• Transactions on Electrical and Electronic Materials
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• 제11권4호
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• pp.174-177
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• 2010

We have developed an environment-friendly etching process, an alternative to the dichromic acid etching process, as a pretreatment of acrylonitrile-butadiene-styrene (ABS) plastic for electroless plating. In order to plate ABS plastic in an electroless way, there should be fine holes on the surface of the ABS plastic to enhance mechanically the adhesion strength between the plastic surface and the plate. To make these holes, the surface was coated uniformly with dispersed chemical foaming agents in a mixture of environmentally friendly dispersant and solvent by the methods of dipping or direct application. The solvent seeps into just below the surface and distributes the chemical foaming agents uniformly beneath the surface. After drying off the surface, the surface was heated at a temperature well below the glass transition temperature of ABS plastic. By pyrolysis, the chemical foaming agents made fine holes on the surface. In order to discover optimum conditions for the formation of fine holes, the mixing ratio of the solvent, the dispersant and the chemical foaming agent were controlled. After the etching process, the surface was plated with nickel. We tested the adhesion strength between the ABS plastic and nickel plate by the cross-cutting method. The surface morphologies of the ABS plastic before and after the etching process were observed by means of a scanning electron microscope.

• Journal of Microbiology and Biotechnology
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• 제22권12호
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• pp.1681-1691
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• 2012

This work was conducted to evaluate the effect of dilute sodium hydroxide (NaOH) on barley straw at boiling temperature and fractionation of its biomass components into lignin, hemicellulose, and reducing sugars. To this end, various concentrations of NaOH (0.5% to 2%) were applied for pretreatment of barley straw at $105^{\circ}C$ for 10 min. Scanning electron microscopy (SEM), atomic force microscopy (AFM), and Fourier transform infrared (FTIR) spectroscopy studies revealed that 2% NaOH-pretreated barley straw exposed cellulose fibers on which surface granules were abolished due to comprehensive removal of lignin and hemicellulose. The X-ray diffractometer (XRD) result showed that the crystalline index was increased with increased concentration of NaOH and found a maximum 71.5% for 2% NaOH-pretreated sample. The maximum removal of lignin and hemicellulose was 84.8% and 79.5% from 2% NaOH-pretreated liquor, respectively. Reducing sugar yield was 86.5% from 2% NaOH-pretreated sample using an enzyme dose containing 20 FPU of cellulase, 40 IU of ${\beta}$-glucosidase, and 4 FXU of xylanase/g substrate. The results of this study suggest that it is possible to produce the bioethanol precursor from barley straw using 2% NaOH at boiling temperature.

• 한국식품저장유통학회지
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• 제13권2호
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• pp.168-173
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• 2006

자몽종자추출물처리와 포장재에 따라 반건시 곶감의 품질 변화를 알아보고자 하였다. 자몽종자추출물에 반건시 곶감을 침지한 후 대조구(무포장), LDPE(low density polyethylene) 필름 포장구와 적층 필름 포장구 (Nylon/LDPE)로 각각 포장하여 $15^{\circ}C$에서 $60{\sim}100$일간 저장한 결과 다른 포장구보다 적층 필름 포장구(Nylon/LDPE)가 중량변화에서는 86%, 곰팡이 발생율은 60%, 갈변도는 50% 이상 낮게 나타났다. 자몽종자추출물(GFSE) 처리와 대조구의 분석실험에서 유의적 차이는 보이지 않았으나 자몽종자추출물 처리시에 반건시 곶감의 표면색도에서는 색변화 억제에 효과를 보였다.

