• 한국콘크리트학회:학술대회논문집
• /
• 한국콘크리트학회 2001년도 봄 학술발표회 논문집
• /
• pp.707-714
• /
• 2001

This paper presents the fundamental study on rational manu(acture of Very High Strength(VHS) concrete using industrial by-products as like silica fume, slag and fly ash. In this study, we had tested various mixing cases to manufacture the VHS concrete(target compressive strength : over 1,000 kgf/$cm^{2}$) which is easily workable (target slump flow : 60$\pm$l0cm), The main variables studied are; 1) test variables to find the optimum replacement ratio of mineral admixture, 2) test variables to find a rational water-binder ratio, a proper binder content, 3) test variables to find the method for reduction of slump loss, 4) test variables to know the influence of air entrainment on frost resistance. From the test results, it is concluded that the rational mix design can be made by using 40% slag, 10% silica fume, and water reducing agent(slump loss reduction type). We found that it is unnecessary to entrain air for freeze-thawing resistance.

• 식물조직배양학회지
• /
• 제22권1호
• /
• pp.1-5
• /
• 1995

벼의 인공종자를 무균상에서 건조시킴으로써 건조형 인공종자를 제조하였다. 1/2 MS배지에서 80%의 수분 손실률을 가진 인공종자는 20%가 발아하였다. 0.1 mg/L ABA가 첨가된 알긴산용액으로 제조한 인공종자는 0-90%의 수분손실률에서 최고 1.7배까지 발아율이 향상되었다. 이러한 결과는 ABA가 인공종자의 제조 및 건조과정에서 물리적 혹은 생리적인 저해에 대한 보호기능을 나타낸 것으로 사료된다.

• 한국원자력학회:학술대회논문집
• /
• 한국원자력학회 1997년도 춘계학술발표회논문집(1)
• /
• pp.514-519
• /
• 1997

The MRX is an integral type ship reactor with 100 MWt power, which is designed by Japan Atomic Energy Research Institute. It is characterized by integral type PWR, in-vessel type control roe drive mechanism, water-filled containment vessel and passive decay heat removal system. Marine reactor should have high passive safety. Therefore, in this study, we simulated the loss of flow accident to verify the passive decay heat removal by natural circulation using RETRAN-03 code. auxiliary feed water systems are used for decay heat removal mechanism and results are compared with the loss of flow accident analysis using emergency decay heat removal system by JAERI. Results are very similar to case of EDRS 1 loop operation in JAERI analysis and decay heat is successfully removed by natural circulation.

• 한국전기전자재료학회논문지
• /
• 제26권9호
• /
• pp.656-661
• /
• 2013

In this study, the moisture content, charge discharge current, electrostatic capacity and dielectric loss tangent are measured for the specimen of bisphenol type epoxy resin which is mixed with squared amorphous silica filler and dipped in hot water of $50^{\circ}C$ for 169 days. The results of this study are listed below. The longer of deposition day, the charge and discharge current was increased. It is considered that the reason is because there was water attack through the squared silica surface. The longer of deposition day, the absorption rate of all specimens was increased. It found that the absorption rate reached saturated state after 100 days. The higher frequency and the longer of deposition day, the $tan{\delta}$ was decreased. Also, It found that the $tan{\delta}$ and electrostatic capacity of the specimen which is mixed with squared filler are greater.

• 한국포장학회지
• /
• 제22권1호
• /
• pp.15-23
• /
• 2016

Gelatin soft capsules, manufactured by the press through package(PTP) process, are widely used in the production of multivitamin dietary supplements and other health functional foods. Gelatin capsules can prevent light and air from having a direct contact with the contents in the capsule, and the nutrients inside the capsules are preserved without any loss. In the present study, on the basis of the results on the safety of gelatin capsules. The parameters investigated included degradation of the capsules before their shelf life, capsule deformation, and changes in specific nutrients. Moisture and heat in the production and storage environments of the capsules caused the gelatin to swell and attach some of the inorganic salts in the vitamin contents. Nutritional component analysis showed that B1, B5, B9, and B12 contents were decreased, while mineral elemental analysis shown calcium, chloride, and zinc compound were found to be infused into the gelatin of the capsule shell.

