• Corrosion Science and Technology
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• v.10 no.1
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• pp.37-42
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• 2011

Aluminum was electrochemically etched in acid solution and the surface area was magnified by the formation of etch pits. Etched aluminum was covered with a compact and dense dielectric oxide film by anodization and applied to the aluminum electrolytic capacitor electrode. Capacitance of aluminum electrolytic capacitor is closely related with surface area, which depends on size and number of etch pits. Size of etch pits need to be controlled because inside of the pits can be buried by the formation of dielectric oxide film. In this work, the effect of ultrasound pretreatment on the aluminum etch pit formation and capacitance were investigated. Additionally, the relationship between the second etching effect on pit size and capacitance was studied.

• Journal of Hydrogen and New Energy
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• v.21 no.6
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• pp.580-586
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• 2010

Acid and alkali pretreatments were applied to tofu processing waste (TPW) to increase the solubility of ingredients in TPW. Pretreatment at 1.0% of HCl and 2.5% of NaOH condition resulted in the increase of SCOD concentration from 3.2 g COD/L to 27 g COD/L and 33 g COD/L, respectively. The acid and alkali-pretreated TPW was studied for its fermentative $H_2$ production capacity in batch mode using a thermophillic mixed culture. Alkali pretreatment on presence of 2.5% NaOH exhibited more soluble portion released compared to acid pretreatment using HCl, however the $H_2$ production from acid pretreated TPW was better than alkali-pretreated TPW probably due to the sodium inhibition on microbial activity. In addition, sewage sludge was externally added to the acid-pretreated (1.0% HCl) TPW by 20% (on volume basis). Average H2 production rate was increased from 31 to 78 ml/L-broth/hr, and it was attributed to the high buffer capacity and abundant nutrients especially divalent cation in sewage sludge.

• KSBB Journal
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• v.20 no.4
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• pp.317-322
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• 2005

Various recovery methods were investigated to maximize hemicellulose recovery from lignocellulosic material hydrolyzed by pure water. The pretreatment conditions of water hydrolysis were $170\~180^{\circ}C$ and 1 hour of reaction time. The percentage of hemicellulose solubilized increased as the temperature increased from 170 to $180^{\circ}C$. However, significant decomposition of sugar was observed at temperature of $180^{\circ}C$. From the results of water hydrolysis, the total amount of glucan in solid residue and liquid hydrolyzate was close to the total glucan in the original biomass. For hemicellulose, however, there was a significant difference between both contents. To prove this difference, various recovery methods were proposed. From the total sugar accountability (sugar in liquid + sugar in solid), it was confirmed that hemicellulose recovery in the hydrolyzate was increased if the product including both hydrolyzate and solid residue was physically stimulated by such as heating and ultrasound irradiation. This indicated that, in commercial scale processes that much bigger substrate sizes are used and a sufficient amount of leaching solvent can not be used after pretreatment, a significant amount of oligomers could be trapped in the solid matrix.

• Korean Journal of Plant Resources
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• v.21 no.4
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• pp.341-345
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• 2008

Two orchid species of Calanthe discolor Lindl. and C. discolor for. sieboldii (Decne.) Ohwi, which have different form flower color and size. They were crossed in mid April by artificial pollination, and the F1 hybrid seeds were collected mid October. Germination of seeds was investigated on pre-treatment of seeds and under the various environmental conditions. Germination was promoted by moisture absorption and ultrasonic treatment of seeds. Dark culture of F1 hybrid seeds enhanced germination and protocorm formation, and development into seedlings compared with light culture. Although, plant growth regulators such as NAA and BA had a slightly promotive effect on seed germination and protocorm growth, regenerated seeding were showed abnormal growth patterns. Regenerated F1 hybrid plantlets were successfully transferred to pot.

