Dry etching of polydimethylsiloxane using microwave plasma

Hwang, Sung Jin,Oh, Dong Joon,Jung, Phill Gu,Lee, Sang Min,Go, Jeung Sang,Kim, Joon-Ho,Hwang, Kyu-Youn,Ko, Jong Soo IOP 2009 JOURNAL OF MICROMECHANICS AND MICROENGINEERING - Vol.19 No.9

<P>This paper presents a new polydimethylsiloxane (PDMS) dry-etching method that uses microwave plasma. The applicability of the method for fabricating microstructures and removing residual PDMS is also verified. The etch rate of PDMS was dominantly influenced by the gas flux ratio of CF<SUB>4</SUB>/O<SUB>2</SUB> and the microwave power. While the PDMS etch rate increased as the flux ratio of CF<SUB>4</SUB> was increased, the etch rate decreased as the flux ratio of O<SUB>2</SUB> was increased. The maximum etch rate of 4.31 µm min<SUP>−1</SUP> was achieved when mixing oxygen (O<SUB>2</SUB>) and tetrafluoromethane (CF<SUB>4</SUB>) at a 1:2 ratio at 800 W power. The PDMS etch rate almost linearly increased with the microwave power. The ratio of the vertical etch rate to the lateral etch rate was in a range of 1.14–1.64 and varied with the gas fluxes. In consideration of potential applications of the proposed PDMS etching method, array-type PDMS microwells and network-type microprotrusion structures were fabricated. The contact angle was dramatically increased from 104° (non-etched PDMS surface) to 148° (etched PDMS surface) and the surface was thereby modified to be superhydrophobic. In addition, a thin PDMS skin that blocked holes and PDMS residues affixed in nickel microstructures was successively removed.</P>

Microfluidic generation of Prussian blue-laden magnetic micro-adsorbents for cesium removal

Kang, Sung-Min,Rethinasabapathy, Muruganantham,Hwang, Seung Kuy,Lee, Go-Woon,Jang, Sung-Chan,Kwak, Cheol Hwan,Choe, Sang-Rak,Huh, Yun Suk Elsevier 2018 CHEMICAL ENGINEERING JOURNAL -LAUSANNE- Vol.341 No.-

<P><B>Abstract</B></P> <P>Here, we designed and synthesized a recoverable multifunctional adsorbent using a microfluidic reaction system and evaluated the removal performance of the smart adsorbent toward radioactive cesium as a model sample. Prussian blue-laden magnetic micro-adsorbents (PB-MNPs-MAs) with uniform morphology and monodispersity were generated via two-step sequential procedures using a glass capillary microfluidic system, followed by chemical co-precipitation with a high production rate. The cesium removal efficacy of the PB-MNPs-MAs was analyzed based on Langmuir and Freundlich isotherms by controlling adsorption parameters such as adsorbent size, initial cesium concentration, and contact time. The adsorption isotherm of the PB-MNPs-MAs was better fitted to the Langmuir model with a maximum cesium adsorption capacity of 58.73 mg g<SUP>−1</SUP>, which was 40% higher than that of macro-adsorbents in a dynamic magnetic field. This result can be attributed to their large specific area, which increased the kinetic rate of cesium adsorption and achieved saturation within 20 min. Additionally, the PB-MNPs-MAs were recovered from wastewater within 5 s under a static magnetic field, indicating their great potential for magnetic actuation. We believe that our PB-MNPs-MAs can encapsulate nano-functional adsorbents and prevent actuation, making them promising for environmental remediation and especially for removal of radionuclides.</P> <P><B>Highlights</B></P> <P> <UL> <LI> PB-MNPs-MAs were generated in microfluidic device using chemical co-precipitation. </LI> <LI> The prepared PB-MNPs-MAs are monodispersed with uniform morphology. </LI> <LI> PB-MNPs-MAs exhibited high Cs adsorption capacity (58.73 mg g<SUP>−1</SUP>). </LI> <LI> 100% recovery of PB-MNPs-MAs is possible under static magnetic field after Cs adsorption. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>

