8,200 research outputs found
Development of a fully integrated microfluidic system for sensing infectious viral disease
No full textAn active micromixer system utilizing the magnetic force was developed and examined for its ability to facilitate the mixing of more than two fluid flows. The mixing performance of the active micromixer was evaluated in aqueous-aqueous systems including dyes for visual observation. A complete analytical microfluidic system was developed by integrating various functional modules into a single chip, thus allowing cell lysis, sample preparation, purification of intracellular molecules, and subsequent analysis. Upon loading the cell samples and lysis solution into the mixing chamber, the integrated microfluidic device allows efficient cell disruption by rotation of a micromagnetic disk and control of mixing time using the Teflon-coated hydrophobic film as a microvalve. This inflow is followed by separating the cell debris and contaminated proteins from the cell lysate sample using the acrylamide (AAm)-functionalized SPE. The inflow of partially purified cell lysate sample containing the gold binding polypeptide (GBP)-fusion protein was bound onto the gold micropatterns by means of its metal binding affinity. The GBP-fusion method allows immobilization of proteins in bioactive forms onto the gold surface without surface modification suitable for studying antigen-antibody interaction. It was used for the detection of severe acute respiratory syndrome (SARS), an infectious viral disease, as an example case.This work was supported by the Basic Research Program of
the Korea Science & Engineering Foundation (R01-2006-000-
11175-0 for WHH and TJP) and by the IT Leading R&D Support
Project from the Ministry of Knowledge Economy through
IITA (SYL and TJP). Further supports by the LG Chem Chair Professorship and the KOSEF through the Center for Ultramicrochemical
Process Sytems (SYL) are appreciated. We also
thank K.-B. Lee (Korca Basic Science Institute, Korea) for his
kind advice for electrochemical analysis
Aircraft Wing Flutter Characteristics Considering Control Surface and Actuator Nonlinearity in Subsonic and Supersonic Regions
Full text linkThis research was supported by the Agency for Defense Development (ADD) and
Flight Vehicle Research Center(FVRC) in the Republic of Korea. This support is gratefully
acknowledged
Intonation of sentences with an NPI
No full textThis paper presents the results of a production experiment on the intonation of sentences containing a negative polarity item (NPI) in Tokyo Japanese. The results show that NPI sentences exhibit a focus intonation: the F0-peak of the word to which an NPI is attached is raised, while the pitch contour after the NPI-attached word is compressed until the negation. This intonation pattern is parallel to that of wh-question, in which the F0 of the wh-phrase is raised while the post-wh-contour is compressed until the question particle
A numerical study on the flow and sound fields of centrifugal impeller located near a wedge
No full textCentrifugal fans are widely used and the noise generated by these machines causes one of the serious problems. In general, the centrifugal fan noise is often dominated by tones at blade passage frequency and its higher harmonics. This is a consequence of the strong interaction between the flow discharged from the impeller and the cut-off in the casing. However, only a few researches have been carried out on predicting the noise because of the difficulty in obtaining detailed information about the flow field and considering the scattering effect of the casing. The objective of this study is to understand the generation mechanism of sound and to develop a prediction method for the unsteady flow field and the acoustic pressure field of the centrifugal impeller. A discrete vortex method is used to model the centrifugal impeller and a wedge and to calculate the flow field. The force of each element on the blade is calculated by the unsteady Bernoulli equation. Lowson's method is used to predict the acoustic source. In order to consider the scattering and diffraction effects of the casing, Kirchhoff-Helmholtz boundary element method (BEM) is developed. The source of Kirchhoff-Helmholtz BEM is newly developed, so the sound field of the centrifugal fan can be obtained. A centrifugal impeller and wedge are used in the numerical calculation and the results are compared with the experimental data. Reasonable results are obtained not only for the peak frequencies but also for the amplitudes of the tonal sound. The radiated acoustic field shows the diffraction and scattering effect of the wedge. (C) 2002 Elsevier Ltd. All rights reserved
H-INFINITY ROBUST-CONTROL OF FLEXIBLE MANIPULATOR VIBRATION BY USING A PIEZOELECTRIC-TYPE SERVO-DAMPER
No full textAn H(infinity) controller design scheme based on the matrix fraction stability condition is proposed for the vibration control of a flexible manipulator, which has the matrix fraction uncertainty. The proposed controller is then applied to the cantilever bearn with a piezoelectric-type servo-damper so that the vibration at the free end of the beam is effectively suppressed, while its effective length slowly changes
An analysis of the flow and aerodynamic acoustic sources of a centrifugal impeller
No full textThis work was partially supported by the Agency for Defense Development
The Syntax and Semantics of Korean Wh-Quantification: Wh-NPIs and Wh-In-Situ
Full text linkThis dissertation investigates the syntactic and semantic aspects of long-distance dependency involved in Korean wh-Negative Polarity Items (NPIs). Korean wh-NPIs consist of a wh-item and a focus particle -to meaning `also\u27 or `even\u27. In all reported cases, the wh-item and -to appear adjacent to each other. However, the wh-item and -to can appear discontinuously when the NPI licenser is located in a different clause from the wh-NPI. I will call this new form of wh-NPIs split wh-NPIs . The central claims of this dissertation are the following. The first, long-distance dependency displayed in split wh-NPIs is attained via overt movement of a focus particle -to `also/even\u27 in an effort to form a local relation with an NPI licenser. Second, -to is interpreted with its associated wh-item via point-wise semantic composition without forming a local relation at LF. These conclusions are motivated by finding two sets of new data: 1) split wh-NPIs cannot be formed across island boundaries, 2) split wh-NPIs are susceptible to focus intervention effects. This analysis has important implications for another wh-in-situ construction in Korean, wh-questions. By comparing split wh-NPIs with wh-in-situ questions, I argue that wh-in-situ questions do not involve any type of movement
Microcrystalline silicon films deposited by electron cyclotron resonance plasma chemical vapor deposition using helium gas
No full textWe have investigated the growth of microcrystalline silicon films by electron cyclotron resonance plasma chemical vapor deposition (ECR-PCVD) using He as the ECR gas at substrate temperatures in the range of 180 to 550 degrees C with He to silane ratios (He/SiH4) of 1: 4, and 9. With ratios of 4 and 9, the volume fractions of microcrystalline silicon increase with temperature and exceed 90% at 550 degrees C. To study the role of He plasma; we prepared silicon films using a layer-by-layer technique and found that long exposure to He plasma changes the structure of amorphous silicon to microcrystalline.This work was partially supported by the Korea Science and Engineering Foundation (KOSEF) through the Semiconductor Physics Research Center (SPRC)
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