• 한국분말재료학회지
• /
• 제6권2호
• /
• pp.132-138
• /
• 1999

A new binder system and debinding process for low carbon residue in the injection molding of Nd(Fe, Co)B powder are investigated. In the injection molding of magnetic materials, it is demanded to reduce carbon residue which deteriorates their magnetic properties. The binder system developed is composed of polyethylene glycols (PEGs) and polypropylene (PP). PEG was selected as a major binder is component to be extracted in a molecular state by solvent extraction in ethanol, which step would leave no residue. PP was selected as a minor binder component to be subsequently removed by thermolysis which step would leave carbon residue. The behaviors of solvent extraction with the variations of PEG molecular weight, temperature, and time were examined. The dependency of residual carbon content on thermolysis atmosphere was also studied. Opened pore channels introduced in a green body by the solvent extraction and microstructures of the sintered magnets were observed using SEM.

• 마이크로전자및패키징학회지
• /
• 제28권2호
• /
• pp.45-50
• /
• 2021

Flip chip 제품의 난이도 증가에 따라 solder wetting 및 신뢰성 관점에서 강점을 갖는 flux 소재에 대한 관심이 높아지고 있다. 지용성 flux의 경우 별도의 세정 공정이 없기 때문에 공정 효율화 측면에서 유리하나, 리플로우 공정이후 반응을 마친 잔여물이 잔존하게 되는 경우 Cu migration 및 delamination을 발생시킬 수 있다. 본 연구에서는 저잔사 flux 구현을 위해 신규 resin에 적합한 solvent 및 activator를 변경 하였으며, package 환경에서 non-wet 및 신뢰성 개선 유무를 확인하였다. 저장 안정성 평가를 통해 신규 소재에 대한 안정성을 확보하였으며, boiling point가 상이한 solvent와 activator 2종 적용 및 activator 함량 증대를 통해 non-wet 미 발생 flux 소재를 확보하였다. 해당 소재에 대한 신뢰성 검증 이후 평면 분석 결과 flux residue 기인성 delamination 현상은 발견되지 않았으며, 이를 통해 저잔사 flux에 대한 최종 조성을 확보하였다.

• 에너지공학
• /
• 제2권1호
• /
• pp.68-74
• /
• 1993

본 연구에서는 감압잔사유의 활용을 극대화하는 것을 목적으로 초임계 용매 추출법을 이용하여 탈아스팔트오일을 추출하였다. 초임계 용매로 n-pentane을 사용하였으며 온도와 압력 변화에 따른 추출수율과 추출된 오일 중 금속성분 및 황성분 함량의 변화가 조사되었다. 탈아스팔트오일의 추출수율은 사용한 용매의 초임계 영역에서 밀도에 크게 좌우됨이 조사되었고 추출유의 금속성분 함량은 감압잔사유에 비하여 크게 제거되었으나, 황성분 제거율은 낮았다.

• Bulletin of the Korean Chemical Society
• /
• 제9권4호
• /
• pp.202-206
• /
• 1988

In order to investigate the oligomerization state of the plasma membrane proteolipid apoprotein purified from the bovine kidney, fluorescence polarization experiment was carried out in the two different solvent systems, i.e., water and organic solvent(chloroform-methanol). The molecular volumes of the proteins estimated from the Perrin equation, were to be 45,258$A^3$ and 17,608$A^3$ in water and organic solvent, respectively. These values indicate that a trimerization is possibly occurring in the aqueous environment. As an auxiliary experiment for the calculation of the molecular volume using Perrin equation, fluorescence quenching constants ($K_q$) with the quencher acrylamide and fluorescence lifetimes (${\tau}_F$) of the intrinsic fluorophore tryptophan residue were estimated in the two different solvent systems. $K_q$ in water was 18.21$M^{-1}$ and it was 46.24$M^{-1}$ in organic solvent. Fluorescence lifetimes of tryptophan residue were calculated to be 2.80 nsec. in water and 3.81 nsec. in organic solvent, respectively.

• Bulletin of the Korean Chemical Society
• /
• 제26권2호
• /
• pp.238-240
• /
• 2005

The enthalpies of transfer, ${\Delta}H_t{\Theta}$, of NaI from water to aqueous methanol, ethanol and isopropanol, iPrOH, systems are reported. These data have been analysed in terms of the new solvation theory. These data are considered in terms of the new developed solvation theory including variable ($\alpha$n + $\beta$N), the net effect of the solute on the solvent-solvent bonding, is positive if there is a net breaking or weakening of solvent-solvent bonds. The solvation parameters recovered from the analyses indicate that the net affect of NaI on solvent structure is a breaking of solvent-solvent bonds and that NaI is preferentially solvated by water in all aqueous alcohol systems considered. ($\alpha$n + $\beta$N) values increase with increasing in the size of the alcohol alkyl residue from methanol to iPrOH.

