• Proceedings of the Korean Nuclear Society Conference
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• 1996.05c
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• pp.513-518
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• 1996

저농도 방사성 액체폐기물의 최종 처리를 목적으로 본 연구에서는 면 35%와 Polyester 65%가 함유된 합성섬유를 증발매체로 하여 자연상태의 공기를 강제 송풍시키는 자연증발처리시설에서 증발에 영향을 미치는 주요 변수에 따라 증발 단위 면적당 Cs-137, Co-60을 함유한 방사성 폐액의 증발량측정 및 제염계수를 조사하였다. 증발효과는 유입공기의 습도가 낮고, 공기의 유속과 공급액의 유량이 증가하고 유입공기 및 폐액의 온도가 높아질수록 증발량이 증가하였다. 실험결과 유입된 공기는 1$0^{\circ}C$ 이상, 습도는 80% 이하, 공급폐액의 유량이 3.4 $\ell$/hr $m^2$ 이상, 공기유속은 1.14~l.47 m/sec 범위가 조업조건이며 이때 제염계수는 5.1 $\times$ $10^3$, 배출공기의 방사능 농도는 4.7$\times$$10^{-13}$ $\mu$Ci/$m\ell$ air로 측정되었다. 공급유량이 4.6$\ell$/hr.$m^2$와 공기유속이 1.47 m,/sec일때 최대 증발조건으로 나타났으며, 이때 증발량은 총 증발면적 11,250$m^2$ 에서 1.2 ㎥/hr로 측정되었으며 대기의 온.습도 및 풍속에 따른 실험을 통하여 달톤형 증발식의 Wind Factor ［Eh ＝ (0.0168 ＋ 0.0141V)$\Delta$H］를 도출하였다.

• The Journal of Engineering Geology
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• v.31 no.1
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• pp.67-81
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• 2021

Grouting is used for reinforcement and waterproofing of soft ground to increase its bearing capacity, reduce the impacts of rising or lowering groundwater levels, and reduce subsidence due to vibration and general causes. This study investigated the enhancement of grout strength and hardening time by the addition of reinforcing fibers, and the development of non-cement grouting materials from blast furnace slag. An experiment was performed to measure the increase in grout strength resulting from the addition of 0.5% increments of aramid and carbon reinforcing fibers. The results show that the uniaxial compressive strength of grout increases with increasing content of reinforcing fiber. Comparison of three admixtures of finely powdered blast furnace slag and 10%, 20%, and 30% calcium hydroxide stimulating agent showed that the uniaxial compressive strength of the mixture increases with increasing content of alkaline stimulant; however, the strength was lower than for 100% pure cement. The reaction of calcium hydroxide with blast furnace slag powder, which increases the strength of the grout, is more effective if injected as a solution rather than a powder.

• Composites Research
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• v.12 no.6
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• pp.8-14
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• 1999

This research is focused on the investigation of impact strength and the microscopic observation of material behavior of glass fiber reinforced polypropylene in solid phase forming. The fiber weight per-centage of the composite materials was 20%, 30% and 40%. The solid-phase formed specimens were pre-strained to 10%,20%. and 30% strain levels. The forming temperatures of specimens were $100^{\circ}C$, $125^{\circ}C$ and $150^{\circ}C$. Izod impact test was performed with unnotched specimens. With increasing the glass fiber content ; the impact strength was increased.

• Composites Research
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• v.23 no.3
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• pp.31-36
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• 2010

A new material, carbon-nanofiber/polypyrrole (CNF/PPy) composite films, with different CNF weight ratios were fabricated electrochemically. Compared to the fabrication process based on simple physical mixing, the flexibility of the new film has been improved much better than the previous similar material. Pure PPy films were also fabricated by the new electrochemical process for the comparison of difference. Several SEM images were taken at two locations (electrode-side and solution-side) and at the cross section of the samples. Electrical conductivity of the composite films was measured by the four-probe method. The conductivity of the pure PPy film 0.013cm thick was 79.33S/cm. The CNF/PPy composite film with 5% CNF showed a conductivity of 93S/cm. One with 10% CNF showed a conductivity of 126 S/cm. The conductivity of PPy improves, as the CNF weight ratio increases. The good conductivity of CNF/PPy composites makes them a candidate for a small bending actuator. A bending sensor consists of PPy and PVDF, which can be operated in the air, was designed and the bending deflection was calculated using FEM.