두개안면 섬유성 이형성증의 임상적 고찰

백롱민,오갑성,윤성호,백세민,황민호 大韓成形外科學會 1994 Archives of Plastic Surgery Vol.21 No.3

Fibrous dysplasia is a benign pathologic condition of bone and causes facial deformities as well as functional problems. We have managed 32 craniofacial fibrous dysplasia form March 1989 to December 1993. The most common age distribution of surgery was second decade(34%) and third decade(53%). In our patients, the desease process usually begins in childhood and progresses throughout puberty and adolescence. Treatment was aimed at preventing and correcting functional problems and achieving normal facial aesthetics. The reconstruction with other combined surgery, i.e., mandibular and maxillary osteotomies, reduction malar plasty, malar augmentation and orbit, nasal reconstruction with bone graft. Postoperative results were satisfactory in most cases. In some patients, repeated contouring(16%) surgery might produce less morbidity than a single massive resection. In evaluating the extent of the lesion, computerized tomography prooved to be a good diagnostic tool. Aethetically and functionally satisfactory surgical results were achieved by bone shaving in combination with reconstructive surgery.

서울의 Penicillinase Producing Neisseria Gonorrhoeae 발생빈도(1996)

김재홍,황동규,전재홍,김윤석,김중환,김용준,이창균,임동진,김현수,조창근,김경문,박상훈,전우형,김희성,이호정,차명수,김갑형,김형석,김석우,황지환,박병순,권오상,이민수,송기훈,성소영,이인섭,부태성 대한화학요법학회 1999 대한화학요법학회지 Vol.17 No.2

Background : In recent years, gonorrhea has been panedemic and remains one of the most commom STDs in the world, especially in developing countries. Objective & Methods: For the detection of a more effective therapeutic regimen and assessing the prevalence of PPNG, we have been trying to study the patients who have visited the VD Clinic of Choong-Ku Public Health Center in Seoul since 1980 by means of the chromogenic cephalosporin method. Results: In 1996, 139 strains of N. gonorrhoeae were isolated, among which 53(39.0%) were PPNG. Conclusion: Our results suggests that after a peak of 74.3% in 1993, the prevalence of PPNG in Seoul is gradually declining.

다양한 전처리 방법에 따른 양파의 이화학 및 영양학적 특성 분석

김광일 ( Kwang Il Kim ),황인국 ( In Guk Hwang ),유선미 ( Seon Mi Yu ),민상기 ( Sang Gi Min ),이상윤 ( Sang Yoon Lee ),최미정 ( Mi Jung Cho ) 한국산업식품공학회 2014 산업 식품공학 Vol.18 No.4

본 연구는 양파를 열처리 법 중에서 열수침지, 증기 및 볶음 처리에 따른 이화학적 및 영양학적 특성을 분석한 논문으로 열처리가 양파에 미치는 영향을 비교하고자 하였다. 상품을 구매할 때 1차적인 구매요소인 색도 및 경도측정과 추가적으로 pH와 조직관찰 결과로 최적조건 선정 후 영양학적 및 미생물 검사를 실시하였다. 열처리를 하지 않은 대조구에 비해 짧은 시간의 열처리에서는 더 진하고 선명한 색을 띠었으나, 장시간동안 처리한 열처리 시료는 색의 침착을 보였다. 원물과 처리구의 색은 열처리 시간에 따라 뚜렷한 차이를 나타냈고, 경도는 열처리 시간에 따라 짧은 시간에서는 분해효소의 불활성화로 유지 및 증가했지만, 3분 이상 처리하였을 때는 감소 경향을 나타냈고, 볶음처리는 짧은 시간으로도 물성이 연화됐다. 비타민은 열수 및 증기처리 1~2분 처리는 14% 정도 감소했지만 그 이상 처리 시에는 23~28% 범위로 큰 감소율을 보였으며, 유리당 및 유기산의 경우 열수침지 및 증기처리에서 손실을 보였지만, 볶음처리에서는 유지하거나 증가하는 경향을 나타냈다. 특히 유리당에서 열수침지 처리 시 높은 감소율을 나타냈다. Peroxidase activity 변화는 모든 처리구에서 75% 이상의 불활성화를 나타냈고, 특히 열수침지 및 증기 처리한 모든 시료에서 90% 이상의 불활성화를 나타내며 볶음처리보다 높은 불활성화율을 보였다. 미생물 측정한 결과 열수 침지 3분 이상 및 볶음처리 210초 이상 처리시 미생물 검출이 안됐으며, 증기처리 시료는 2분 처리만으로 사멸된 것을 관찰했다. 양파의 열처리 조건은 증기처리법으로 2분 동안 처리하는 것이 다른 처리법에서 처리한 시간들에 비해 최적으로 나타났다. 열처리 방법 별 각각의 최적 처리 시간을 가지고 있어, 높은 효율성이나 산업적으로 이용하려면 최적의 전처리 방법과 처리 시간을 산정하는 것이 중요하다. The pre-thermal treatment, or blanching, is an important process to minimize quality changes during main cooking or storage. In this study, three types of pre-thermal treatments were applied to onions to observe quality changes in their physicochemical, nutritional, and microbial properties. The washed and sliced onions were treated by hot-water immersion (100oC, 1~10 min), steaming (100oC, 1~10 min) and stir-frying with oil (180oC, 10~80 sec). The onions were cooled and wiped with gauze. The results showed that the total color difference of the treated sample increased to 18-23 units compared to that of the fresh control. The pH value of the onion was not significantly different with the exception of the stir-fried samples. The hardness of the onion tended to decrease depending on the treatment time. The micro-structures of onions treated by hot-water immersion and steaming were damaged above 2 min whereas stir-fried onions showed structural damage above 210 sec. In the analysis of the nutritional changes in the onion, the ascorbic acid content of the blanched treatments were lower than that of fresh onion and the free sugar contests showed a similar pattern excluding the stir-fried onions. In the organic acid content assay, the succinic acid content of the treated onion sample had significantly decreased compared with other organic acid contents (p<0.05). The peroxidase activities of the blanched treatments by hot-water immersion and steaming were inactivated by more than 92%, whereas only 76% inactivity was achieved by the stir-frying treatment. The mesophilic and psychrotrophic bacteria counts of the treated onion were not detected or decreased to near a 3-log scale, and yeast was detected only the sample treated by the stir-frying for 1 min. In particular, neither bacteria nor yeast counts in all onion samples by steam treatment were detected. Consequently, the results demonstrated that steam treatment for 2 min could be the optimal pre-thermal condition for onions to minimize the quality changes and increase safety.

