• 한국식품과학회지
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• 제22권2호
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• pp.172-176
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• 1990

크릴에 과량 존재하는 불소를 감량시키고자 전기분해 반응에 의한 electrocondensation 방법을 이용하였다. Electrotocondensation 방법에 의한 크릴 불소의 감량정도는 불소이온의 존재형태 (이온 및 결합상태의 불소, 총불소)와 시료의 부위(육질, 키틴질, 건조크릴)에 따라 차이가 있는 것으로 나타났다. 전기분해 반응시간에 따른 불소의 감량곡선을 살펴보면, 반응초기에는 불소의 감량이 빠르게 진행되었으나 일정시간 이후부터는 서서히 감량되는 경향을 나타내어 전기분해반응 120분 후에는 반응전 초기 불소농도의 $30{\sim}70%$ 수준까지 감량시킬 수 있었다. 이상의 결과를 살펴볼 때, electrocondensation 방법으로 크릴에 과량 함유되어 있는 불소를 상당량 제거하였지만. 아직도 많은 양의 불소가 각 시료에 잔재하고 있어, 완전한 불소세거를 위해서는 보다 깊은 연구가 필요로 되는 것으로 생각되었다. 즉 Newman은 세포외 불소가 벼에 집적되는 과정에서 hydroxyl기와의 치환반응을 고찰하였고, Rehbein등은 크릴을 주 먹이사슬로 하는 남극어류의 대부분이 chitinase와 pretense등의 강한 효소활성으로 크릴을 소화하는 과정에서 불소가 유리되어 체외로 방출되는 것으로 고찰하고 있어, 불소의 이동기작 및 집적과정에 대한 깊은 연구와 더불어 electrocondensation 방법을 보다 효율적으로 이용할 수 있는 방안이 모색된다면 크릴의 불소문제는 완전히 해결될 수 있을 것으로 생각되었다.

• 한국표면공학회지
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• 제27권4호
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• pp.207-214
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• 1994

In consideration of global environmental protection and fuel saving, aluminum alloy sheets for auto body panels such as hood, fender etc., are expected one of the most promising materials for weight saving of cars. The chemical conversion coating is required to prevent the filiform corrosion occurring on painted aluminum. However the conventional process for the composited material mixed with aluminum and steel is complexs; aluminum part is chromated and assembled to the body, and then the steel body undergoes Zn phosphating. In order to overcome the low productivity due to the complex process and the environmental problem with a conventional process, a simultaneous zinc phosphating process for alsuminum and steel in an assembled condition is demanded. Newly developed phosphate solution has been investigated to characterize the phosphating behavior under various conditions. The optimum conditions of the phosphating solution for the application of the paint treatment derived as follows : about 0.3 for the ratio of Zn to $PO_4$, , 200~500 ppm for the concentration of fluoride ion, and 2.5~4.0 for pH. The concentration of dissolved aluminum ion must be kept below 2--ppm and suitable accelerator is found to be a mixture of 1g/$\ell$ $NO_2\;^-$, and 6g/$\ell$ $NO_3\;^-$.

• 한국공작기계학회논문집
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• 제17권1호
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• pp.1-6
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• 2008

There are some methods that have been used to manage a degasing process in recent years, such as an injection method that uses aluminum molten metal powder and chemicals supplier and input method that supplies argon and nitrogen, or chlorine gas by using a gas blow-tube. However, these methods show some problems, and it shows that it is a difficult process to handle, pollution due to producing a lot of toxic gases like chlorine and fluoride gas, irregular effects, and lowering work efficiency due to the excessive processing time. The problems that are the most fatal are the producing a lot of sludge due to the reaction of aluminum molten metal with chemicals, loss of metals, and decreasing the life of refractory materials. In order to solve these problems, this paper develops a technology that is related to aluminum continuous casting molten metal and monolithic degasing apparatus. A degasing apparatus developed in this study improved the existing methods and prevented environmental pollution with smokeless, odorless, and harmlessness by using a new method that applies argon and nitrogen gas in which the methods used in the West and Japan are eliminated. The method developed in this study decreases the molten metal processing and settling time compared to the existing methods and improves the workers' health, safety, and environment because there is no pollution in processes.