• 한국도로학회논문집
• /
• 제17권4호
• /
• pp.53-61
• /
• 2015

PURPOSES : The objective of this study is to evaluate the SDAR (solvent deasphaltene residue), which is obtained from the solvent deasphalting (SDA) process, as a pavement material. METHODS : The physical properties of the SDAR were evaluated based on its chemical composition, and asphalt mixtures with the SDAR were fabricated and used for the evaluation of mechanical properties. Firstly, the chemical composition of SARA (saturate, aromatic, resin and asphaltene) was analyzed using the TLC-FID (thin-layer chromatography-flame ionization detector). Moreover, the basic material properties of the asphalt binder with the SDAR were evaluated by the penetration test, softening point test, ductility test, and PG (performance grade) grade test. The rheological properties of the asphalt binder with the SDAR were evaluated by the dynamic shear modulus ($G^*$) obtained using the time-temperature superposition (TTS) principle. Secondly, the mechanical properties of the asphalt mixtures with the SDAR were evaluated. The compactibility was evaluated using the gyratory compacter. Moreover, the tensile strength ratio (TSR) was used for evaluating the moisture susceptibility of the asphalt mixtures (i.e., susceptibility to pothole damage). The dynamic modulus $E^*$, which is a fundamental property of the asphalt mixture, obtained at different temperatures and loading cycles, was used to evaluate the mechanical properties of the asphalt mixtures. RESULTS AND CONCLUSION : The SDAR shows stiffer and more brittle behavior than the conventional asphalt binder. As the application of the SDAR directly in the field may cause early failures, such as cracks on pavements, it should be applied with modifiers that can favorably modify the brittleness property of the SDAR. Therefore, if appropriate additives are applied on the SDAR, it can be used as a pavement material because of its low cost and strong resistance to rutting.

• Journal of Ginseng Research
• /
• 제20권1호
• /
• pp.60-64
• /
• 1996

In this study, we investigated the appropriate conditions to extract acidic polysaccharide and to prepare red ginseng extract being rich in acidic polysaccharide from red tail ginseng marc produced after manufacturing alcoholic extract from red tail ginseng. Amount of acidic polysaccharide in red tail ginseng marc was about 11%. The best condition for the extraction of acidic polysaccharide from the marc was using of 3~5 mg of $\alpha$-amylase/g residue/15 ml of distilled water, and the amount of acidic polysaccharide in water extract of the residue treated with $\alpha$-amylase was about 27%. So, it is possible to manufacture red ginseng extract being rich in acidic polysaccharide using water extract of red tail ginseng alcoholic residue as extraction solvent. From the above results, we suggest that red tail ginseng residue produced by manufacturing alcoholic extract of red tail ginseng has high potencies in the utilization of waste material.

• 공업화학
• /
• 제10권6호
• /
• pp.907-912
• /
• 1999

본 연구는 유기산염 및 알칼리 원료를 사용해 야채 및 과일등에 잔류되어 있는 농약 및 유성오염의 제거효과를 GC와 세정력 측정장치를 사용해 조사했다. 일반적으로 잔류농약 등의 유성 오염원을 제거하기 위해서는 합성세제, 유기용제 등의 여러 방법이 있지만 본 연구에서는 특별히 식품첨가물 원료만 사용했다. 알칼리 수용액상에서 trisodium citrate를 사용했을때 가장 우수한 결과를 나타냈는데, 기존의 화학 합성세제와 비교했을 때 우수한 농약제거력이 나타났다.

• 한국태양에너지학회 논문집
• /
• 제31권6호
• /
• pp.66-71
• /
• 2011

Various single solvents were tested to find the effective solvent for the extraction of algae oil from wet-form Chlorella minutissima. In the case of single solvents, their extractabilities for algae oil were increased with their polarity because the water in wet algae cell is to form a solvent shell around the lipids. Based on these results, the wet-form algae samples were treated with a polar alcohol solvent and then a nonpolar solvent was added in algae residue. In the algae oil extraction by ethanol/n-hexane, total lipid contents were 40-50% and composition of triglyceride in extracted oil was 46.50%. Considering solvent toxicity of conventional solvent mixture such as chloroform and methanol for algae oil extraction, the ethanol/n-hexane system was identified as the effective one for the oil extraction from wet-form Chlorella minutissima.

• 한국포장학회지
• /
• 제10권1호
• /
• pp.1-6
• /
• 2004

Amount of residual ink solvent on the packaging materials from Korea, Japan and Europe was measured and compared. The amount of packaging materials from Korea was much higher than that of Japan and Europe. To reduce the residual amounts of ink solvent, aging condition of printed packaging materials including aging time and temperature was modified and evaluated. Aging with high temperature and short time ($60^{\circ}C$ and 24 hours) was more effective for reduction of residual amount of ink solvent than that with low temperature and long time. To find out change of reduction pattern of residual amount of solvent according to plastic packaging material, several monolayer and multilayer packaging materials were selected. Among the monolayer packaging materials, the amount of EVOH and PET was lower than that of polyolefin plastic film including PE and PP. PP/EVOH/PET among the selected multilayer film showed the lowest amount of residual ink solvent on food packaging materials. Result of this research revealed that the residual amount of ink solvent can be reduced by proper selection of aging condition with and by appropriate application of mutilayer plastic film.