• Journal of the Korean Institute of Gas
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• v.19 no.3
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• pp.38-43
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• 2015

For buried gas pipelines, cathodic protection system shall be installed to protect against corrosion. The surveys of pipe-to-soil potentials for the gas pipelines should be carried out at the test box more than once a year. In urban, the test box is usually located on the driveway, therefore, it is difficult to measure the potentials. That is, traffic control is needed when carrying out the measurements of the potentials on daytime, or measurements of pipe-to-soil potentials at the test box located on the driveway have to be carried out in the late night when the traffic is light. We have developed remote potential monitoring system using the solid reference electrode and the wireless communication technology for the purpose of removing above problems. We have installed the developed solid reference electrodes at a site and monitored the potentials by wireless communication. Measured potential values were transferred to the server in office and analyzed. We have found the pipe-to-soil potentials transferred to the web server make no difference to the potentials measured directly on the site.

• Analytical Science and Technology
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• v.30 no.5
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• pp.240-251
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• 2017

1,1,1,2-Tetrafluoroethane (HFC-134a), which is used as refrigerant in air conditioners, has been recently regulated as a greenhouse gas and is recommended for reuse by refining. It is very important to quantitatively analyze trace impurities present in the refrigerant to evaluate the criteria for reuse. In this study, trace impurities including C, H, Cl, and F, which are difficult to quantify because there are no reference materials, were quantitatively analyzed by a gas chromatograph-atomic emission detector (GC/AED); for this analysis, this was preceded by a qualitative analysis with a GC-mass selective detector (GC/MSD). In addition, the AED response was investigated using a hydrocarbon mixed reference material, which was proportional to the number of atoms in the component. Fifteen refrigerant components were detected as trace impurities in HFC-134a by qualitative analysis of trace impurities including C, H, Cl, and F in the samples. Based on the results of the qualitative analysis, quantitative analysis of trace impurities using AED showed that the highest mole fractions were for the $CHClF_2$ component ($45438.38{\mu}mol/mol$) in one sample and for the $C_2H_2ClF_3$ component ($1311.47{\mu}mol/mol$) in another sample. From this study, it has been shown that it is possible for this analytical method to be applied to the qualitative and quantitative analysis of trace compounds in refrigerants, which are difficult to quantify because of the absence of reference materials.

• Journal of Sensor Science and Technology
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• v.25 no.5
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• pp.377-381
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• 2016

NDIR $CO_2$ gas sensor was prototyped with ASIC implemented thermopile sensor which included temperature sensor and White-Cell structure in this paper. The temperature dependency of dual infrared sensors ($CO_2$ and reference IR sensors) has been characterized and their output voltage ratios according to the temperature and gas concentration were presented in this paper for achieving temperature compensation algorithm. The initial output voltages of NDIR $CO_2$ gas and reference IR sensors showed $3^{rd}$ order polynomial and linear output voltages according to the variation of ambient temperatures from 253 K to 333 K, respectively. The output voltages of temperature sensor presented a linear dependency according to the ambient temperature and could be described with V(T) = -3.0069+0.0145T(V). The characteristics of output voltage ratios could be modeled with five parameters which are dependent upon the ambient temperatures and gas concentration. The estimated $CO_2$ concentrations showed relatively high error below 300 ppm (maximum 572 % at 7 ppm $CO_2$ concentration), however, as the concentration increased from 500 ppm to 2,000 ppm, the overall estimated errors of $CO_2$ concentrations were less than ${\pm}10%$ in this research.

• The Bulletin of The Korean Astronomical Society
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• v.39 no.1
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• pp.43.2-43.2
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• 2014

We investigate the ionized gas kinematics at the center of 6 nearby Seyfert galaxies, using the integral field spectroscopy data from the Calar Alto Legacy Integral Field spectroscopy Area survey Data Release 1. To understand the kinematic nature of the ionized gas in the narrow-line regions (NLRs), we measured the flux, velocity, and velocity dispersion of the [OIII] $5007{\AA}$ and Ha $6563{\AA}$ emission lines, after subtracting a best-fit stellar population model representing the stellar features. At the same time, we measured stellar velocity as a reference for the systemic velocity, and stellar velocity dispersion. We spatially resolved the velocity structure of the ionized gas using each emission line and compared it to that of stars. In this poster we present the flux, velocity, and velocity dispersion maps of the ionized gas and stars, and discuss the nature of the ionized gas outflows in the central kiloparsec scale.

• Analytical Science and Technology
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• v.35 no.6
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• pp.249-255
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• 2022

In this study, a new method for the analysis of high-purity nitrogen was developed. A gas chromatography-flame ionization detector (GC-FID) was used for purity analysis. Certified reference materials (CRMs) at a level of 3 µmol/mol of carbon monoxide (CO), carbon dioxide (CO₂), and methane (CH₄), which may exist in high-purity nitrogen, were prepared using the gravimetric method, and these CRMs were used for purity analysis. In this new method, ultra-high-purity and high-purity nitrogen were used as carrier gases. The impurities in high-purity nitrogen were quantitatively analyzed by comparing the differences in the area values of the GC chromatograms of the prepared CRMs. We purchased liquid nitrogen and three bottles of nitrogen gas, which were produced by three different manufacturers, using high-purity nitrogen. Furthermore, to validate the developed purity analysis method, the fraction of impurities in high-purity nitrogen was compared with the results of the typical purity analysis method. The comparison results were consistent within the expanded uncertainties (k = 2).