• 생명과학회지
• /
• 제8권5호
• /
• pp.550-556
• /
• 1998

염소, 요오드, 담수처리에 의한 바이러스 병원성 약화 시험결과, 염소 5 ppm이상에서, 담수 50% 이상에서 살균효과를 나타내었으나 요오드는 효과가 없었다. Peptidoglycan, schzophyllan의 면역증강 효과를 시험한 결과, 각각 7일간 격 투여구와 2일간격 투여구에서 생존율이 대조군에 비해 높게 나타났다. 화학적, 효소적, 생물활균제를 투여하여 수질 및 저질 개선시험결과 화학적 개선제, Mg(OH)$_2$의 효과가 수질, pH, 강열감량 부분에서 효과가 가장 컸으며, 특이하게 효소적 개선제는 총 황화물의 농도를 약간 높이는 것으로 나타났다.

• 상하수도학회지
• /
• 제20권4호
• /
• pp.637-643
• /
• 2006

The bench-scale chlorine exposure study was performed to investigate the effect of pretreatment by free chlorine and monochloramine ($NH_2Cl$) on the performance of RO membranes made of polyamide (PA). Feed monochloramination at 2mg/L did not cause significant productivity loss compared to free chlorine. However, metal coagulants reacted with monochloramine, the PA membrane suffered from a gradual loss of membrane integrity by chlorine oxidation, which was characterized as a decrease in salt rejection. Especially, RO membranes exposed to alum coagulants with monochloramine revealed the salt rejection lower than those exposed to iron coagulants. XPS membrane surface analysis demonstrated that the chlorine uptake on the membrane surface increased and carbon peaks were shifted significantly when exposed to alum coagulants with monochloramine.

• 상하수도학회지
• /
• 제23권4호
• /
• pp.407-416
• /
• 2009

The objective of this study was to evaluate the variation of physical properties and adsorption capacity after regeneration of Granular Activated Carbon (GAC). It was found that the loss rate of regenerated carbon was related to the usage time of GAC. The correlations between iodide number and loss rate also determined. Effective size and uniformity coefficient for regenerated GAC were within a similar range compared to virgin GAC. This result indicated that the function as media is recovered. Although iodide number and specific surface area for regenerated GAC were not completely recovered compared to that of virgin GAC, cumulative pore volumes of regenerated GAC were increased. Removal efficiency of organic matter in regenerated GAC was resulted the same or slightly higher than that of virgin GAC. This result indicates that the number of mesopore responsible for removal of organic matter was increased after regeneration.

• 한국염색가공학회지
• /
• 제9권2호
• /
• pp.50-56
• /
• 1997

Poly(ethylene terephthalate) (PET) has been etched by sputtering in the presence of argon gas and the resulting surface modifications investigated via weight loss, time of water permeation, half value period, scanning electron microscope(SEM) and color difference measurements. According to increasing sputter etching time, weight loss increased, the time of water permeation and half value period of the sputter etched PET fabrics decreased. Color depth of fabrics increased by increasing sputter etching time. We investigated the fabric surface modification by SEM. Many microcraters on the fabric surface formed by the sputter etching resulted in increase of surface area of the fabric and wettability.

• 유체기계공업학회:학술대회논문집
• /
• 유체기계공업학회 2004년도 유체기계 연구개발 발표회 논문집
• /
• pp.43-48
• /
• 2004

A screw-type centrifugal pump was manufactured to carry solids primarily and its impeller has a wide flow passage. However, the effect of flow passage shape on delay of the choke due to entrained air has not been clarified yet. Moreover, because its impeller has a particular shape, only few studies have tried to clarify the pump performance and details of internal flow pattern of that pump. For that reason, we carried out the pump performance experiment under air-water two-phase flow condition with different impeller tip clearances, pump rotational speeds and void fractions by using a small screw-type centrifugal pump designed to acquire basic data. In a general centrifugal pump, it was reported that loss of pump head from single-phase flow to the choke due to air entrainment new the best efficiency point was large. However, the loss near the best efficient point in a screw-type centrifugal pump became less than that in a general centrifugal pump.