• Journal of the Korean Vacuum Society
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• v.15 no.1
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• pp.24-30
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• 2006

Integrated cavity output spectroscopy(ICOS) is a simple, non-intrusive absorption measurement technique that can detect and quantify trace-level gas species. The spectral absorbance of a gas is quantified from the integrated optical output of the modulated high-finesse cavity containing the sample which is irradiated by a wavelength-swept laser source. We constructed an experimental setup by using a tunable single mode external cavity diode laser operating at the wavelength near 765 nm and a Fabry-Perot cavity with length modulation achieved by a piezoelectric transducer where one of the cavity mirrors sat on. In the experiment performed on minute oxygen gas at the wave-length near 764.5nm, we demonstrated the minimum detectable absorption of $8.45\times10^{-8}cm^{-1}$.

• 대한방사선방어학회:학술대회논문집
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• 2009.11a
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• pp.174-175
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• 2009

• 대한방사선방어학회:학술대회논문집
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• 2011.11a
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• pp.224-225
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• 2011

• 대한방사선방어학회:학술대회논문집
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• 2009.04a
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• pp.200-201
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• 2009

• Journal of the Korean Chemical Society
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• v.44 no.4
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• pp.322-327
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• 2000

A new absorption spectrometric method for the determination of the Cr$_2O_7^{2-}$ ionin acidic media has been developed. The new method is based on the oxidation-reduction reaction of the HCr$O_4^-$ ion with H$_2$O$_2$forming a deep blue CrO(O$_2$) $_2$ andis coupled with a technique of flow injection analysis(FIA). The new method provides a linear calibration curve which accurately follows the Beer's law over a wide range of the analytical concentrations(2.0 ${\times}$ $10^{-6}$M~8.0 ${\times}$ $10^{-3}$M) of K$_2$Cr$_2$O$_2$. The sensitivity of the new method is approximately two times greater than the current method and the effects of the interfering substances such as V, Co, Ni, Fe, and Mn are almost negligible except Cu.

• 대한방사선방어학회:학술대회논문집
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• 2011.04a
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• pp.106-107
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• 2011

• Transactions of the Korean Society of Mechanical Engineers B
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• v.35 no.12
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• pp.1317-1324
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• 2011

We propose a method operated in a vehicle to measure light absorption of particles in atmosphere. The advantage of this method is that it is insensitive to light scattering and hence can be used for the direct measurement of the light absorption coefficient without suffering from light scattering. With this method atmospheric light absorption can be measured at a time constant of 10 s. Further, our method allows for the real-time measurement of light absorption near a highway. The light absorption coefficients were high near a race track, an airport and the main gate where vehicles emitted carbonaceous particles.

• Proceedings of the Korean Vacuum Society Conference
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• 2016.02a
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• pp.86-86
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• 2016

최근 포항가속기연구소 10A 빔라인에 Scanning Transmission X-ray Microscopy (STXM)가 완성되어 운영 중이다. Soft x-ray imaging 장치로서 기술적으로 Sample scanning 기법이 활용된다. 이는 Zone plate를 통해 집속된 빔이 샘플에 조사되고 검출되는 방식이다. 이러한 Scanning 기법을 활용하고 있는 10A STXM은 기본적으로 흡수분광기법 (x-ray absorption spectroscopy)을 이용하고 있다. 특히, 10A 빔라인 STXM은 최고 20 nm까지 공간분해능이 가능하다는 장점이 있다. 따라서 수십에서 수백 나노미터 크기의 시료들 또는 나노구조에 대한 물리화학적 상태 분석이 쉽게 이루어지고 있다. 주로 시료를 투과하면서 흡수되는 X-선 세기 대비를 맵핑하는 형식의 이미지 데이터와 더불어 X-선의 에너지를 조정함으로써 각 에너지에 해당하는 이미지스택을 결과로 얻게 된다. 이러한 이미지 결과로부터 시료의 나노크기에서 오는 물리화학적 상태를 분석하고 물리에서 바이오까지 다양한 분야의 실험 활용이 가능한 상태다.

• Journal of ILASS-Korea
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• v.9 no.4
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• pp.67-76
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• 2004

Diode laser absorption sensors are advantageous because they may provide fast, sensitive, absolute, and selective measurements of species concentration. These systems are very attractive for practical applications owing to its compactness, reasonable cost, robustness, and ease of use. In addition, diode lasers we fiber-optic compatible and thus enable simultaneous measurements of multiple species along a line-of-sight. Recent advances of room-temperature, near-IR and visible diode laser sources for telecommunication, optical data storage applications make it possible to be applied for combustion diagnostics based on diode laser absorption spectroscopy. Therefore, combined with fiber-optics and high sensitive detection strategies, compact and portable sensor systems are now appearing for variety of applications. The objectives of this research are to develop new gas sensing system and to verify feasibility of this system. Wavelength modulation spectroscopy has been demonstrated in these experiments and has a bright prospect to this diode laser system.

• Journal of the Korean Chemical Society
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• v.44 no.3
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• pp.212-219
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• 2000

An absorption spectrometry coupled with flow injection analysis has been developed and tested for the analysis of the Cr$_2O_7^{2-}$/Nn$O_4^-$ mixtures. Even though one has to inject the sample twice into the FIA system and the process of the sample treatment is required to completely destroy the Mn$O_4^-$ ion for the analysis of the Cr$_2O_7^{2-}$ ion, the new method has definite advantages over the current method. It utilizes only a single analytical wavelength (570 nm) and enables one to construct calibration curves which accurately follow the Beer's law over wide ranges of analytical concentrations of both ions ($2.0{\times}10^{-6}$M∼$8.0{\times}10^{-3}$M for Cr$_2O_7^{2-}$ ion, $2.0{\times}10^{-6}$M∼$4.0{\times}10^{-3}$M for MnO4- ion).