• 한국환경과학회지
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• 제23권1호
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• pp.97-104
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• 2014

The sludge flotation/thickening apparatus equipped a micro-bubble generating pump was used to investigate micro-bubble generating properties on operational parameters. We evaluated micro-bubble generating properties as results to be operated the apparatus by operational parameters which are pump discharge pressure, air/water ratio(A/W ratio), air flow rate, and water flow rate. Micro-bubble generating efficiencies in pumps without recycling flow and with 50% of recycling flow was found to be very efficient on optimum A/W ratio from 1.06 to 3.62% and optimum A/W ratio from 1.05 to 4.06%, respectively. In condition of 3.6% of A/W ratio, we showed that the apparatus could be generated 36,000 ppm of micro-bubble concentration to be optimum treatment efficiency in sludge thickening process.

• 복식
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• 제55권8호
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• pp.154-160
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• 2005

For the purpose of standardization and practicability of natural dyeing, the mordanting and dyeing properties of Puerariae Radix was studied. Appropriate extraction, dyeing and mordanting condition of Puerariae Radix were determined, and the effect of mordanting method on dye uptake and color fastness of dyed fabric was investigated. The maximum absorbance of Puerariae Radix solution was at 290nm and 301nm. The pH effect was stable in the color difference changes. The optimum temperature to extract Puerariae Radix was during 1 hour in loot. The effective dyeing temperature and time of silk were 80$\~$ 100$^{circ}C$, 1hour. The silk fabrics dyed with Puerariae Radix appeared yellow-brown. US value of dyeing fabrics was increased by Fe, and Cu mordant treatment. Mordanting treatment method affected color change of the dyed silk. In the case of Puerariae Radix light fastness of appeared more than 2-5 grades by mordant treatment. Perspiration fastness of appered more than 4 grades by Al, Sn, Cr mordant treatment. Fastness of abrasion and dry-cleaning appered more than 4-5 grades. These fastness improvement were generally effective for mordant treatment, specially Al, Sn, Cr.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2003년도 춘계학술대회 논문집 초전도 자성체 연구회
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• pp.73-76
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• 2003

Phase transformation of Bi-2223 tape during the final heat treatment has been investigated through the various duration time of heat treatment in a specially designed 3-step heat treatment. It was found that the phase assemblage in the sintering was determined by the sintering time and temperature. In this study, sintering time was changed to optimize the Bi-2223 phase assemblage, and acquire high critical current density. High critical current samples with Ic = 85 A and Je = 8.9 kA/$cm^2$ have been measured at 77K and self-field for 55-filament tapes sintered by optimum condition.

• 상하수도학회지
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• 제22권3호
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• pp.373-378
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• 2008

The pH & alkalinity adjustment method by lime and carbon dioxide($CO_2$) for corrosion control in water distribution system was investigated to determine the optimum operational condition in lime adding process in water treatment plant(WTP). The mixing time at dissolution tank and sedimentation time at saturator for maintaining optimal turbidity condition of lime supernatant were 60~75 minutes and 75~95 minutes, respectively. There was no difference according to $CO_2$ adding methods such as $CO_2$ saturated water or $CO_2$ gas. But, $CO_2$ saturated water could be convenience at WTP in terms of pH control and quantitative dosing. To minimize generation of calcium carbonate products, the short time interval between adding of lime and $CO_2$ is most important. The lime should be added below 32 mg/l for preventing pH rising and generation of calcium carbonate products at the heating condition.

• 대한의용생체공학회:의공학회지
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• 제11권2호
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• pp.295-304
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• 1990

In order to use for artificial dental tooth (dental crowens) , new glass-ceramics material has been studied. Its basic composition and the condition of heat treatment for crystalization, mechanical and chemical properties were investigated. Adding of the LAS system composition in the basic glass, time and temperature for crystalization were shortened. Fracture toughness (kic)of samples heat treated at 90$0^{\circ}C$ for 2 hours is 2.5-2.6MN/m3/2, the optimum condition of heat treatment for artificial tooth is A and B samples heating to 75$0^{\circ}C$ for 2 hours, raising to 90$0^{\circ}C$ and maintaining at 90$0^{\circ}C$ for 2 hours and C sample heating to 75$0^{\circ}C$ maintaining at 75$0^{\circ}C$ for 2 hours. In acid and'alkali solution, chemical durability is excellent.