• 자원리싸이클링
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• 제6권1호
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• pp.11-16
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• 1997

국내에서 발생하는 석탄 비산회로부터 $H_2$$SO_4$과 $CaF_2$을 침출제로 사용하여 알루미늄을 추출하나느 연구를 수행하였다. $H_2$$SO_4$과 $CaF_2$를 반응시켜 비산회의 주성분인 mullite를 분해하는 HF를 생성하여 효과적인 알루미늄의 추출을 유도하였다. $H_2$$SO_4$과 $CaF_2$농도, 반응온도 및 반응시간 등의 실험변수가 알루미늄의 침출에 미치는 영향을 조사하였으며 광액농도 5%m $106^{\circ}C$에서 4M $H_2$SO$_4$와 0.5M $CaF_2$의 조건으로 10시간 침출하여 최고 97%의 알루미늄 추출율을 얻을 수 있었다.

• 대한환경공학회지
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• 제34권10호
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• pp.702-708
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• 2012

사불화탄소($CF_4$)는 반도체 제조공정에서 에칭과 화학기상증착(CVD)에서 사용되어온 가스이다. $CF_4$는 적외선을 강하게 흡수하고 대기 중 잔류시간이 길어서 지구온난화에 영향을 미치기 때문에 고효율의 분해가 필요하다. 또한 불화수소를 포함한 폐수는 지하수 오염의 원인이 된다. 과도한 불소를 포함한 물을 장기간 섭취는 치아와 뼈에 문제를 야기한다. 워터젯 플라즈마를 이용하여 $CF_4$를 분해 후 생성되는 부산물 중 HF에 의하여 폐수가 생성된다. 이 폐수를 알루미늄 전극을 사용한 전해응집을 이용하여 폐수 중 HF를 제거 할 수 있는 시스템을 개발하였다. 실험 변수로는 초기 pH 변화, 반응 시간 변화, 주입유량 변화, 전류 밀도 변화를 실험하였다. 변수 실험을 통하여 초기 pH는 3.5, 반응 시간은 10 min, 주입 유량은 10 mL/min, 전류 밀도는 $159A/m^2$일 때 HF 제거율은 최고 85%까지 도달하였다.

• Journal of Information Display
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• 제7권2호
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• pp.26-30
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• 2006

Insertion of a thin lithium fluoride (TLF) layer between an emitting layer (EML) and an electron transporting layer has resumed in the developement of a highly efficient and bright organic light-emitting diode (OLED). Comparing with the performance of the device as a function of position with the TLF layer in tris-(8-hydroxyquinoline) aluminum $(Alq_{3})$, we propose the optimal position for the TLF layer in the stacked structure. The fabricated OLED shows a luminance efficiency of more than 20 cd/A, a power efficiency of 12 Im/W (at 20 mA/$cm^{2}$), and a luminance of more than 22 000 cd/$m^{2}$ (at 100 mA/$cm^{2}$), respectively. We suggest that the enhanced performance of the OLED is probably attributed to the improvement of carrier balance to achieve a high level of recombination efficiency in an EML.

• Journal of Plant Biology
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• 제27권3호
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• pp.139-147
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• 1984

