• KSBB Journal
• /
• v.22 no.6
• /
• pp.426-432
• /
• 2007

We have developed a sensitive, one-step, homogeneous open sandwich fluoroimmunoassay (OsFIA) based on fluorescence resonance energy transfer (FRET) and luminescent semiconductor quantum dots (QDs). In this FRET assay, estrogen receptor-$\beta$ (ER-$\beta$) antigen was incubated with QD-labeled anti-ER-$\beta$ monoclonal antibody and AF (Alexa Fluoro)-labeled anti-ER polyclonal antibody for 30 minutes, followed by FRET measurement. The dye separation distance was estimated to be between $80\sim90\;{\AA}$. The present method is rapid, simple and highly sensitive, and did not require the bound/free reagent separation steps and solid-phase carriers. A concentration as low as 0.05 nM (2.65 ng/ml) receptor was detected with linearity ($R^2$ > 0.990). In addition, the assay was performed with commercial antibodies. This assay provides a convenient alternative to conventional, laborious sandwich immunoassays.

• Korean Chemical Engineering Research
• /
• v.43 no.3
• /
• pp.360-365
• /
• 2005

SMB (simulated moving bed) is a continuous chromatographic process by shifting periodically port position. Binary of mixture, Blue dextran and Orange G, was separated by SMB. These components have unique color individually, that is, Blue dextran is blue and Orange G is orange. It is easy to understand SMB process by observing the shift of color changes in SMB. These components was not adsorbed to stationary phase and isolated by difference of size exclusion factor. Mass transfer coefficient was determined by single pulse test under several flow rate conditions. Operation condition was obtained by standing wave theory and optimized for high purities in extract and raffinate streams. Experiment was performed in open loop 4 zone (2-2-2-2) SMB. There are several advantages in open loop SMB, where extract is product for high purity. It is also easy to control flow rate and monitor experimental state during operation. Experimental, extract and raffinate history is well fitted with simulation results, however, column concentration profile is a little different from simulation results. Purities were 99.5％ for extract and 98.9％ for raffinate and extract and raffinate yields were obtained as 98.9％ and 99.4％ respectively.

• Proceedings of the Korean Institute Of Construction Engineering and Management
• /
• 2007.11a
• /
• pp.48-53
• /
• 2007

A project manager of construction project must analyze risks which might happen during the construction phase and prepare a restoration method against the risks in order to get the successful project's accomplishment. Insurance is a representative kind of risk transfer method and an institution which prevents damages of the insured. In spite of increasing the ratio of construction insurance policy in the construction industry, project managers have regarded the insurance as a formal action in the budget through insurance companies' guides. These aspects make them not be able to valuate the reasonableness of premium rate and the real amount of the risks. This thesis is to present an improved method of construction insurance contract. Firstly, the status of the current construction insurance system have been anlyzed and the problems have been deducted. Secondly the development direction against the problems is presented in the research. Lastly, the procedure model is proposed for acquiring the resonable premium rate of insurance.

• Journal of Information Display
• /
• v.4 no.2
• /
• pp.13-18
• /
• 2003

We synthesized bis (2-methyl-8-quinolinolato)(triphenylsiloxy) aluminum (III) (SAlq), a blue-emitting material having a high luminous efficiency, through a homogeneous-phase reaction. The photoluminescence (PL) and electroluminescence (EL) spectra of SAlq show two peaks at 454 nm and 477 nm. Efficient white light-emitting devices are fabricated by doping SAlq with a red fluorescent dye of 4-dicyanomethylene-2-methyl-6-{2-(2,3,6,7-tetrahydro-1H,5H-benzo[i,j]quinolizin-8yl) vinyl}-4H-pyran (DCM2). The incomplete energy transfer from blue-emitting SAlq to red-emitting DCM2 results in light-emission of both blue and orange colors. Devices with the structure of ITO/TPD (50 nm)/SAlq:DCM2 (30 nm, 0.5 %)/$Alq_3$ (20 nm)/LiF (0.5 nmj/Al show EL peaks at 456 nm and 482 nm originating from SAlq and at 570 nm from DCM2, resulting in the Commission Internationale d'Eclairage (CIE) chromaticity coordinates of (0.32, 0.37). The device exhibits an external quantum efficiency of about 2.3 % and a luminous efficiency of about 2.41m/W at 100 $cd/m^2$. A maximum luminance of about 23,800 $cd/m^2$ is obtained at the bias voltage of 15 V.

• Journal of the Korean Electrochemical Society
• /
• v.14 no.1
• /
• pp.50-55
• /
• 2011

To enhance the performance of a MEA (membrane electrode assembly) in a polymer electrolyte membrane fuel cell (PEMFC), optimum contents of Nafion ionomer as electrolyte in the 20 and 40 wt% Pt/C used in electrodes were examined. Variety characterization techniques were applied to examine optimum Nafion contents: cell performance test, electrochemical impedance spectroscopy (EIS), and cyclic voltammetry (CV). According to Pt wt% supported on carbon support, it has been observed that polarization, ohmic, and mass transfer resistances were changed so that the cell performance was significantly dependent on the content of Nafion ionomer. Optimum Nafion ionomer contents in the 20 wt% Pt/C and 40 wt% Pt/C were showed 35 wt% and 20 wt%, respectively. This is due to different surface area of the Pt/C catalyst, and formation of triple phase boundary seems to be affected by the Nafion contents.