• Journal of the Korean Society of Food Science and Nutrition
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• v.41 no.7
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• pp.914-920
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• 2012

We investigated the effects of heat treatment and extraction method on the antioxidant activities of five medicinal plants: Cyperus rotundus, Eucommia ulmoides, Bupleurum falcatum, Achyranthes japonica Nakai, and Akebia quinata. Extraction was performed with only ultrasound, ultrasound after heating at $130^{\circ}C$ for 2 hours, and reflux extraction with distilled water. The phenolic contents of reflux extraction and ultrasound extraction after heating were higher than only ultrasound extraction, and ultrasound extraction after heating samples was higher than reflux extraction except for Eucommia ulmoides and Cyperus rotundus. Total flavonoid content was higher in reflux and ultrasound extraction after heating samples than only ultrasound extraction, except for Cyperus rotundus. ABTS radical scavenging activity was higher in reflux extraction and ultrasound extraction after heating a sample, than only ultrasound extraction. DPPH radical scavenging activity was higher in reflux extraction except for Achyranthes japonica Nakai and Akebia quinata. The reducing power of ultrasound extraction after heating was higher with Achyranthes japonica Nakai. From the results of this study, we can expect to increase the antioxidant activity of medicinal plant extracts by applying suitable extraction and pretreatment conditions on the type of medicinal plant.

• Korean Journal of Poultry Science
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• v.16 no.3
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• pp.157-167
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• 1989

Pretreatment of egg white and ion exchange resins was attempted to separate lysozyme from egg white efficiently. Apparent viscosity of egg white could be decreased to 3cp by homogenization for 30 minutes at 2, 000rpm and ultrasonication for 45 minutes. The result of testing adsorption capacity of lysozyme was as follows； CM-Sephadex C-25 ＞Duolite C464＞Amberlite C-50＞Dowex MSC-1＞Amberlite IRC-50＞Amberlite IRC-84. Although CM-Sephadex C-25 showed highest adsorption capacity of lysozyme, egg white could not eluted easily. Duolite Cf64 was selected based on relatively high lysozyme adsorption and good egg white eluting property for separation of egg white lysozyme. Na$^{＋}$ form of Duolite C-464 was most effective on adsorption of Iysozyme. To separate lysozyme from egg white efficiently rinse buffer and eluting solution were selected 0.1M sodium phosphate buffer at pH 6.5 and 10% ammonium sulfate respectively. After separating lysozyme from egg white, foaming power of egg white was decreased to 85.3%. Color of egg white gel was not changed while hardness of egg white gel was decreased by 30% after separating lysozyme. However, elasticity of egg white gel was increased by 13% in lysozyme-separated egg white.

• Korean Chemical Engineering Research
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• v.47 no.2
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• pp.258-261
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• 2009

In this work, we the ettect on extraction amounts and general composition content of phytoestrogen genistein and formononetin extracted from Sophoraflavescens Aiton by various ultrasonic waves(35, 72, and 170 KHz) and extraction time(30, and 60 min) were compared using extraction solvent water 100%. The pretreatment step was composed of ultrasonic waves extraction, filtration, concentration, and membrane filtration. The extracted sample was analyzed by reversed-phase high performance liquid chromatography(RP-HPLC). And the mobile phase applied was linearly changed with A/B of 80/20~65/35 vol% for 60 min(A water/acetic acid, 99.9/0.1 vol%, B acetonitrile/acetic acid, 99.9/0.1 vol%). The experimental results, general composition carbohydrate(0.255 to 0.413%) excepts, other ingredients was confirmed almost similarly. Also, The highest yield of extraction amount 3.17g was obtained by ultrasonic waves with a frequency of 170 KHz and an extraction time of 60 min. This work offers would be useful for chemical and biological studies of natural plants and its products.

• Journal of Ginseng Research
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• v.24 no.2
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• pp.53-57
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• 2000

