• Journal of the Korea Society of Computer and Information
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• v.9 no.4 s.32
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• pp.185-189
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• 2004

In this paper, designed a diode detector and a log chip detector for mobile communication, and its application is proposed by compared results. In practice, fabricated a diode detector have showed detection voltage of $0{\sim}0.7V$ to RF input power of $-40dBm{\sim}-10dBm$, therefore it has suitable characteristic for small variable signal detection. And a log chip detector have showed wide dynamic range of 65dB, and $1.5{\sim}4.5V$ detection voltage to RF input power of $-65dBm{\sim}0dBm$. therefore we have found that it suit peak power measurement because it had insensible output detection voltage.

• Journal of the Korean Society of Radiology
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• v.9 no.2
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• pp.73-77
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• 2015

In order to observe the detailed structure of the detector, it was CT scanned to reproduce the detailed structure of the crystal shapes and traverse layer using the Monte Carlo calculation applying the detector model. The uncertainty of measurement was lowered by adjusting the detector core by the edge effect at a higher energy (400 keV or higher) through the offset of peak efficiency of the gamma ray at low energy. It was confirmed that there was the appropriate matching with spatial dependency using the PENELOPE calculation. That was achieved by adjusting the parameters describing the crystal core and rounding of edge and crystal core.

• Journal of radiological science and technology
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• v.35 no.4
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• pp.315-319
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• 2012

The aim of this study was to develop a signal process circuit for a position sensitive avalanche photodiode detector. The circuit parts consisted of amplification, differential and peak/hold circuit. This research was the baseline to develop highly compact radiation detector. The signal was amplified by an amplification chip and its shape was changed in a differential circuit to minimize the pulse tailing. The peak/hold circuit detect the peak of the signal from the differential circuit and hold the amplitude of the peak for data acquisition. In order to test the intrinsic function of the circuit, the input signal was transmitted from a commercial pulse generator.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.11 no.5
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• pp.47-52
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• 2011

We studied about the damaged tire decision algorithm that measured dominant period of ultrasonic signal due to a foreign material on the friction between tire and road surface. We computed the power spectrum about the envelope of ultrasonic signal acquired from the damaged tire, then proposed the dominant period decision algorithm by statistical power threshold value. As the result of simulation, when driving by the speed of 80km/h, the 100ms of dominant period that measured in the proposed algorithm is more accurate than the 97.6ms of power spectrum peak period referenced on the average period of ultrasonic signal envelope peak, 101.24ms.

• Proceedings of the Korean Vacuum Society Conference
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• 2014.02a
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• pp.131-131
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• 2014

양자점은 전통적인 유기 염료에 비해 흡광영역이 넓고 발광 피크의 폭이 좁으며, 흡광과 발광 사이의 에너지 차가 커서 검출이 용이하고, 광안정성이 우수할 뿐만 아니라, 단순히 크기를 조절함으로써 발광 피크의 에너지를 제어할 수 있는 특장 때문에 많은 연구가 진행되었다. 그러나 많은 나노입자들과 마찬가지로 실질적인 응용을 위해서는 양자점 나노입자들도 대부분 표면개질을 거쳐야 하는데, 이 과정이 까다롭고 또 표면개질 중에 나노입자들의 응집이 일어나거나 광특성이 나빠지는 등의 문제가 흔히 발생한다. 한편, 서브미크론 크기의 입자들은 나노입자에 비해 응집현상이 미미해서 상대적으로 취급이 용이하다. 그 중에서도 실리카 입자들은 합성방법도 쉽게 확립되어 있고 생체친화성이 우수하며 그 표면화학 반응이 이미 잘 알려져 있어서 활용하기가 매우 용이하다. 따라서 양자점 층을 실리카 표면 가까이에 자기조립을 통해 배열한 하이브리드 구조는 양자점의 장점을 편리하게 이용할 뿐만 아니라 실리카의 표면개질 특성도 그대로 이용할 수 있다는 이중의 장점이 있다. 본 논문에서는 코어/쉘 구조로 안정화된 II-VI 반도체 양자점 층을 아래 그림 1과 같이 실리카 콜로이드 내에 배열한 하이브리드 구조를 소개하고, 이 하이브리드 구조를 표면개질 하여 LED 칩 위에 패키징 함으로써 백색광을 제조한 연구 및 더 나아가 중심에 초상자성 클러스터 핵을 배치하고 이를 둘러싼 실리카 콜로이드 표면 가까이에 양자점 층을 배열한 초상자성 하이브리드 구조를 합성하여 이를 on-site sensor에 적용한 연구 결과를 소개한다.