열처리 방법에 따른 표고버섯의 이화학적 특성 및 영양학적 분석

이중규(Jung-Gyu Lee),김광일(Kwang-Il Kim),황인국(In-Guk Hwang),유선미(Seon-Mi Yoo),민상기(Sang-Gi Min),최미정(Mi-Jung Choi) 한국식품영양과학회 2015 한국식품영양과학회지 Vol.44 No.6

본 연구는 열수 침지, 증기 및 볶음 처리가 표고버섯에 미치는 이화학적 분석 및 영양성분 분석을 통해 최적 열처리 조건을 확립하고자 진행하였다. 소비자들이 상품을 평가할 때 1차적으로 먼저 관찰되는 색도와 경도를 측정하고 추가로 pH 측정 등으로 인한 이화학적 결과로 최적 조건을 선정한 뒤에 그 조건들에 대해서 영양학적 및 미생물 검사를 실시하였다. 색도는 열처리 시간이 길어질수록 색의 변색 정도가 증가하여 뚜렷한 차이를 나타내었다. pH 값은 열수 침지 처리의 경우 pH 증가량이 가장 높았으며 처리 시간이 지속될수록 pH가 증가하는 경향을 나타내었다. 다른 처리군의 경우 일정 시간의 처리 시간 이후에는 유의적인 차이를 보이지 않았다. 경도에서는 열수 침지와 볶음 처리의 경우 1분 이내의 열처리만으로도 경도가 감소하는 경향을 보였으며, 증기처리의 경우 1분 동안 경도가 유지되는 결과를 보였다. 일반성분 분석 결과는 증기 처리가 가장 원물에 가까운 결과를 나타냈다. 유기산 함량은 증기 처리에서 유기산 함량 감소율이 가장 낮았다. 또한 3분간 증기 처리를 하였을 때 미생물의 사멸 효과가 가장 높았다. 열수 침지 처리나 볶음 처리의 경우 전체적으로 증기 처리한 시료에 비해서 영양성분 함량이 줄어드는 경향을 나타냈다. 따라서 표고버섯을 증기 처리방법으로 열처리하는 것이 다른 열처리군에 비해서 최적으로 나타났다. 하지만 본 연구에서는 물리화학 및 영양학적 성분의 변화만을 분석하였기 때문에 실제 식품 산업이나 공정에 적용하기 위해서는 대용량 처리 시에 발생하는 문제들과 관련된 추가적인 연구를 필요로 할 것이다. In the food industry, thermal treatment is an important process for extending shelf-life of foods. However, heating process affects the physicochemical, nutritional, and microbial properties of foodstuff such as color, texture, pH, and proximate compositions. This study was conducted to select an optimal thermal treatment by observing physicochemical, nutritional, and microbial effects of shiitake mushrooms with different thermal treatment methods. Shiitake mushrooms were washed and sliced equally (5 cm×0.5 cm×0.5 cm) and then heat-treated by three methods. Samples were heated in 100°C boiling water, steamed for 10 min, or pan fried at 130°C for 4 min. Total color difference values showed significantly increasing tendency with treatment time. For pH values, boiling water-treated mushrooms showed increasing tendency according to increased thermal treatment. For the results of hardness, boiling water or pan frying-treated mushrooms showed reduced tendency within 1 min. In the case of steam-treated mushrooms, hardness values were maintained for 1 min. Organic acid contents of steam-treated sample showed the lowest value among treatments. For microbial counts, steam-treated samples for 3 min showed the lowest value. Consequently, the results of this study suggest that steam treatment could be the optimal thermal treatment to minimize quality loss of shiitake mushrooms.