• KSBB Journal
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• 제14권3호
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• pp.358-364
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• 1999

참나무의 전처리에 과산화수소가 미치는 영향을 조사하였다. 반응온도는 $170^{\circ}C$이고 전처리에 사용된 반응용액은 암모니아, 황산 그리고 순수 물이었다.10% 암모니아용액을 사용한 경우 산을 사용하는 경우에 비해 리그닌 제거율은 55%로 상당히 높았지만 헤미셀룰로오스 회수율은 26%로 상당히 낮았다. 그래서 헤미셀룰로오스 회수율을 높이기 위해 암모니아 용액에 산화제인 과산화수소를 첨가하여 반응시켰는데 과산화수소 첨가량의 증가에 따라 리그닌 제거율과 헤미셀룰로오스 회수율의 증가는 크지 않았다. 그리고 과산화수소 첨가량의 증가에 따라 액상으로 용해된 당의 분해가 증가하여 전체 헤미셀룰로오스와 셀룰로오스의 물질수지에 문제가 있었다. 반응기에 주입된 과산화수소는 주로 반응기의 전반부에 충진된 기질과 반응하는 것으로 나타났다. 헤미셀룰로오스 회수율을 높이기 위해서는 알카리용액보다 산성용액에서 기질을 전처리하는 것이 필요하였고 산보다는 물을 사용하였을 때 과산화수소의 효과가 더 컸다.

• 신재생에너지
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• 제6권4호
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• pp.6-14
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• 2010

Pretreatment of cellulosic biomass is necessary before enzymatic saccharification and fermentation. Extrusion is a well established process in food industries and it can be used as a physicochemical treatment method for cellulosic biomass. Aqueous ammonia soaking treatment at mild temperatures ranging from 60 to $80^{\circ}C$ for longer reaction times has been used to preserve most of the cellulose and hemicellulose in the biomass. The objective of this study was to evaluate the effect of extrusion treatment on aqueous ammonia soaking method. Extrusion was performed with miscanthus sample conditioned to 2mm of particle size and 20% of moisture content at $200^{\circ}C$ of barrel temperature and 175rpm of screw speed. And then aqueous ammonia soaking was performed with 15%(w/w) ammonia solution at $60^{\circ}C$ for 1, 2, 4, 8, 12 hours on the extruded and raw miscanthus samples respectively. In the combined extrusion-soaking treatment, most compositions removal occurred within 1~2 hours and on a basis of 1 hour soaking treatment values, cellulose was recovered about 85% and other compositions, including hemicellulose, are removed about 50% from extruded miscanthus sample. The combined extrusion-soaking treated and soaking only treated samples were subjected to enzymatic hydrolysis using cellulase and ${\beta}$-glucosidase. The enzymatic digestibility value of combined extrusion-2 hours soaking treated sample was comparable to 12 hours soaking only treated sample. It means that extrusion treatment can shorten the conventional long reaction time of aqueous ammonia soaking. The findings suggest that the combination of extrusion and soaking is a promising pretreatment method to solve both problems for no lignin removal of extrusion and long reaction time of aqueous ammonia soaking.

• The Korean Journal of Pain
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• 제2권2호
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• pp.145-154
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• 1989

Pain is a common and important clinical symptom, and treatments aimed at relieving pain have a central position in medical practice. Recently Transcutaneous Electrical Nerve Stimulation (TENS) has been effectively used to control acute and chronic conditions that produce pain. But the mechanism of analgesia resulting from TENS remains obscure. In order to investigate the analgesic effect of TENS and it's action mechanism, TENS was applied in 40 rabbits with different frequencies, low frequency (2Hz) and high frequency (100Hz), for 20 minutes. And the pain threshold was measured by the temperature before and after stimulation, and an attempt was made to antagonize the stimulation effect with naloxone pretreatment (0.4 mg/kg) The results are as follows: 1) Both low frequency and high frequency TENS resulted in increasing the pain threshold significantly (Both p<0.01). 2) Naloxone pretreatment could antagonize the effect of increasing the pain threshold with low frequency TENS significantly (p<0.01), but not with high frequency TENS. Plasma beta-endorphin was measured by radioimmunoassay using an Beta-Endorphin Kit (Immunonuclear Corporation, Stillwater, Minnesota, USA) and Automatic Gamma Scintillation Counter (Micromedic System 4/2000) before and after stimulation. An attempt was made to reverse the stimulation effect with naloxone pretreatment (0.4 mg/kg). The results are as follows: 1) Low frequency TENS resulted in increasing the level of plasma beta.endorphin significantly (p<0.01), but high frequency TENS did not. 2) Naloxone pretreatment could reverse the effect of increasing the plasma beta-endorphin level with low frequency TENS significantly (p<0.01).

