• Proceedings of the Korean Society of Surveying, Geodesy, Photogrammetry, and Cartography Conference
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• 2004.11a
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• pp.95-98
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• 2004

GPS double difference, carrier phase measurements are ambiguous by an unknown inter number of cycle. High precision, relative GPS positioning can be obtained from a short time span of data if the integer double difference ambiguities can be determined efficiently. In this study, we used a ambiguities resolution method indicated by Clyde Goad. And I compared with ambiguities using Lambda method. The difference of ambiguities between two method is below ${\pm}$1.

• 한국전산유체공학회:학술대회논문집
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• 2008.03a
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• pp.131-136
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• 2008

Three-dimensional characteristics of fluid flow and heat transfer around a wavy circular cylinder having sinusoidal variation in cross sectional area along the spanwise direction are numerically investigated using the immersed boundary method. The three different wavelengths of ${\pi}/4$, ${\pi}/3$ and ${\pi}/2$ and at the fixed wavy amplitude of 0.1 have been considered to investigate the effects of waviness on especially the forced convection heat transfer around a wavy cylinder when the Reynolds and Prandtl numbers are 300 and 0.71, respectively. The present computational results for a wavy cylinder are compared with those for a smooth cylinder. The time- and total surface-averaged Nusselt number for a wavy cylinder with is larger than that for a smooth cylinder, whereas that with ${\lambda}={\pi}/4$ and ${\pi}/3$ is smaller than that for a smooth cylinder. However, because the surface area exposed to heat transfer for a wavy cylinder is larger than that for a smooth cylinder, the total heat transfer rate for a wavy cylinder with different wavelengths of ${\lambda}={\pi}/4$, ${\pi}/3$ and ${\pi}/2$ is larger than that for a smooth cylinder.

• Korean Journal of Optics and Photonics
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• v.26 no.4
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• pp.217-225
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• 2015

This paper shows the best selection and combination of glass in lens design, to correct a chromatic aberration using achromatic and apochromatic conditions. Using this research result, we have designed a telecentric lens for machine vision in the full range of visible light. We obtain good optical quality in the form of a quite small RMS wavefront error of $0.057{\lambda}$ in the super-broadband wavelength range 380 nm -780 nm. This result is better than that for a common telecentric lens in the visible wavelength range 486.1-656.2 nm.

• Journal of the Korean Vacuum Society
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• v.17 no.5
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• pp.455-460
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• 2008

In recent years, there has been highly interestedin pulsed laser deposition (PLD) method for fabrication of the organic thin films, as an alternative to conventional fabrication method such as vacuum evaporation and spin coating techniques. In this study, organic thin films of $Alq_3$ (aluminato-tris-8-hydroxyquinolate) and TPD for organic light emitting diodes (OLED) were deposited by PLD using KrF excimer ($\lambda$=278 nm) laser in nitrogen atmosphere. Deposited films were evaluated by photoluminescence(PL), Fourier-transform Infrared Spectroscopy (FT-IR) to study the effect of the laser and $N_2$ atmosphere parameters on the structural and optical properties.

• Analytical Science and Technology
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• v.11 no.6
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• pp.429-435
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• 1998

Free and glycine conjugated bile acids were detected fluoromatrically in high-performance liquid chromatography after derivatization with dansyl cadaverine. The coupling agent, diethyl phosphorocyanidate was used to form the amide bond between dansyl cadaverine and analytes. The dansyl derivatives of 8 bile acids were separated successfully on Cosmosil ODS column by using linear gradient elution of 20% MeOH-water/$CH_3CN$. The detection limits of cholic acid was reached 10 pg(S/N=5) per $1{\mu}l$ of injected volume. This new derivatization method would be applicable to detect the changes of bile acids in biological samples.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.11 no.2
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• pp.206-216
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• 2000

In this paper, the linear tapered slot(LTS) antenna and linear constant tapered slot(LCTS) antenna are optimized for millimeter-wave antenna by the finite difference time domain(FDTD) method and then fabricated and measured. The microstrip-to-slot transition is proposed with the widen $\lambda$/4 open stub as feeder for wide bandwidth of 16.5GHz($VSWR\leq2$). The results of the calculation and measurement, the bandwidth of LTS antanna is 8.3GHz(26.47%) and 7.1792GHz(22.4%) respectively. Also, the bandwidth of LCTS antenna is 8.1GHz(26.47%) and 6.3243GHz(20.43%) respectively.