This in vitro study was employed to clarify the effects of several pollutants i.e. $SO_2$, fluoride, cadmium(Cd), aluminum(Al) and NaCl, on the organogenesis and growth responses of shoot-tip, stem and multiple-buds segments derived from hypocotyl or cotyledon culture of petunia seedlings. ${Na_2}{SO_3}$levels of more than 200$\mu{g}$/ml had significantly reduced organogenesis, growth, and chlorophyll content. The injuries caused by ${Na_2}{SO_3}$, concentration of more than 400$\mu{g}$/ml were alleviated by increasing hydrogenion concentration of medium, indicating some relationship between two factors. Organogenesis was not affected by the fluoride concentration up to 100ppm in the media, but the growth and chlorophyll content were greatly reduced by the fluoride. The effect of Cd depended on the explant sources used for the culture; 1.0ppm was effective for fresh weight increase in shoot tip culture, and 3.0ppm in stem segments culture. Organogenesis and growth were greatly reduced by more than 10.0 Cd treatment. Growth and formation of shoots were better with Na conc. of 0.3% compared to control, but those of roots were inhibited. Na concentration goes over 1.0%, organogenesis and subsequent growth were inhibited, and chlorophyll synthesis was drastically reduced. Chlorophyll content was increased on the medium supplemented with Al 50$\mu{g}$/ml compared to control. However the formation and growth of shoots were greatly inhibited with more than 400$\mu{g}$/ml and roots were not produced at all.

• 한국표면공학회지
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• 제28권5호
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• pp.289-299
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• 1995

The effects of phosphate coating have been studied on physical properties and corrosion resistance of painted aluminum alloy sheet for automobile body. The physical properties (surface roughness, paint adhesion, impact resistance and pencil hardness) and corrosion resistance(cyclic corrosion and filiform corrosion) were investigated. Phosphate coatings enhanced the physical properties of painted Al alloy sheet, especially paint adhesion after the 240hours water immersion test. Phosphate coating also markedly improved the resistance for cyclic corrosion and filiform corrosion of painted cold rolled steel and Zn-Ni plated steel sheet as well as painted Al alloy sheet. The corrosion resistance of painted Al sheets was varied with the concentration of free fluoride ion and metal additives like Ni and Mn in the phosphating bath. A maximum corrosion resistance was obtained at about 300ppm of fluoride ion and additives of Ni and Mn obviously increased the corrosion resistance of painted specimens.

• 대한화학회지
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• 제14권3호
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• pp.201-206
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• 1970

Furfuryl acetate was chlorinated in presence of acetic acid using carbontetrachloride as the solvent. When the chlorination proceeded at the low concentration of acetic acid, the formation of the tetrachloride was more efficient than that of higher concentration. The chlorination done in presence of various Lewis acids such as aluminum chloride, hydrogen fluoride, and borontrifluoride could not give high yield of tetrachloride, but trichloride. In case of borontrifluoride and hydrogen fluoride, the decomposition of the reaction mixture was apparent. The results were discussed in terms of the stability of furfuryl nucleus towards an electron acceptor and the convenient procedure of preparing trichloro furfuryl acetate was described.

• 한국연초학회지
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• 제23권2호
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• pp.141-148
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• 2001

Insecticidal effect or sulfuryl fluoride ($SO_2F_2$) to cigarette beetle, Lasiodema serricorne (F.), was studied in two different containers, one was 1m$^3$(without cardboard block) and the other was 0.5m$^3$(with cardboard block). Adults and larvae were transferred into a small metal can before placed in the containers. Each can was held for 8, 24, 48, 72, and 96 hours after $SO_2F_2$(10, 20, 30, and 40 g/$\ell$) treatment. All adults were killed in an 1m$^3$container. Larval mortality was 99 to 100% when the dosage of SO$_2$F$_2$was 10 and 20 g/$\ell$. Cardboard was attached between two 0.5m$^3$ containers ; one was fumigation area and the other was insect area. SO$_2$F$_2$ penetrated cardboard within 24 hours in most trials. $SO_2F_2$could affect all adults and larvae regardless of their susceptibility. All adults were killed at 8 hours in a 0.5m$^3$ container. But low mortality of larvae was recorded at 8 hours when small dosage was treated (30% in 10 g/$\ell$, 87.2% in 20 g/$\ell$). The mortality was increased as SO$_2$F$_2$ dosage increased. Six different metals (stainless, copper, brass, aluminum, iron, and zinc) were also tested to study metal corrosion and discoloration. No corrosion and discoloration was observed in most metals treated with $SO_2F_2$.