• Journal of Biosystems Engineering
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• 제30권6호통권113호
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• pp.333-339
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• 2005

The pesticide is raising public interest in the world, because it causes damage to an environmental pollution and the human health remaining agricultural products and an ecosystem, in spite of the advantages. Particularly, each country restricts the residual pesticide and induces observance about the safety and usage standard so that they can control the amount of pesticide used and defend the safety of agricultural products. The habitual practice for the analysis of the residual pesticide depends on GC (gas chromatography), HPLC (high performance liquid chromatography) and GC/MS (gas chromatography/mass spectroscopy), which triturate the fixed quantity of samples, abstract and purify as a suitable organic solvent. These methods have the highly efficient in aspects of sensitivity and accuracy. On the other hand, they need the high cost, time consuming, much effort, expensive equipment and the skillful management. Carbofuran is highly toxic by inhalation and ingestion and moderately toxic by dermal absorption. As with other carbamate compounds, it is metabolized in the liver and eventually excreted in the urine. The half-life of carbofuran on crops is about 4 days when applied to roots, and longer than 4 days if applied to the leaves. This research was conducted to develop immunoassay for detecting carbofuran residue quickly on the basis of surface plasmon resonance and to evaluate the measurement sensitivity. Gold chip used was CM5 spreaded dextran on the surface. An applied antibody to Immunoassay was GST (glutathione-s-transferase). The association and the dissociation time were 176 second and 215 second between GST and carbofuran. The total analysis time using surface plasmon resonance was 13 minutes including regeneration time, on the other hand HPLC and GC/MS was 2 hours usually. The minimum detection limit of a permissible amount for carbofuran in the country is 0.1 ppm. The immunoassay method using surface plasmon resonance was 0.002 ppm.

• Elastomers and Composites
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• 제53권2호
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• pp.39-47
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• 2018

Styrene-butadiene rubber (SBR) is widely used in tire treads due to its excellent abrasion resistance, braking performance, and reasonable cost. Depending on the polymerization method, SBR is classified into solution-polymerized SBR (SSBR) and emulsion-polymerized SBR (ESBR). ESBR is less expensive and environmentally friendlier than SSBR because it uses water as a solvent. A higher molecular weight is also easier to obtain in ESBR, which has advantages in mechanical properties and tire performance. In ESBR polymerization, a surfactant is added to create an emulsion system with a hydrophobic monomer in the water phase. However, some amount of surfactant remains in the ESBR during coagulation, making the polymer chains in micelles clump together. As a result, it is well-known that residual surfactant adversely affects the physical properties of silica-filled ESBR compounds. However, researches about the effect of residual surfactant on the physical properties of ESBR are lacking. Therefore, in this study we compared the effects of remaining surfactant in ESBR on the mechanical properties of silica-filled and carbon black-filled compounds. The crosslinking density and filler-rubber interaction are also analyzed by using the Flory-Rehner theory and Kraus equation. In addition, the effects of surfactant on the mechanical properties and crosslinking density are compared with the effects of TDAE oil (a conventional processing aid).

• Applied Biological Chemistry
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• 제46권4호
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• pp.305-310
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• 2003

Hydrophobic core가 변이된 유비퀴틴 단백질이 pH 2 용액에서 보이는 구조적인 특성을 여러 분광학적 방법으로 측정하였다. 낮은 pH값을 갖는 용액에서 이 변이 유비퀴틴의 intrinsic tryptophan fluorescence emission spectrum은 unfolded 상태보다 약간 blue shift되어 있고 또한 그 intensity도 상당히 낮게 나타났다. 이는 이 용액 조건에서 이 변이 유비퀴틴의 삼차구조가 약간 남아 있는 것을 의미한다. 같은 용액에서 이 변이 유비쥐틴의 far-UV circular dichroic spectrum은 native 상태나 unfolded 상태의 spectrum과 현저히 달랐으며 220 nm 에서의 molar ellipticity 값을 통하여 볼 때 pH 2인 용액에서 상당량의 이차구조를 지니고 있었다. 또한 같은 용액에서 이 변이 유비퀴틴은 hydrophobic dye인 8-anilinonaphthalene-1-sulfonic acid(ANS)외 fluorescence emission intensity를 증가시키고 fluorescence emission maximum이 짧은 파장에서 나타나게 하였다(blue shift). 이러한 현상은 pH 2 용액에서 이 변이 유비퀴틴의 hydrophobic core가 느슨하여져서 hydrophobic dye인 ANS가 결합할 수 있는 구조를 띠고 있음을 나타낸다. 이러한 분광학적인 관찰은 이 변이 유비귀틴이 pH 2인 용액에서 상당량의 이차구조를 지니고 있지만 hydrophobic core는 느슨하게 형성된 molten globule과 같은 형태를 지니고 있음을 나타낸다. 이 변이 유비퀴틴의 molten 히obule 형태는 단백질 폴딩 반응의 경로를 연구할 수 있는 좋은 모델이 될 수 있을 것으로 생각된다.