• The Transactions of the Korean Institute of Electrical Engineers C
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• v.49 no.2
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• pp.125-131
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• 2000

A high resolution Laser Doppler Vibrometer(LDV) developed using electronic fringe counting method. The fringe pattern signal obtained via analog signal processing is divided into two. One was converted to a TTL signal with a ZCD(zero-crossing detector) and then counted to calculate the displacement due to the vibration. The other was directed to the A/D converter to get a high resolution of about $\lambda/320$ with the phase comparison method. The data obtained with the A/D converter was used in the displacement calculation and the result was displayed on a LCD pane. In this study, a Laser Doppler Vibrometer with measurement range of $0.32\mum~129\mum$ and displacement resolution of 2nm, about $\lambda/320$ , was developed. And this LDV can be used to measure the dynamic of microsize devices such as MEMS(Micro Electro-Mechanical Systems) and to diagnose high capacity electric equipment such as circuit breakers and transformers, of which resonant frequencies are changed when they are damaged.

• YAKHAK HOEJI
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• v.36 no.5
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• pp.506-511
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• 1992

The Prostaglandins were derivatized rapidly with monodansyl cadaverine as a fluorophore in mild conditions. The carboxylic moiety of prostaglandins was activated with diethyl phosphorocyanidate and successively coupled with fluorophore in dimethylformamide at room temperature. The labeling yield was reached about 95% at 15 min using arachidic acid $(C_{20:0})$ as a test sample. This derivative showed constant fluorescent intensity at $4^{\circ}C$ for 180 days. The derivatives of prostaglandins were shown high solvent selectivity with tetrahydrofuran in reversed-phase column. therefore, these derivatives could be successfully separated on YMC pack A-212(S-5 120A C8) column in tetrahydrofuran-based eluents. The detection limits of these derivatives was ca. 500 fmol and determination limits was ca. 5 pmol as injected amount in fluorescent detection $({\lambda}ex.\;340\;nm,\;{\lambda}em.\;520\;nm)$. In this method, the ranges of recovery and coefficient of variation were $93.6{\sim}102.7%$ and $4.3{\sim}5.8%$, respectively.

• Bulletin of the Korean Chemical Society
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• v.30 no.5
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• pp.1026-1030
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• 2009

A novel Schiff base ligand (N, O system) 5-methoxy-2-phenyliminomethylphenol ($5-CH_3O-PMP$) was synthesized. Using the synthesized ligand as a fluorescent reagent, a fluorometric method was developed for the quantitative analysis of Al(III) ion. The quantitative analysis of Al(III) ion was performed by making the complex compound between Al(III) ion and $5-CH_3O-PMP$ in ethanol-water solution (85/15, v/v, pH 6.2). The excitation wavelength (${\lambda}em$) of the complex compound was 397 nm while the emmision wavelength (${\lambda}em$) was 498 nm. The quantitative analysis of Al(III) ion was carried out by estimating the fluorescence intensity. The various calibration curves were used for the quantitative analysis in the range of 0.27$\sim$27 ng/mL Al(III) ion concentrations. The detection limit was 0.027 ng/mL. Using the fluorometric method developed in this study, satisfying results were obtained from various samples such as tap water, hot spring water, river water, sea water and waste water, which contained considerable amounts of interfering ions.

• Bulletin of the Korean Chemical Society
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• v.25 no.6
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• pp.900-906
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• 2004

An RPLC-postcolumn detection method has been developed for the fluorimetric determination of dichloroacetamide (DCAD) in water. After ammonia and DCAD were separated on a $C_{18}$ nonpolar stationary phase with 2.5% methanol-0.02 M phosphate buffer at pH 3, the column eluant was reacted with post column reagents, o-phthaldialdehyde (OPA) and sulfite ion at pH 11.5, to produce a highly fluorescent isoindole fluorophore, which was measured with a fluorescence detector ( ${\lambda}_{ex}$ = 363 nm, ${\lambda}_{em}$ = 425 nm). With the optimized conditions for RPLC and the postcolumn derivatization, the calibration curve was found to be linear in the concentration ranges of 0.5 and 20 ${\mu}$M for DCAD, and the detection limit for DCAD was 0.18 ${\mu}$M (23${\mu}$g/L). This corresponded to 18 pmol per 100 ${\mu}$L injection volume for a signal-to-noise ratio of 3, and the repeatability and reproducibility of this method were 1.0% and 2.5% for five replicate analyzes of 2 ${\mu}$M DCAD, respectively. The degradation yields DCAD to ammonia were 94 and 99%, and the percent recoveries of DCAD from 4 and 6 ${\mu}$M DCAD-spiked tap water were shown mean more than 97%.