• Journal of Welding and Joining
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• 제16권6호
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• pp.77-85
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• 1998

Effects of non-cleaning and cleaning fluxes on the wetting properties and defects at flow soldered joints were investigated. Non-cleaning flux (R-type of 3.3% solid content) and cleaning flux (RMA-type of 15% solid content) were used. Wetting test was accomplished by wetting balance method with changing surface state of wetting specimen, CU. Sn-37%Pb solder was used for wetting test and flow soldering. As experimental results, the wetting time for vertical force from the surface tension being zero was mainly affected by surface state of the wetting specimen. Non-cleaning flux had a good wettability compared with cleaning flux. In case of non-cleaning flux, conveyor speed had a great affection to defects of bridge, icicle, and poor solder.

• 한국응용과학기술학회지
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• 제16권3호
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• pp.237-240
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• 1999

This study showed that the optimized cleaning process using non-aqueous cleaning solvents is adaptable in the industrial field for existing 1.1.1-TCE cleaning solvents which is an ozone depleting sustance. Alternative cleaning solvent system substituted for existing cleaning solvent against non-aqueous pollutants(cutting & flux oil), was evaluated for the cleaning efficiency using gravimetric analysis method and surface change of sample by Image analyzer. The results showed that alternative solvents and process had excellent cleaning efficiency.

• Journal of Biosystems Engineering
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• 제31권4호
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• pp.376-384
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• 2006

This study was conducted to perform for comparative analysis of the cleaning efficiency on 3 kinds of cleaning liquid state, 3 steps of cleaning temperature $(45^{\circ}C,\;60^{\circ}C,\;70^{\circ}C,\;)$ and 6 steps of cleaning time (2.5, 5, 7.5, 10, 12.5, 15 minute). 3 kinds of cleaning liquid state are the non fluidized bed, liquid fluidized bed and liquid/solid fluidized bed. UV spectrophotometer was used in estimation of cleaning efficiency, which it is experimental equipment using the absorptiometric analysis method. Cleaning efficiency by cleaning time was increase from 2.5 minutes to 15 minutes, liquid/siolid fluidized bed was indicated the highest cleaning efficiency among the 3 kinds of cleaning liquid state and $70^{\circ}C$ of cleaning temperature at liquid/solid fluidized bed was indicated the highest cleaning efficiency as 98% among the 3 steps of cleaning temperature.

• 청정기술
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• 제12권4호
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• pp.250-258
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• 2006

CFC-113과 1,1,1-trichloroethane 등과 같은 CFC 화합물은 화학적 안정성 및 열역학적 특성 등이 우수하고, 불연성이며, 부식성이 없는 화합물로 오랜 시간 동안 전 산업에 걸쳐 널리 사용 되어 왔다. 하지만, 1989년 지구 환경의 보호를 위해 이들의 생산과 사용을 규제하는 국제협약인 '오존층 파괴물질에 관한 몬트리올 의정서'가 체결되어 대체 세정제가 요구되고 있다. 본 연구에서는 세정 시스템을 변화시키지 않고 세정력이 우수하면서 환경 친화적이며 인체 유해도가 낮으며 부식성 물질을 발생 시키지 않는 비수계 세정제를 개발하고자 하였다. 이를 위하여 글리콜 에테르계의 용매와 파라핀계 탄화수소 물질을 일정 비율로 혼합, 배합하면서 실록산을 첨가하여 비수계 세정제를 배합 제조하였다. 그리고 이들 세정제의 물성과 세정성을 평가하여 대체 세정제로서의 가능성을 평가하였다. 배합세정제의 물성측정 결과 밀도와 표면장력이 낮아 오염물에 대한 침투력이 우수할 것으로 예상되었고 인화점과 증기압 측정값으로 세정제의 안전성을 평가할 수 있었다. 플럭스, 솔더 및 그리스에 대한 세정성능 측정결과 높은 세정성능을 보여주었고 피세정물의 표면에 잔류물이 생성되지 않았다. 결과적으로, 규제물질과 동등한 세정능력을 지니며 침투력이 우수하고 인체 유해도가 낮은 세정제를 개발할 수 있었다.

• 한국강구조학회 논문집
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• 제21권1호
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• pp.55-62
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• 2009

강교 제작에는 강재 표면의 이물질 제거와 피복방식재료의 부착성 증대를 위하여 블라스트 표면처리가 실시되고 있다. 블라스트 표면처리는 쇼트나 그릿 등의 연마재를 압축공기로 분사하여 강재 표면에 충격을 가하는 표면처리법으로, 블라스트 처리에 의해 표면형상이 개선되고 압축잔류응력이 도입되어 용접이음의 피로수명이 향상될 것으로 예상된다. 본 연구에서는 하중비전달형 십자필렛 용접이음의 피로실험을 실시하여, 블라스트 표면처리가 용접이음의 피로거동에 미치는 영향을 실험적으로 검토하였다. 피로실험에는 용접 후 무처리 시험편(용접 그대로), 용접 후 블라스트 표면처리 한 시험편과 블라스트 처리 후 열처리에 의해 잔류응력을 제거한 시험편의 합계 3종류의 용접시험편을 대상으로 하였다. 그 결과 블라스트 표면처리에 의해 용접지단부의 곡률반경은 약 29% 증가하였으며, 용접지단부의 인장잔류응력이 제거되고 압축잔류응력이 도입되었다. 그리고 블라스트 처리에 의해 피로수명과 피로한계가 증가하였다. 피로수명은 응력범위가 낮을수록 더 크게 증가하였고, 피로한계는 약 1.5배 증가하였다.