• 자원리싸이클링
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• 제15권5호
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• pp.26-32
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• 2006

LCD와 반도체 제조공정에서 발생하는 인산, 질산, 초산, Al, Mo 등이 혼재하고 있는 인산계 혼산폐액을 액정제조공정에서 사용할 수 있는 고순도 에칭액으로 재활용하기 위해서 용매추출법, 진공증발법, 확산투석법 및 이온교환법의 각각의 기술적 특성을 살린 혼합 처리공정을 이용하여 고순도 인산회수 기술을 확립하고 상용화 시스템을 개발하고자 하였다. 시험 결과 진공증발에 의해 질산과 초산을 100% 제거할 수 있었고, TOP를 이용한 용매추출에서도 추출 4단, 탈거 6단으로 완벽하게 제거할 수 있었다. 이온교환의 전단계로 적용한 확산투석에서 Al 97.5%, Mo 36.7% 제거할 수 있었고 이온교환공정에서 Al 및 Mo를 각각 1ppm이하로 정제할 수 있었다.

• Asian-Australasian Journal of Animal Sciences
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• 제19권12호
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• pp.1776-1783
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• 2006

Despite being a rich source of protein (28-34%), karanj (Pongamia glabra) cake is found to be bitter in taste and toxic in nature owing to the presence of flavonoid (karanjin), tannin and trypsin inhibitor, thereby restricting its safe inclusion in poultry rations. Feeding of karanj cake at higher levels (>10%) adversely affected the growth performance of poultry due to the presence of these toxic factors. Therefore, efforts were made to detoxify karanj cake by various physico-chemical methods such as dry heat, water washing, pressure cooking, alkali and acid treatments and microbiological treatment with Sacchraromyces cerevisiae (strain S-49). The level of residual karanjin in raw and variously processed cake was quantified by high performance liquid chromatography and tannin and trypsin inhibitor was quantified by titrametric and colorimetric methods, respectively. The karanjin, tannin and trypsin inhibitor levels in such solvent and expeller pressed karanj cake were 0.132, 3.766 and 6.550 and 0.324, 3.172 and 8.513%, respectively. Pressure-cooking of solvent extracted karanj cake (SKC) substantially reduced the karanjin content at a cake:water ratio of 1:0.5 with 30-minute cooking. Among chemical methods, 1.5% (w/w) NaOH was very effective in reducing the karanjin content. $Ca(OH)_2$ treatment was also equally effective in karanjin reduction, but at a higher concentration of 3.0% (w/w). A similar trend was noticed with respect to treatment of expeller pressed karanj cake (EKC). Pressure cooking of EKC was effective in reducing the karanjin level of the cake. Among chemical methods alkali treatment [2% (w/w) NaOH] substantially reduced the karanjin levels of the cake. Other methods such as water washing, dry heat, HCl, glacial acetic acid, urea-ammoniation, combined acid and alkali, and microbiological treatments marginally reduced the karanjin concentration of SKC and EKC. Treatment of both SKC and EKC with 1.5% and 2.0% NaOH (w/w) was the most effective method in reducing the tannin content. Among the various methods of detoxification, dry heat, pressure cooking and microbiological treatment with Saccharomyces cerevisiae were substantially effective in reducing the trypsin inhibitor activity in both SKC and EKC. Based on reduction in karanjin, in addition to tannin and trypsin inhibitor activity, detoxification of SKC with either 1.5% NaOH or 3% $Ca(OH)_2$, w/w) and with 2% NaOH were more effective. Despite the effectiveness of pressure cooking in reducing the karanjin content, it could not be recommended for detoxification because of the practical difficulties in adopting the technology as well as for economic considerations.

• 한국자원리싸이클링학회:학술대회논문집
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• 한국자원리싸이클링학회 2006년도 춘계임시총회 및 제27회 학술발표대회
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• pp.90-94
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• 2006

액정(LCD)과 반도체 제조공정에서 발생하는 인산, 질산, 초산, Al, Mo 등이 혼재하고 있는 인산계 혼산폐액을 액정제조공정에서 사용할 수 있는 고순도 에칭액으로 재활용하기 위해서 용매추출법, 진공 증발법, 확산투석법 및 이온교환법의 각각의 기술적 특성을 살린 혼합 처리공정을 이용하여 고순도 인산 회수 기술을 확립하고 상용화 시스템을 개발하고자 하였다. 시험 결과 진공증발에 의해 질산과 초산을 100% 제거할 수 있었고, TOP를 사용한 용매추출에서도 추출 4단, 탈거 6단, 상비 1/3으로 완벽하게 제거할 수 있었다. 이온교환의 전단계로 적용한 확산투석에서 Al 97%, Mo 75% 제거할 수 있었고 이온교환공정에서 Al 및 Mo를 각각 1ppm 이하로 정제할 수 있었다.

