DSpace Collection:https://pubs.kist.re.kr/handle/123456789/753622026-02-10T19:14:22Z2026-02-10T19:14:22ZA novel pressure sensing mechanism in a microchannel based on the surface tension and thermodynamic p-v-T relationLee, Sang-YoupWereley, Steve T.https://pubs.kist.re.kr/handle/201004/1338702024-04-25T22:05:14Z2008-01-01T00:00:00ZTitle: A novel pressure sensing mechanism in a microchannel based on the surface tension and thermodynamic p-v-T relation
Authors: Lee, Sang-Youp; Wereley, Steve T.
Abstract: A simple and cost-effective pressure sensing mechanism which can readily be used to increase measurement resolutions has been introduced. The proposed method measures the local static water pressure in a microchannel using the surface tension and thermodynamic p-v-T relation of air. The idea was tested using a microchannel along which a series of closed-end taps were perpendicularly placed. The prototype device was fabricated with SU-8, a negative photoresist. The dimension of the microchannel was 50 mu m x 7 mu m x 2.4 mm (W x H x L). The closed-end taps were located every 100 mu m along the microchannel with various dimensions of 5-20 mu m x 7 mu m x 500-1500 mu m (W x H x L). The surface tension was calculated through contact angle measurement on the water-air-SU-8 interface. Experiments were performed by imaging the meniscus location and were compared with analytical calculations. The proposed pressure sensing method showed good agreement with the analytical predictions and feasibilities as a valid pressure sensing mechanism in a microscale flow.2008-01-01T00:00:00ZAnalysis of polyamines as carbamoyl derivatives in urine and serum by liquid chromatography-tandem mass spectrometryByun, Jeong AhLee, Sang HeeJung, Byung HwaChoi, Man HoMoon, Myeong HeeChung, Bong Chuhttps://pubs.kist.re.kr/handle/201004/1338692024-04-25T22:05:11Z2008-01-01T00:00:00ZTitle: Analysis of polyamines as carbamoyl derivatives in urine and serum by liquid chromatography-tandem mass spectrometry
Authors: Byun, Jeong Ah; Lee, Sang Hee; Jung, Byung Hwa; Choi, Man Ho; Moon, Myeong Hee; Chung, Bong Chu
Abstract: A quantitative analysis of polyamines in urine and serum by liquid chromatography-tandem mass spectrometry (LC-MS/MS) is described. The polyamines were carbamylated with isobutyl chloroformate, extracted with diethyl ether under pH 9.0, and analyzed by LC-MS/MS with single reaction monitoring mode. The limit of quantification was 1 ng/mL based on a signal-to-noise ratio > 3, and the correlation coefficient (r(2)) for the calibration curves was > 0.99 for both urine and serum samples. The present method was applied to urine and serum samples from 30 breast cancer patients and 30 normal female controls. There was no significant difference in the urinary polyamine levels between breast cancer patients and controls. However, 1,3-diaminopropane, putrescine, spermine and N-acetylspermidine levels in serum increased in breast cancer patients. These four serum polyamines may be a good index to study both production and metabolism of polyamines, and a useful tool in assessment of the polyamine status of breast cancer patients. Copyright (c) 2007 John Wiley & Sons, Ltd.2008-01-01T00:00:00ZPropagation of shear bands in a Cu47.5Zr47.5Al5 bulk metallic glassKim, K. B.Das, J.Lee, M. H.Yi, S.Fleury, E.Zhang, Z. F.Wang, W. H.Eckert, J.https://pubs.kist.re.kr/handle/201004/1338682024-04-25T22:05:09Z2008-01-01T00:00:00ZTitle: Propagation of shear bands in a Cu47.5Zr47.5Al5 bulk metallic glass
Authors: Kim, K. B.; Das, J.; Lee, M. H.; Yi, S.; Fleury, E.; Zhang, Z. F.; Wang, W. H.; Eckert, J.
Abstract: We report a novel finding of slither propagation of shear bands on the fracture surface of a Cu47.5Zr47.5Al5 bulk metallic glass (BMG). The nanoscale heterogeneities in the as-cast state are aggregated along shear bands with irregular morphology. Such heterogeneities create a fluctuating stress field during shear band propagation leading to a slither propagation mode. The slither propagation of 10 to 15 nm wide shear bands is effective to improve both the plasticity and the "work-hardening-like" behavior of BMGs if the size, the morphology, and the elastic properties of the heterogeneities are intimately intercalated during solidification.2008-01-01T00:00:00ZNovel thixotropic gel electrolytes based on dicationic bis-imidazolium salts for quasi-solid-state dye-sensitized solar cellsKim, Jun YoungKim, Tae HoKim, Dong YoungPark, Narn-GyuAhn, Kwang-Dukhttps://pubs.kist.re.kr/handle/201004/1338672024-04-25T22:05:07Z2008-01-01T00:00:00ZTitle: Novel thixotropic gel electrolytes based on dicationic bis-imidazolium salts for quasi-solid-state dye-sensitized solar cells
Authors: Kim, Jun Young; Kim, Tae Ho; Kim, Dong Young; Park, Narn-Gyu; Ahn, Kwang-Duk
Abstract: Novel thixotropic gel electrolytes have been successfully prepared by utilizing oligomeric poly(ethylene oxide) (PEO)-based bis-imidazolium diiodide salts and hydrophilic silica nanoparticles for application in quasi-solid-state dye-sensitized solar cells (DSSCs). The thixotropic gel-state of the ionic liquid-based composite electrolytes is confirmed by observing the typical hysteresis loop and temporary hydrogen bonding. On using the PEO-based composite electrolyte, a quasi-solid-state DSSC exhibited highly improved properties such as easy penetration of the electrolyte into the cell without leakage, long-term stability, high open-circuit voltage without the use of 4-tert-butylpyridine, and a high energy-conversion efficiency of 5.25% under AM 1.5 illumination (100 m W cm(-2)). (c) 2007 Elsevier B.V. All rights reserved.2008-01-01T00:00:00Z