포토레지스트를 이용한 다층 배선용 층간 절연막 제조

민성진,장인영,황성규,강안수 명지대학교 산업기술연구소 2006 産業技術硏究所論文集 Vol.25 No.-

Recently, Polyimides are one of the most widely used engineering plastics, particularly in aerospace, micro electronics, printed circuit, and high performance adhesive industries. In micro electronics industry, polyimides have been used for the application of inter layer dielectric materials (ILD) due to their low dielectric constant (k=3.0~3.5), thermal stability and excellent mechanical strength. To synthesize a new positive photosensitive polyimide, polyimide precursor (polyamic acid) was prepared by condensation polymerization of 3,3-4,4-benzophenone- tetracarboxylic anhydride (BTDA), pyromellitic dianhydride (PMDA) with 4,4-methylenebis[benzenamine] (MDA). And parts of carboxylic acid groups in poly(amic acid) were esterified with 2-diazo-1-naphthoquinone-5-sulfonyl chloride (NQD-ester) in presence of Na₂CO₃/dioxane followed by the chemical imidization of residual carboxylic acid units. The chemical structure of resulting polymer was characterized by ¹H NMR, FT-IR, and its thermal properties were examined by TGA and dielectric constant measured by impedance analyzer. From the results of TGA, PI(BTDA), PI(PMDA) and PI-NQD(PMDA) were stable up to 250 ℃ without thermal degration. But thermal stability of PI-NQD(PMDA) was superior to PI(BTDA) and PI(PMDA). We found that thermal stability of the prepared PI-NQD(PMDA) increased with sulfone group, hard segment at high temperatures. And dielectric properties of PI(BTDA), PI(PMI)A) and PI-NQD(PMDA) were increased according to backing temp and baking time. These suits was consistent with Maxwell equation. The polyimides were useful as positive working photodegradable polymer. Especially, the polyimide containing pyromellitic diimide moiety and sulfone group exhibited high thermal stability and low dielectric costants.

초임계 유체 멸균법의 작용기전과 멸균효과에 영향을 주는 인자에 대한 종설

박민호,황성주 충남대학교 약학대학 의약품개발연구소 2011 藥學論文集 Vol.26 No.-

퍼지 추론을 이용한 분류 벡터 양자화기의 성능 개선

황병하,김혜숙,서재성,박민식,곽훈성 全北大學校 1994 論文集 Vol.37 No.-

In Classified Vector Quantization(CVQ) for image coding, the block classification pondering the block characteristics will be the most important procedure if we consider system performance. But it does not take effect because classification of conventional CVQ followed act on a heuristic and statistics method. In order to solve the problem of conventional methods, i.e, for block classification effectively we propose a fuzzy inferencing algorithm to improve its performance. To do this, fuzzy rules must be generated in the first. Our rules are based on energy distribution in transform domain with respect to spatial variation. Ultimately fuzzy inferencing of this paper apply these fuzzy rules for efficient block classification on a input image. As a result of efficient classification, our proposed method shows that blocking effect is decreased and PSNR(peak to peak signal to noise ratio) is increased by about 1 ∼ 2 dB for 0.2 ∼ 0.6 bpp range, when the performance is compared with Aizawa's scheme^[9].

반하(Pinellia ternata)가 랫드의 수컷 생식기계에서 3β-HSD,SGP-2 및 AR 유전자 발현에 미치는 영향

연정민, 백인정, 김윤배, 노재섭, 황방연, 김순선, 조대현, 이범준, 윤영원, 남상윤 충북대학교 동물의학연구소 2005 Journal of Biomedical and Translational Research Vol.6 No.2

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