• 한국재료학회지
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• 제26권3호
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• pp.109-116
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• 2016

To achieve the fabrication of high-quality Ag-coated Cu particles through a wet chemical process, we reported herein pretreatment conditions using an ammonium-based mixed solvent for the removal of a $Cu_2O$ layer on Cu particles that were oxidized in air for 1 hr at $200^{\circ}C$ or for 3 days at room temperature. Furthermore, we discussed the results of post-Ag plating with respect to removal level of the oxide layer. X-ray diffraction results revealed that the removal rate of the oxide layer is directly proportional to the concentration of the pretreatment solvent. With the results of Auger electron spectroscopy using oxidized Cu plates, the concentrations required to completely remove 50-nm-thick and 2-nm-thick oxides within 5 min were determined to be X2.5 and X0.13. However, the optimal concentrations in an actual Ag plating process using Cu powder increased to X0.4 and X0.5, respectively, because the oxidation in powder may be accelerated and the complete removal of oxide should be tuned to the thickest oxide layer among all the particles. Back-scattered electron images showed the formation of pure fine Ag particles instead of a uniform and smooth Ag coating in the Ag plating performed after incomplete removal of the oxide layer, indicating that the remaining oxide layer obstructs heterogeneous nucleation and plating by reduced Ag atoms.

• 분석과학
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• 제22권2호
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• pp.136-140
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• 2009

AMS (Accelerator Mass Spectrometry)를 이용한 방사성 탄소연대측정법으로 퇴적물 및 토양시료를 측정하기 위한 화학적 전처리법의 유기물 회수율을 개선하기 위하여, 초음파를 이용한 방법을 개발하였다. 일반적으로 널리 쓰이는 부식산 전처리법 중 단계 마다 사용되는 스터링법을 대신하여, 초음파 (ultrasonic)를 사용하고 초음파 출력, 반응 온도, 반응 시간 등 실험조건을 결정하였다. 유기물 함유량이 적어 연대측정이 불가능했던 시료에 대한 탄소 회수율이 6배 향상되어 다량의 시료를 얻기 힘든 연대측정분야에서는 매우 중요한 개선이 이루어졌다. 또한 동일 시료에 대해 초음파법과 스터링법으로 처리한 시료의 연대측정결과를 비교하여 초음파법이 회수율 향상 이외에는 연대측정결과에 영향을 미치지 않음을 확인하여 실용성이 있음을 증명하였다.

• Journal of Photoscience
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• 제9권2호
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• pp.59-62
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• 2002

In chilling-sensitive plants, the donor side of Photosystem II is inhibited by the chilling treatment in the dark, while the acceptor side of Photosystem I is inhibited by the chilling under the moderate light. Since the addition of inhibitors of electron transfer from Photosystem II protects Photosystem I from chilling induced photoinhibition of Photosystem I, inhibition or down-regulation of Photosystem II activity in vivo may also protect Photosystem I from photoinhibition. It was revealed that dark-chilling pretreatment actually protected Photosystem I from photoinhibition. The results imply that down-regulation of Photosystem II under stress conditions may have a role to protect Photosystem I from photoinhibition.

• Corrosion Science and Technology
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• 제12권5호
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• pp.215-219
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• 2013

Aluminum alloy(3003) can be dissolved during hydration process with hot tap water. In order to increase the stability of aluminum alloy, it was pretreated with anodization and phosphoric acid before hydration process. The effect of pretreatment on the surface property changes was analyzed with X-ray Photoelectron Spectroscopy (XPS) and Inductively Coupled Plasma-Optical Emission Spectrometer (ICP-OES) and their results supported that the increase of hydroxyl group (-OH) on the surface formed during anodization and phosphorous acid treatment prevented the dissolution of aluminum alloy during hydration process at high temperature.