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>

Development of Simultaneous Analytical Method for ImidazolinoneHerbicides from Livestock using LC-MSMS

Hyo-Min Heo,Hyeong-WookJo,Kyu-Won Hwang,Jung-Hun Sun,Joon-Kwan Moon 한국농약과학회 2021 한국농약과학회 학술발표대회 논문집 Vol.2021 No.11

Simultaneous analytical method using LC/MSMS for imidazolinone herbicides from livestock (egg, milk, beef, pork and chicken) for monitoring was developed with QuEChERS preparation. Sample weighing (5g) in a 50mL conical tube, added 0.1 M potassium phosphate dibasic solution (5mL) was shaken for 10min. After 0.5mL 6 NHCl, 10mL acetonitrile were added, it was shaken for 10min. And QuEChERS extraction salt (Original method, 4g MgSO₄, 1g NaCl) were added to the sample in the 50 mL conical tube. The mixture was strongly shaken for 1 min and was centrifuged at 3,000g for 10 min. The acetonitrile layer was purification with dSPE (150mg MgSO₄, 25mg C18) and was centrifuged at 13,000g for 5min. The supernatant was filtered with a membrane filters (pore size: 0.2um) before analysis. ME (%, Matrix effect) for almost analytes range were -6.56 to 5.70%. MLOD (Method LOD) and MLOQ (Method LOQ) was calculated by S/N ratio. MLOQs were 0.01 mg/kg. The linear correlation coefficients (r2) were > 0.99 within the range of 2 ~ 100 ug/kg for all of the 3 imidazolinone herbicides. The percentages (of imidazolinone herbicides) recovers were in the range of 84.1 ~ 110.6% (0.01mg/kg level), 90.8 ~ 97.1% (0.1mg/kg level) and 94.4 ~ 102.1% (0.5mg/kg level) within the validation criteria (recover; 70-120% with RSD < 20%)

Effects of Chungkookjang Extract on Growth Hormone Secretion from GH3 Mouse Pituitary Cell and Growth Hormone Receptor Signaling Pathway

Sun Il Choi(최선일),Ji Eun Kim(김지은),In Sik Hwang(황인식),Hye Ryun Lee(이혜련),Young Ju Lee(이영주),Hong Joo Son(손홍주),Dong Seob Kim(김동섭),Kyu Min Park(박규민),Dae Youn Hwang(황대연) 한국생명과학회 2012 생명과학회지 Vol.22 No.9

뇌하수체 전엽에서 성장호르몬의 생산과 분비는 세포의 분열과 분화 그리고 이동을 조절하는 몇 가지 천연물질에 의해 유도된다. 따라서 발효과정을 통해 제조된 청국장이 성장호르몬의 대사에 미치는 영향을 평가하기 위하여 성장호르몬 분비능과 반응성을 뇌하수체 세포와 성장호르몬 표적세포에서 관찰하였다. 6가지 종류의 콩 품종으로 제조된 청국장 추출물 중에서, 대원, 대풍, 태광의 3종류 청국장 추출물은 5 mg/ml 농도에서 GH3 세포로부터 성장호르몬의 분비를 촉진하였다. 비록 세포 생존능은 이러한 추출물에 의해 유의적인 변화가 유도되지 않았으나, 성장호르몬의 분비량은 청국장 추출물의 농도에 의존적으로 증가하였다. 또한 성장호르몬의 표적 기관으로부터 유래된 MG63과 HepG2 세포는 GH3로부터 수집된 조건적 배양액에 의해 유의적으로 활성화되었다. 또한 이러한 세포에서 STAT5 발현은 대원 청국장 추출물을 처리 후, 15분 혹은 30분부터 세포질에서 유의적으로 증가하였으며, p-STAT5는 핵에서 30분 혹은 60분부터 증가하였다. 따라서 이러한 결과는 3가지 종류의 청국장 추출물은 성장호르몬의 분비를 촉진시키며, 청국장의 조건적 배양액은 성장호르몬 표적세포에서 신호전달을 유도함을 제시하고 있다. The production and secretion of growth hormone (GH) in the anterior pituitary gland can be induced by several natural products to control cell proliferation, differentiation, and migration. To investigate whether Chungkookjang (CKJ) produced by the fermentation process affects GH-related metabolism, the secretion and the response of GH were observed in pituitary cells and GH target cells. Among six CKJs manufactured by different strains of glycine max, only three CKJs, including Daewon (DW), Daepung (DP), and Taegwang (TG), induced GH secretion from GH3 cells at 5.0 mg/ml concentration. There were no significant changes detected in the viability of any of the cells treated with these CKJs. In addition, the increase in GH secretion from the GH3 cells was dependent on the concentration of the three types of CKJs. The proliferation of cell lines, including MG63 and HepG2 cells, that originated from those derived from the GH target organs was significantly activated by treatment with the GH-containing conditional medium (GCM) harvested from the three CKJ-treated GH3 cells, although their induction rate was different from each other. In these cells, p-STAT5 was maximally translocated into the nucleus of MG63 cells 30 min after DW treatment, while it was translocated in HepG2 cells at 60 min. These results suggest that these three types of CKJ could enhance the secretion of GH, as well as the GCM-derived response, in the two target organs.