• 한국약용작물학회지
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• 제4권2호
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• pp.163-171
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• 1996

Lycoris의 종자발아(種子發芽) 특성(特性)을 구명(究明)하고자 온도(溫度), 채종시기(採種時期)와 파종시기(播種時期), 파종용토(播種用土)과 용토(用土)의 수분량(水分量) 및 광선(光線)의 유무(有無)가 종자발아(種子發芽)에 미치는 영향(影響)을 조사(調査)한 결과(結果)는 다음과 같다. 1. 백양꽃과 개상사화(想思花)는 90% 이상 결실(結實)하였고 종자성숙(種子成熟)은 $9{\sim}10$월 상순(上旬)으로 나타났는데 60% 이상의 발아율(發芽率)을 얻는데는 6개월이 소요되었다. 2. 발아적온(發芽適溫)은 $25^{\circ}C$로 나타났고 변온처리(變溫處理)는 $20,\;25^{\circ}C$에서 효과적(效果的)이었다. 3. 채종적기(採種適期)는 9월(月) 20일(日)경이었고 파종시기(播種時期)는 채종(採種) 즉시 파종(播種)하는 것이 가장 좋았다. 4. 파종용토(播種用土)은 사양토가 가장 좋았고 용토(用土)의 수분량(水分量)은 용토(用土) 400mg당 PF 1. 9가 가장 적당하였다. 4. 종자발아(種子發芽)는 암조건(暗條件)이 명조건(明條件)보다 좋은 것으로 나타났다.

• 한국식품조리과학회지
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• 제14권1호
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• pp.44-49
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• 1998

Microwave oven을 이용한 취반 시 최적 취반조건을 설정하기 위하여 전자렌지의 출력 및 가열시간을 달리하여 취반한 밥의 관능적 특성을 조사하였다. 쌀 1cup(약 173 g)을 수세하여 290 ml 물을 넣고 1시간동안 침지시킨 후 전자렌지의 출력과 가열시간을 5단계로 조절하면서 취반하였다(1단계; 온도상승기, 2단계: 수분흡수기1, 3단계: 수분흡수기2, 4단계: 열 침투기, 5단계: 호화완료기). 예비실험에서 설정한 출력과 가열시간에 따른 실험조건 수는 1200treatments였으나 1차, 2차에 걸친 취반실험 결과로부터 32가지의 최적 취반조건을 선정하였다. 그 중에서 다시 다음 3가지를 전자렌지의 대표적 인 취반조건으로 제시할 수 있었다. 1) 출력(7) 5:00-출력(1) 5:00(2) 5:00-출력(2) 6:00-출력(7) 4:00 2) 출력(8) 4:25-출력(1) 5:00-출력(2) 5:00-출력(2)

• Journal of Welding and Joining
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• 제18권5호
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• pp.70-76
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• 2000

The effect of Post Weld Heat Treatment(PWHT) of RE36 steel for marine structure was investigated with parameters such as micro-vickers hardness, corrosion potential and corrosion current density of weld metal(WM), base metal(BM) and heat affected zone(HAZ), and both Al alloy anode generating current and Al alloy anode weight loss quantity etc. Hardness of post-weld heat treated BM, WM and HAZ is lower than that of As-welded condition of each region. However, hardness of HAZ was the highest among those three parts regardless of PWHT temperature and corrosion potential of WM was the highest among those three parts without regard to temperature and corrosion potential of WM was the highest among those three parts without regard to PWHT temperature. The amplitude of corrosion potential difference of each other three parts at PWHT temperature $550^{\circ}C$, $650^{\circ}C$ are smaller than that of three parts by As-welded condition and corrosion current density obtained by PWHT was also smaller than that of As-welded condition. Eventually, it was known that corrosion resistance was increased by PWHT. However both Al anode generating current and anode weight loss quantity were also decreased by PWHT compare to As-welded condition when RE36 steel is cathodically protected by Al anode. Therefore, it is suggested that the optimum PWHT temperature with increasing corrosion resistance and cathodic protection effect is $550^{\circ}C$.

• 현장농수산연구지
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• 제11권1호
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• pp.95-101
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• 2009

약용 및 관상식물로 개발가치가 있는 백리향의 종자발아 및 삽목조건 구명을 위한 몇 가지 실험결과는 아래와 같다. 종자발아는 20℃ 광 조건에서 89%의 발아율로 가장 좋았다. 적정 삽목시기는 5월20일이 94%의 발근율로 가장 양호했고, 삽목용토는 단용보다는 peatmoss(50%) + perlite(50%) 혼용처리에서 좋았으며 삽목전 삽수의 IBA 처리농도는 100mg/L 침지처리에서 96% 발근율을 나타내었다.

• 열처리공학회지
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• 제31권3호
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• pp.97-103
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• 2018

The objective of this study is to develop the mechanical properties of AlSiCu aluminum alloy by the two-step solution heat treatment. The microstructure of gravity casting specimen represents a typical dendrite structure having a secondary dendrite arm spacing (SDAS) of 40 mm. In addition to the Al matrix, a large amount of coarsen eutectic Si phase, $Al_2Cu$ intermetallic phase, and Fe-rich phases are generated. The eutectic Si phases are fragmented and globularized with solution heat treatment. Also, the $Al_2Cu$ intermetallic phase is resolutionized into the Al matrix. The $2^{nd}$ solution temperature at $525^{\circ}C$ might be a optimum condition for enhancement of mechanical properties of AlSiCu aluminum alloy.