• Journal of the Korean Chemical Society
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• v.39 no.1
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• pp.23-28
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• 1995

Differential-pulse cathodic stripping voltammetry was applied to the Sn(II)-cupferron complex in 0.1 M acetate buffer solution (pH 4.20). Effects of solution pH, ligand concentration, accumulation potential, and accumulation time on the reduction peak current for the adsorptive complex of Sn(II)-cupferron were investigated. Interferences by other metal cations that affected on reduction peak current were also discussed. The detection limit was 3.1${\times}$10-9 M (0.37 ppb) of Sn(II) with 60 seconds accumulation time. The relative standard deviation (n=8) for 5${\times}$10-8 M Sn(II) was 3.0%.

• Journal of the Korean Chemical Society
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• v.40 no.3
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• pp.196-201
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• 1996

The analysis of trace cadmium in blood by using 10 folds diluted samples with 1% Triton X-100 and Fork platform tube at the ashing temperature of 500$^{\circ}C$ has been performed by GFAAS. In this study, good analytical results were obtained from peak area and peak height methods. The detection limits of SH and $D_2$ arc background correction are 0.02 ng/mL and 0.01 ng/mL, respectively. Relative standard deviation is within 5% at the level of 1.0 ng/mL.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.28 no.4C
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• pp.406-412
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• 2003

A fast multiple object motion detection method using periodogram has been proposed. Each frame is projected to vertical and horizontal directions, and then temporal FFT is applied. A line in two dimensional frequency domain indicates velocity. To estimate the velocity of an object, we intergrate along a line which passes through the origin in frequency domain. If a frame contains multiple moving objects, multiple peaks are detected corresponding to the velocity of each object. After pairing these peaks, we can determine the velocities of an object. In the proposal method we can easily pair horizontal and vertical velocity components efficiently with simple computation by combining projections in 45$^{\circ}$ and 135 $^{\circ}$ directions in addition to the vertical and horizontal direction.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.19 no.3
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• pp.152-158
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• 2009

Various fabrication methods have been used to synthesize sapphire which has qualities of jewelry well beyond the industrial class. Among them, the flux sapphire of Chatham Company which has as high value as jewelry was selected in order to compare natural and synthetic sapphire. First, the WD-XRF (Wavelength dispersive x-ray fluorescence spectrometer) was used to analyze the chemical composition of natural and synthetic sapphire. Although natural sapphire had very diverse chemical compositions, flux sapphire had small quantities of Mo, Pt and Pb elements in addition to the similar chemical ingredients to natural one. Pt is decisive proof of flux sapphire. Next, by investigating spectroscopic characteristics using UV-VIS Spectrophotometer after heat treatment at high temperatures of $1300^{\circ}C$ and $1500^{\circ}C$, the variation of 690 nm absorbance related to $Cr^{3+}$ was detected in the natural sapphire while those of the 690 nm absorbance (related to $Cr^{3+}$) as well as absorbance of 376 nm and 388 nm ($Fe^{3+}$) were seen in the flux sapphire. It was found that the difference in the absorbance variation of flux sapphire is greater than that of natural sapphire after heat treatment. The chemical composition and spectrum analysis were utilized to compare the natural sapphire and the flux synthetic sapphire.

• Journal of the Korean Chemical Society
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• v.41 no.11
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• pp.590-593
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• 1997

Square-wave anodic stripping voltammetry was applied to the germanium(IV)- Morin complex in 0.5 M sulfuric acid as a supporting electrolyte. The peak potential appeared at - 0.606 V vs. Ag/AgCl. Effects of sulfuric acid concentration, Morin concentration, accumulation potential, and accumulation time on the stripping peak current for the complex of germanium(IV)-Morin were studied. Interferences by other metal cations that affect on stripping peak current were also investigated. The detection limit was found to be $3.76{\times}10^{-7}M(27 {\mu}g/L)$ for germanium(IV) using 60 seconds of accumulation time. The relative standard deviation (n=8) for 0.4 mg/L($5.5{\times}10^{-6}$ M) germanium(IV) was 3.2%.