• Proceedings of the Korean Fiber Society Conference
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• 2001.10a
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• pp.211-214
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• 2001

최근 입자를 이용한 색전술의 재료로서 광범위하게 사용되는 폴리비닐알코올(poly (vinyl alcohol) (PVA)) 입자는 전형적인 혼성배열(atactic)이다[1]. 제조된 PVA 입자가 고내구성 및 혈액내에서 안정성을 나타내기 위해서는 중합된 PVA 입자의 분자량 뿐만 아니라 교대배열성(syndiotacticity)도 커야 한다. 교대배열기(sydiotactic group)를 풍부하게 함유하고 있는 고분자량의 PVA를 제조하기 위해서는 고분자량의 교대배열성 전구체가 얻어지도록 입체장애를 일으키는 에스테르기를 보유하고 있는 단량체를 사용하거나 중합방법을 개선하는 것이 필요하다. (중략)

• Journal of the Korea Convergence Society
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• v.11 no.6
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• pp.83-88
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• 2020

Recently, radiation shielding sheets made of eco-friendly materials have been widely used in medical institutions. The shielding sheet is processed into a solid form by thermoforming by mixing a shielding material with a polymer material. The base is resin-based and has a limit in tensile strength, and for this purpose, fibers such as non-woven fabrics are used on the surface. The shielding sheet process technology has a problem in that the tensile strength rapidly decreases when the content of the shielding material is increased to increase the shielding performance. In order to improve this, this study intends to compare and evaluate the method of laminating and coating the fibers in the sheet process. In comparison of the three types of sheets, there was no difference in shielding performance between the fiber-coated sheet and the compression sheet, but there was a large difference in tensile strength.

• Korean Journal of Soil Science and Fertilizer
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• v.33 no.2
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• pp.109-113
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• 2000

The purpose of this study was conducted to develop the slow-released N fertilizer(SRNF) using of waste paper cellulose. Properties of trial product was investigated. Contents of nitrogen, phosphorus, and potassium in trial product were showed 26%, 0.04 and 0.01%, respectively. The contents of Cr, Cu, Pb and Zn were showed 17.4ppm. 259ppm, 12.2ppm and 60.0ppm in the trial product, respectively. However, As and Cd was not detected. Nitrogen of SRNF could be released 60.4% within 12hr after dissolution in water. However, the releasing velocity was thereafter remarkably delayed, showing 75% after dissolution for 72hr.

• Korean Journal of Food Science and Technology
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• v.29 no.4
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• pp.648-656
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• 1997

Thermal treatment of soymilk residue was carried out at 140, 150, and $160^{\circ}C$ for possible use as a raw material for dietary fiber, and some physicochemical properties of the extracts were investigated. Soluble dietary fiber(SDF) content of the extracts prepared under optimal conditions was more than 30% suggesting the conversion of insoluble dietary fiber to SDF. The main sugar components of the extracts were glucose, galactose, and arabinose. Analysis of the moelcular weight distribution by high performance size exclusion chromatography revealed that the proportion of high molecular weight fraction decreased and that of middle-sized polymer increased as the extraction temperature increased. The viscosity of aqueous solution of the extracts decreased with an increase in extraction temperature, but showed no trend as pH changed. The solubility increased with extraction temperature showing the highest at $160^{\circ}C$. The extract at $140^{\circ}C$ had the biggest calcium-binding capacity, which correlated with the changes in viscosity.

• Journal of Nutrition and Health
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• v.26 no.2
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• pp.196-201
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• 1993

In this study, dietary fiber contents in vegetables and seaweeds were determined by Mongeau-Brassard method and the AOAC official method. The average total dietary fiber(TDF) contents by AOAC official method were 6% for vegetables, and 33% for seaweeds. The average ratios soluble dietary fiber (SDF) contents to TDF contents were 47% for vegetables and 57% for vegetables except bellflower root and 1.0% - 8.0% for seaweeds. TDF$\pm$error boundary values by Mongeau-Brassard method were a little higher than those by AOAC official method. But, F/Fc of all samples were lower than 1.0. Therefore, Mongeau-Brassard method was evaluated as precisely as AOAC official method.

• Proceedings of the Korean Society of Fisheries Technology Conference
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• 2003.05a
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• pp.101-102
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• 2003

갈조류의 세포막 또는 세포간물질로 함유되어 있는 다당류인 alginate는 독특한 물리화학적인 특성을 지니고 있어, 식품공업, 직물공업, 의약용, 용수처리, 도료공업등에 널리 사용되고 있으며, 또한 새로운 용도개발을 위한 연구도 많이 진행되고 있다. 식품산업에 이용되는 alginate는 주로 Na, K, NH$_4$$^{+}$, NH$_4$$^{+}$-Ca 및 Na-Ca염형태인데 이들 수용성 alginate는 분자량, Ca함량, 입자형태(구형 또는 섬유상), 입자크기, M(mannuronic acid)/G(guluronic acid)비들에 따라 다양한 물성을 나타낸다. (중략)