• Journal of the Microelectronics and Packaging Society
• /
• v.6 no.4
• /
• pp.23-33
• /
• 1999

A finite element method was employed fort thermal and stress analyses of an IGBT module of 3-phase full bridge. The effect of material parameters such as substrate material, substrate area, solder thickness on the temperature and stress distributions of the module packages has been investigated. Thermal analysis results have also been compared by setting of boundary conditions such as equivalent heat transfer coefficient or constant temperature at a base metal surface of the package. The increase of ceramic substrate area up to 3 times does little contribution to the reduction(8.9%) of thermal resistance, while contributed a lot to the reduction(60%) of thermal stress. Thicker solder resulted in higher thermal resistance but did slightly reduced thermal stresses. It is revealed by the stress analysis that maximum stress was induced at the region of copper pads which are bonded with ceramic substrate.

• Journal of the Korea Institute of Information and Communication Engineering
• /
• v.4 no.1
• /
• pp.179-189
• /
• 2000

Recently, due to the increasing interests in deep sea development, all possible efforts to the development of underwater unmanned working vehicles such as AUV(Autonomous Underwater Vehicle) or underwater robot are exerted. This paper proposes a new efficient acoustic-based underwater image data communication system, which ensures a certain level of maximum throughput regardless of the propagation delay of ultrasonic and allowsfast data transmission through the multiple ultrasonic communication channel. Proposed system consists of an acoustic transducer which operates at 136kHz center frequency and it's 10kHz bandwidth, pre-amplifier, $\pi/4 QPSK$(Quadrature Phase Shift Keying) modulation/demodu-lation method, image compressing method using JPEG technique and modified Stop & Wait protocol. The experimental result of the system make it possible to transfer the underwater image as a high throughput at the basin test. The results of test are also verified which allows to desirable transmission performance compared with the existing developed system and the possibility to put the practical use of survey and investigation in the water.

• The Transactions of the Korea Information Processing Society
• /
• v.5 no.3
• /
• pp.681-687
• /
• 1998

The paper presents a hybrid mcthod for disambiguation of the verb meaning in the machine translation. The presented verb translation algorithm is to perform the concept-based method and the statistics-based method simultaneously. It uses a collocation dictionary, WordNct and the statistical information extracted from corpus. In the transfer phase of the machine translation, it tries to find the target word of the source verb. If it fails, it refers to Word Net to try to find it by calculating word similarities between the logical constraints of the source sentence and those in the collocation dictionary. At the same time, it refers to the statistical information extracted from corpus to try to find it by calculating co-occurrence similarity knowledge. The experimental result shows that the algorithm performs more accurate verb translation than the other algorithms and improves accuracy of the verb translation by 24.8% compared to the collocation-based method.

• Proceedings of the KIEE Conference
• /
• 2005.07c
• /
• pp.2410-2412
• /
• 2005

In this study, two types of PS substrate were fabricated for sensing of chemical and biological substances. For sensing of the humidity and chemical analyzes such as $CH_3OH$ or $C_2H_5OH$, PS layers are prepared by photoelectrochemical etching of silicon wafer in aqueous hydrofluoric acid solution. To evaluate their sensitivity, we measured the resistance variation of the PS diaphragm. As the amplitude of applied voltage increases from 2 to 6Vpp at constant frequency of 5kHz, the resistance variation for humidity sensor rises from 376.3 to $784.8{\Omega}$/%RH. And the sensitivities for $CH_3OH$ and $C_2H_5OH$ were 0.068 uA/% and 0.212 uA/%, respectively. For biological sensing application, amperometric urea sensors were fabricated based on porous silicon(PS), and planar silicon(PLS) electrode substrates by the electrochemical methods. Pt thin film was sputtered on these substrates which were previously formed by electrochemical anodization. Poly (3-methylthiophene) (P3MT) were used for electron transfer matrix between urease(Urs) and the electrode phase, and Urs also was by electrochemically immobilized. Effective working area of these electrodes was determined for the first time by using $Fe(CN)_6^{3-}/Fe(CN)_6^{4-}$ redox couple in which nearly reversible cyclic voltammograms were obtained. The $i_p$ vs $v^{1/2}$ plots show that effective working electrode area of the PS-based Pt thin film electrode was 1.6 times larger than the PLS-based one and we can readily expect the enlarged surface area of PS electrode would result in increased sensitivity by ca. 1.6 times. Actually, amperometric sensitivity of the Urs/P3MT/Pt/PS electrode was ca 0.91uA/$mM{\cdot}cm^2$, and that of the Urs/P3MT/Pt/PLS electrode was ca. 0.91uA/$mM{\cdot}cm^2$ in a linear range of 1mmol/L to 100mmol/L urea concentrations

• Journal of Microbiology and Biotechnology
• /
• v.22 no.12
• /
• pp.1698-1704
• /
• 2012

Resveratrol, or its glycoside form piceid, is a dietary antioxidant polyphenolic compound, found in grapes and red wine that has been shown to have protective effects against cardiovascular disease. However, very low water solubility of the compound may limit its application in the food and pharmaceutical industries. The amylosucrase (AMAS) of Alteromonas macleodii Deep ecotype was expressed in Escherichia coli and showed high glycosyltransferase activity to produce the glucosyl piceid when piceid was used as an acceptor. The conversion yield of piceid glucoside was 35.2%. Biotransformation using culture of the E. coli harboring the amas gene increased the yield up to 70.8%. The transfer product was purified by reverse phase chromatography and recycling preparative HPLC, and the molecular structure of the piceid glucoside was determined using NMR spectroscopy. The piceid glucoside was identified as glucosyl-${\alpha}$-($1{\rightarrow}4$)-piceid. The solubility of glucosyl piceid was 5.26 and 1.14 times higher than those of resveratrol and piceid, respectively. It is anticipated that dietary intake of this compound is more effective by enhancing the bioavailability of resveratrol in the human body because of its hydrophilic properties in the intestinal fluid.