treatment with 3 wt% SDS solution, the hang-pulp quantity of polyurethane foam further improved. Open porosity of sample decreased with elevation of sintering temperature and holding time, and compressive strength of sample showed a trend opposite to the change of porosity. The open porosity of the sample was enhanced by the increase of m(Al₂O₃/SiO₂); the compressive strength decreased with increase of m(Al₂O₃/SiO₂). However, when m(Al₂O₃/SiO₂) was 2.5, the compressive strength of the sample reached 6.23 MPa, and the open porosity of the sample was 80.7 %.