• Analytical Science and Technology
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• v.35 no.5
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• pp.205-211
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• 2022

Deuterium (D) is an isotope with one more neutron number than hydrogen (H). Heavy elements rarely change their chemical properties with little effect even if the number of neutrons increases, but low-mass elements change their vibration energy, diffusion rate, and reaction rate because the effect cannot be ignored, which is called an isotope effect. Recently, in the semiconductor and display industries, there is a trend to replace hydrogen gas (H₂) with deuterium gas (D₂) in order to improve process stability and product quality by using the isotope effect. In addition, as the demand for D₂ in industries increases, domestic gas producers are making efforts to produce and supply D₂ on their own. In the case of high purity D₂, most of them are produced by electrolysis of heavy water (D₂O), and among D₂, hydrogen deuteride (HD) molecules are present as isotope impurities. Therefore, in order to maximize the isotope effect of hydrogen in the electronic industry, HD, which is an isotope impurity of D₂ used in the process, should be small amount. To this end, purity analysis of D₂ for industrial processing is essential. In this study, HD quantitative analysis of D₂ for high purity D₂ purity analysis was established and hydrogen isotope RM (Reference material) was developed. Since hydrogen isotopes are difficult to analyze with general gas analysis instrument, they were analyzed using a high-precision mass spectrometer (Gas/MS, Finnigan MAT271). High purity HD gas was injected into Gas/MS, sensitivity was determined by a signal according to pressure, and HD concentrations in two bottles of D₂ were quantified using the corresponding sensitivity. The amount fraction of HD in each D₂ was (4518 ± 275) μmol/mol, (2282 ± 144) μmol/mol. D₂, which quantifies HD amount using the developed quantitative analysis method, will be manufactured with hydrogen isotope RM and distributed for quality management and maintenance of electronic industries and gas producers in the future.

• Proceedings of the KIEE Conference
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• 2005.11a
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• pp.145-147
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• 2005

In present, most of metallic structures(gas pipeline, oil pipeline, water pipeline, etc) are running parallel with subway and power line in seoul. Moreover subway system and power line make a stray current due to electrical corrosion on metallic structures. The owner of metallic structures has a burden of responsibility for the protection of corrosion and the prevention against big accident such as gas explosion or soil pollution and so on. So, they have to measure and analyze the data about P/S(Pipe to Soil) potential due to stray current of subway system. So, we have developed the Real-time Wireless Remote Monitoring System for Stray Current of Subway System. In this system, the permanent buried type reference electrode is necessary. In this paper, results of development of buried type reference electrode using porous ceramic$({\alpha}-Al_{2}O_{3})$ are presented.

• Journal of the Korean Institute of Gas
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• v.16 no.4
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• pp.23-31
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• 2012

The basic understanding of gas diffusion and technology to predict the diffusion phenomena are needed to prepare against a disaster of leakage of natural gas and to design better consistent and reliable gas supply system in enclosure. The experimental results of British Gas Technology Co. are used in present study as a reference of theoretical study using CFD. The present results of 2D CFD analysis for mass flow rate of nozzle release show good agreement with experimental results within 2.6 % error. 3D CFD analysis for the characteristics of natural gas diffusion in enclosure with various ventilation patterns also gives reasonable agreement with experimental results.

• Nuclear Engineering and Technology
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• v.38 no.2
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• pp.129-138
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• 2006

The Gas-cooled Fast Reactor (GFR) is one of the six reactor concepts selected within the framework of the Generation IV initiative and is the reference concept for the Commissariat $\grave{a}$ l'Energie Atomique $(CEA^1)$. Two reactor unit sizes have been considered: 600 MWth and 2400 MWth. As far as thermal-hydraulics is concerned, reactor decay heat removal (DHR) proves to be a major issue. The CEA has conducted exploratory design studies to address this issue and a reference solution for the 600MWth reactor has been recommended.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.20 no.3
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• pp.273-280
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• 2007

In this paper, the ZnO surge arrester performance of power distribution class has been studied under different manufacturing conditions such as housing materials(polymeric, porcelain), interface sealants and one-body molding type. In the recent years, the polymeric ZnO surge arresters have been developed and put into operations based on their excellent characteristics. For polymeric surge arresters, the inner gas volume is extremely small, especially in solid insulation polymeric arresters there are not any gas volume inside arresters in the structure due to polymeric materials are filled into the internal gas volume. The sealing integrity is related to safe operation of surge arrester, the prime failure reason of porcelain housed arresters is moisture ingress. In this paper, the sealing integrity of polymeric surge arresters is investigated with moisture multi-aging test and ingress test. The evaluation techniques are used to inspect the sealing integrity of polymeric arresters, including leakage current, surface temperature, reference voltage and dissipation factor.