적응 루프법을 이용한 진화적 구조 위상 최적설계

황승민,박재용,임민규,오영규,한석영 한국공작기계학회 2009 한국공작기계학회 춘계학술대회논문집 Vol.2009 No.-

This paper presents a reliability-based topology optimization (RBTO) using bi-directional evolutionary structural optimization (BESO). Topology optimization is formulated as volume minimization problem with probabilistic displacement constraint. Young's modulus, external load and thickness are considered as uncertain variables. In order to compute reliability index, four methods, i.e., RIA, PMA, SLSV and ADL(adaptive-loop), are used. Reliability-based topology optimization design process is conducted to obtain optimal topology satisfying displacement and reliability index constraints with the above four methods, and then each result is compared with respect to numerical stability and computing time.

영어 사역동사 보충절의 통사구조

황규홍,민지영 東亞大學校 2005 東亞論叢 Vol.42 No.-

This paper aims to investigate the syntax of causative verb clausal complements of make, have, let, and help in English within the minimalist framework outlined in Chomsky (1999, 2000, 2001), by emphasizing their constituency and categorial status. Generally, those syntactic causative verbs select bare infinitives as their complements, even though help also exceptionally takes another type of complements : to-infinitives. I put forward the proposals: i ) such causative verb clausal complements are single constituents, by examining a variety of constituency tests : coordination, reflexives, and expletives, and ii ) their categories are TPs whose head T is defective, lacking ∮ -complete.