Chlamydospores were isolated from hyphae of Cylindrocanon destmctans by homogenization and/or ultrasonic treatment. Rate of the isolated chlamydospores by the homogenization with glass tissue grinder were 9.8% of all total chlamydospores formed in the culture of C. destructans. The length of mycelial fragments after the homogenization was about 400㎛ They were, however, formed in clusters of the chlamydospores and the mycelia The rate of the isolated chlamydospores from additional ultrasonic treatment after the homogenization of the mycelia were 74.3%. The length of mycelial fragments with the ultrasonic treatment was about 20 fm and chlamydospores seemed to be isolated from the mycelial mats and dispersed evenly in the culture. The numbers of chlamydospore in a catena were 1 to 8 cells after the homogenization on potato dextrose agar (PDA). Meanwhile the numbers of them after added ultrasonic treatment were 1 to 4 cells. Germination percentages of the isolated chlamydospores from the ultrasonic treatment were 46.8% after incubation of 2 days on PDA at 20。C and 60.7% after incubation of 13 days at 5。C, respectively. Germination rate of chlamydospores to the total chlamydospores produced by the ultrasonic treatment was 55.8%. However, it was increased to 74% when it was measured in the germinated catenae to the total catenae.

• Journal of Environmental Science International
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• v.16 no.2
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• pp.211-218
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• 2007

The objectives of this study have been carried out to investigate the solubilization of municipal sewage sludge by single and dual frequency ultrasonic pretreatment, and the methane production characteristics of pretreated sewage sludge by specific methanogenic activity test for sewage sludge reduction. The waste activated sludge was collected from thickened tank of Suyoung sewage treatment plant in Busan city, and its concentration was adjusted to 1.0% total solids. Ultrasonic frequency was varied 15, 20, 15+20 kHz, and acoustic density was used a maximum 176W/L. The dual frequency ultrasonic pretreatment was found to be more effective than single frequency ultrasonic in the solubilization rate and methane production. The $SCOD_{Cr}/TCOD_{Cr}$, rate were 15.2%, 13.9%, 17.0% with single frequency of 15 kH2, 20 kHz, dual frequency of 15+20 kHz, respectively. The application of dual frequency ultrasound for sewage sludge pretreatment can be interest for sewage treatment plants having problems in sludge treatment and disposal.

• Proceedings of the Korean Institute of Surface Engineering Conference
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• 2016.11a
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• pp.180-180
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• 2016

보론이 도핑된 $3{\times}3cm$ 크기의 p 형 다결정 실리콘 기판의 표면을 경면연마한 후, 다이아몬드 입자의 seeding을 위해 슬러리 중 다이아몬드 분말의 입도를 5 nm로 고정하고 초음파 전처리 공정을 진행한 후, 다이아몬드 박막을 증착하였다. 다이아몬드 증착은 Microwave Plasma Chemical Vapor Deposition 장비를 이용하였으며, 공정 조건은 초기 진공 $10{\times}10^{-3}Torr$, 공정 가스 비율 $Ar:CH_4=200:2$, 가스 유량 202 sccm, 공정압력 90 Torr, 마이크로웨이브 파워 600 W, 기판 온도 $600^{\circ}C$이었다. 기판에 DC bias 전압을 인가하는 것을 공정 변수로 하여 0, -50, -100, -150, -200 V로 변화시켜가며, 0.5, 1, 2, 4 h 동안 증착을 진행하였다. 주사전자현미경과 XRD, AFM, 접촉각 측정 장비를 이용하여 증착된 다이아몬드 입자와 막의 특성을 분석하였다. 각 bias 조건에서 초기에는 다이아몬드 입자가 형성되어 성장되었다가 시간이 증가될수록 연속적인 다이아몬드 막이 형성되었다. Table 1은 각 bias 조건에서 증착 시간을 4 h까지 변화시키면서 얻은 다이아몬드 입자 또는 박막의 높이(두께)를 나타낸 것이다. 2 h까지의 공정 초기에는 bias 조건의 영향을 파악하기 어려운데, 이는 bias에 의한 과도한 이온포격으로 입자가 박막으로의 성장에 저해를 받는 것으로 사료된다. 증착시간이 4 h가 경과하면서 -150 V 조건에서 가장 두꺼운 막이 성장되었다. 이는 기판 표면을 덮은 다이아몬드 박막 위에서 이차 핵생성이 bias에 의해 촉진되기 때문으로 해석된다. -200 V의 조건에서는 오히려 막의 성장이 더 느렸는데, 이는 Fig. 1에 보이듯이 과도한 이온포격으로 Si/diamond 계면에서 기공이 형성된 것과 연관이 있는 것으로 보인다.