• 한국농공학회논문집
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• 제56권5호
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• pp.67-75
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• 2014

In this study, the large-scale hydraulic model test was performed to investigate the hydraulic characteristics for development of the non-power soil cleaning and keeping system at the dike gate. The outlet height, outflow number, outflow discharge, and outflow cycle were compared and analyzed. The non-power soil cleaning and keeping system was most effective at 11.2 mm in the outlet height. And then the mean outflow cycle was 1.09 sec, and the mean outflow discharge was $0.00164m^3/s$. The total outflow number increased gradually as the water level of a water tank increased, and the outlet height decreased. As a level of water tank decreased, the mean outflow cycle was lengthened, and the unit outflow discharge increased. This result showed this system was most effective. To remove the silty clay deposited in facilities, the methods of excavation, dredging, high pressure washing, etc have been applied to the tidal facilities such as land reclamation, a small size fishing port, and a harbor for maintenance. However, this is extremely cost-ineffective, whereas the non-power soil cleaning and keeping system will bring about an enormously positive economic effect. In addition, when the non-power soil cleaning and keeping system is applied to the dike gate of land reclamation, a thorough examination of the local tidal data and the careful system planning are required to prevent the disaster damage caused by flooding.

• 복식문화연구
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• 제11권6호
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• pp.956-966
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• 2003

The purpose of study is to find out a suitable cleaning method for excavated textiles of Jeon-ui Lee(1570∼1647). The textiles were excavated from her tomb in 1997, and her descendents put them in a box without any treatment and kept them in the warehouse since then. We used two kinds of silk as samples, non-dyed and dyed textile. The experiment was performed by 8 kinds of wet cleaning and dry cleaning methods, an ultrasonic cleaner was used in the wet cleaning, decane and perchloroethylene were used as solvents in the dry cleaning. The use of the ultrasonic cleaner in the wet cleaning method did not show any damage to the fibers of the textiles and it not only cleaned well but also was safe for the fugitive dyes. It resulted in more effective cleaning when the detergent was used together. Therefore, it is effective to use the ultrasonic cleaning on the delicate historical textiles and helpful to the operator's safety and environment.

• E2M - 전기 전자와 첨단 소재
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• 제12권10호
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• pp.34-38
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• 1999

• Restorative Dentistry and Endodontics
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• 제48권3호
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• pp.25.1-25.13
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• 2023

Objectives: The purpose of this study was to evaluate the influence of endodontic access cavities design on the removal of calcium hydroxide medication of the apical third of mandibular incisor root canal walls and dentinal tubules with different cleaning protocols: EDDY sonic activation, Er,Cr:YSGG laser-activated irrigation, or conventional irrigation with IrriFlex. Materials and Methods: Seventy-eight extracted human mandibular incisors were assigned to 6 experimental groups (n = 13) according to the endodontic access cavity and cleaning protocol for calcium hydroxide removal: traditional access cavity (TradAC)/EDDY; ultraconservative access cavity performed in the incisal edge (UltraAC.Inc)/EDDY; TradAC/Er,Cr:YSGG; UltraAC. Inc/Er,Cr:YSGG; TradAC/IrriFlex; or UltraAC.Inc/IrriFlex. Confocal laser scanning microscopy images were used to measure the non-penetration percentage, maximum residual calcium hydroxide penetration depth, and penetration area at 2 and 4 mm from the apex. Data were statistically analyzed using Shapiro-Wilk and WRS2 package for 2-way comparison of non-normally distributed parameters (depth of penetration, area of penetration, and percentage of non-penetration) according to cavity and cleaning protocol with the significance level set at 5%. Results: The effect of cavity and cleaning protocol interactions on penetration depth, penetration area and non-penetration percentage was not found statistically significant at 2 and 4 mm levels (p > 0.05). Conclusions: The present study demonstrated that TradAC or UltraAC.Inc preparations with different cleaning protocols in extracted mandibular incisors did not influence the remaining calcium hydroxide at 2 and 4 mm from the apex.

• 공업화학
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• 제16권4호
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• pp.533-541
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• 2005

2,2,2-trifluoroethanol (TFEA)과 hydrofluoroether (HFE)를 혼합하여 비수계 세정제를 제조하고 이들의 혼합비에 따른 물성과 세정성의 영향을 연구하였다. 또한 TFEA를 기초로 하고 비이온 계면활성제, 가용화제와 빌더를 첨가한 수계 세정제를 제조하고 이들의 세정능력을 비교하여 CFC-113, 1,1,1-TCE에 대한 대체 가능성을 평가하였다. 오염 물질로 수용성이거나 친수성, 지용성이거나 친유성인 각기 다른 플럭스, 절삭유, 그리스, 불소계 오일 등을 선정하고, 세정시간에 따른 오염물질의 중량변화를 비교하여 각 세정제의 세정능력을 비교함으로써 대체세정제로서의 TFEA를 기초로 한 세정제의 적용 가능성을 평가하였다. 그 결과 TFEA와 HFE를 주성분으로 하여 제조한 비수계 세정제는 플럭스와 불소계 오염물에 우수한 세정성을 보여주었지만 그리스 세정에서는 세정성이 떨어졌다. 이에 비하여 TFEA를 기초로 하고 비이온 계면활성제, 가용화제, 빌더 등을 첨가하여 제조한 수계세정제는 일정한 배합 조건에서 플럭스와 그리스 제거에 매우 효과적이었다. 따라서 TFEA를 기초로 한 수계 및 비수계 세정제는 특정 오염물질에 대하여 좋은 세정력을 보여 주어 CFC-113, 1,1,1,-TCE 등의 대체세정제로의 가능성을 보여주었다.