선천성 수근관 증후군 1례 보고

이규훈,황치문,김민석,김희상,안경회 大韓再活醫學會 1998 Annals of Rehabilitation Medicine Vol.22 No.3

록인 증폭기에 의한 L(C,R) 회로 공진점 결정의 한 방법

정세민,홍진태,최규황,노지현 東亞大學校 附設 基礎科學硏究所 1994 基礎科學硏究論文集 Vol.11 No.1

L(C,R)회로의 공진점을 결정하기 위해 록인 증폭기에 의한 sequential spectrum analysis(SSA)법을 적용해 보았다. 시료는 변압기였으며, 단일 소인방식과 왕복 소인방식을 비교해 보았다. 또한 실험 결과의 신뢰도를 확인해보기 위해 실험결과를 변압기의 제작사 자료와 Q 미터(HP,4277A USA)에 의한 측정 결과와 비교하였다. 제작사 자료에 의하면 시료의 공진점은 두 권선의 각각은 5kHz(10kHz/2)였으나, 왕복소인에 의한 측정에서 시료의 공진점은 5.1kHz, 실험 결과로부터 계산된 Q 값은 4.3으로 주어졌고, 단일 소인법에 의해서는 공진점이 5.78KHz로 주어졌으며, Q 미터에 의한 Q 값은 4.9(9.8/2)였다. 실험 결과들과 기준 Q 미터에 의한 측정결과를 비교해본 결과, 양방향 소인법이 단일 방향소인법 보다 더 신뢰할 수 있음을 알 수 있었으며, SSA법에 의한 측정이 기존의 상용 전문기기에 의한 측정에 못지 않음과 전문기기의 측정 하한 문제를 극복하는 좋은 대안이 될 수 있음을 알 수 있었다. An accurate method named the sequential spectrum analysis(SSA) using a lock-in amplifier(LIA) of the heterodyne type was investigated to determine the resonance frequency of a LC(C,R) circuit : A heavy winding transformer was used as an inductor in the circuit. In this experiment, two types of the sweep method-one way and round trip method were examined. The resonance frequency of each method were compared with the manufacturer's data and those by the reference Q meter(HP,4277A, USA)for the experimental confidence: Measured resonance frequency by the round-trip method was 5.1 kHz, Q value at this frequency was about 4.3, while those by the single-sweep method were given by 5.78 kHz for the resonance frequency, 2.3 for the Q. On the other hand, the resonance frequency of manufacturer's data was 5 kHz and Q value by the reference Q meter was 4.9(9.8/2)at that frequency. From the comparison, it might be concluded that the SSA by the round-trip method was more reliable and accurate than the one-way method and relatively inexpensive, good alternative with respect to the professional instrument.

ESO기법을 이용한 신뢰성 기반 형상 최적설계

오영규,박재용,황승민,임민규,박재용,한석영 한국공작기계학회 2009 한국공작기계학회 춘계학술대회논문집 Vol.2009 No.-

This paper presents a reliability-based shape optimization (RBSO) using the evolutionary structural optimization (ESO). An actual design involves uncertain conditions such as material property, operational load and dimensional variation. The deterministic optimization (DO) is obtained without considering uncertainties related to uncertainty parameters. However, the RBSO can consider the uncertainty variables because it has the probabilistic constraints. In order to determine whether the probabilistic constraint is satisfied or not, simulation techniques and approximation methods are developed. In this paper, the reliability-based shape design optimization method is proposed by utilizing the reliability index approach (RIA), performance measure approach (PMA), single-loop single-vector (SLSV), adaptive-loop (AOL) are adopted to evaluate the probabilistic constraint. In order to apply the ESO method to the RBSO, a sensitivity number is defined as the change in the displacement. Numerical examples are presented to compare the DO with the RBSO. The results of design example show that the RBSO model more reliable than deterministic shape optimization.

신부전증과 폐에 Pseudolyrmphorma를 동만한 원발성 Sjogren 증후군 : Cyclophosphamide와 Prednisolone에 의한 성공적인 치료

강민규,구영선,황평주,김종학,나기량,서광선,이강욱,신영태 대한신장학회 2000 대한신장학회잡지 Vol.19 No.4

HFCVD법을 이용하여 제작한 n-형 다이아몬드 박막의 특성 연구

김병규,황윤식,권민철,김용,이재열,박홍준 동아대학교 기초과학연구소 2000 基礎科學硏究論文集 Vol.17 No.1

HFCVD법으로 암모니아 가스를 사용하여 n-형 도핑된 다이아몬드 박막을 제작하여, 기판온도와 암모니아 가스 첨가비에 따른 박막의 morphology의 변화를 조사하였다. 증착된 시료에 대한 SEM, Raman, XRD를 이용하여 박막의 특성을 분석하고, 도핑에 따른 전계방출 특성을 측정하였다. 양질의 n-형 도핑된 다이아몬드 박막을 증착시키기 위해 기판온도와 암모니아 첨가비에 따른 최적의 증착조건을 찾을 수 있었다. We fabricate n-doped diamond thin films by hot filament chemical vapor deposition method(HFCVD) using ammonia as a doping gas and investigate the effect of the substrate temperature and the ammonia gas ratio upon the diamond film morphology. The SEM, Raman spectroscopy, and the XRD analysis are executed to characterize film morphology. Field emission property of the film is measured also. We find optimum conditions of the substrate temperature and the ammonia gas ratio to deposit high quality n-doped diamond thin films.