• 폴리머
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• 제31권2호
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• pp.168-176
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• 2007

라이소자임이 내포된 폴리감마글루탐산(PGA)의 서브-마이크론 크기의 미세입자를 압력, 온도, 노즐내경, 농도 등을 변화시켜가면서 초임계 반용매 침전법 (SAS)으로 제조하였다. SAS법의 전체적인 결과는 압력이 클수록, 온도가 낮을수록, 노즐 내경이 작을수록, 농도가 묽을수록 작은 입자가 얻어졌다. FT-IR로 분석한 결과, 본래 초기의 PGA:라이소자임:50 : 50의 조성비는 SAS 공정을 거치면서 최종 분말 입자 내에서는 33 : 67로 변화하였다. 이것은 PGA가 라이소자임보다 탄산가스/디메틸설폭사이드(DMSO) 혼합용매에 더 높은 용해도를 가지기 때문인 것으로 추측된다. 또 이러한 용해도 특성 때문에 생성 입자는 핵-껍질 구조를 갖고 있으며, 핵 부분은 라이소자임이 구성하는 것으로 여겨진다. 생성된 분말 입자 내에는 $7.8\times10^{-3}wt%$의 농도로 미량의 DMSO가 잔존하고 있음이 밝혀졌다.

• 자원리싸이클링
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• 제28권2호
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• pp.46-53
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• 2019

본 연구에서는 백금족 금속의 분리회수 가능성을 알아보기 위해 백금족 금속 혼합물로부터 이온성액체 기반의 용매에서 백금족 금속의 추출과 전해 환원거동을 조사하였다. 촉매조성인 10:1:0.5 M의 비로 $PdCl_2$, $PtCl_4$, $RhCl_3$가 용해되어 있는 혼합액으로부터 이온성액체인 $[C_4mim]PF_6$를 이용하여 백금(Pt)을 선택적으로 추출한 후 수계 전해액인 1 M $HNO_3$으로 역추출하고 -0.8 V (vs. Pt-QRE)의 전압과 금을 작동전극으로 사용하여 백금을 우선적으로 회수하였다. 잔류하는 팔라듐과 로듐은 $[C_4mim]Cl$ 용액으로 추출한 다음 비수계 전해법으로 환원회수하였다. 전극물질과 전압에 따른 두 금속의 환원거동을 조사하였으며, 작동전극을 탄소, 금과 STS304를 이용하여 각각 팔라듐과 로듐을 순차적으로 회수할 수 있었다.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2015년도 제49회 하계 정기학술대회 초록집
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• pp.236.2-236.2
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• 2015

The copper-zinc(Cu-Zn) nanofiber was prepared by electrospinning method. The Cu/PVP (polyvinylpyrrolidone) and Zn/PVP precursor solutions were prepared by dissolution of copper sulfate and zinc acetate in methanol, respectively. The PVP was used to control the viscosity of the precursor solutions. The optimized ratio for the Cu/PVP and Zn/PVP nanofibers was determined separately. Then the suitable ratio of the precursor solutions was applied for fabrication of Cu/Zn/PVP nanofiber. For the electrospinning method, the precursor solutions were filled in a syringe. The distance between metallic needle on the syringe and collector was fixed at 16 cm and the voltage was applied on the tip was 13.0 kV. And the as-spun nanofiber was heated at 353K for removal of residual solvent. Then the heated nanofibers were calcined at 973K to decompose PVP. The obtained Cu, Zn, and Cu-Zn nanofibers were investigated with X-ray photoelectron spectroscopy (XPS) for the chemical properties, scanning electron microscopy (SEM) for the morphologies, and X-ray diffraction (XRD) to characterize the crystallinity and phase of nanofibers.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2015년도 제49회 하계 정기학술대회 초록집
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• pp.224-224
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• 2015

Gel have enormous applicable region due to inherently high stretchability and bio-compatibility. Here, we fabricated highly stretchable electronic conductive organogels which have long-term stability in environment. By introducing a dialysis step which can incorporate conducting polymer, PEDOT, on the procedure of gel synthesis, residual ions inside the gel were removed. In addition, we replaced the water with organic solvent, EG, inside the gels which is high stability in air. Unlike conventional hydrogels, there are no ionic conduction occurred and electrochemically driven current was prevented during electrical voltage was applied. The fabricated organogels are hardly dried during air exposure, and only electrically conductive without any electrochemical reaction at even high voltage. In order to utilize as stretchable conductor, we demonstrated a LED array circuit using the conductive organogels as electrical interconnects. It was successfully operative even stretched up to 300% strain.