• Journal of the Korean Institute of Gas
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• v.22 no.6
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• pp.28-33
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• 2018

Currently, the government has been expanding the supply of semi-low-pressure in order to solve the problems of unsupplied area of city gas and to secure the economical efficiency of small supplied area. It is mainly supplied from the central storage tank to each household by buried piping. It is necessary to provide such a shutoff valve that can block the excess flow gas due to pipeline leak or rupture when piping is damaged by other construction. For this study, System CFD code named Flownex has been used and a component corresponding to the actual EFV was developed. We compared Flownex results with experimental data to verify the accuracy of Flownex and confirmed the error rate to be around 2%. In this study, pipeline network modeling was done by selecting the LPG supply pipeline in a village and installed the component of the EFV at each junction. We selected the longest pipeline from the main pipeline and set scenarios so that the excess flow occurs by that the pipeline is ruptured before entering the household. The excess flow occurs by the pipeline rupture and the EFV is closed. At this time, we analyzed backflow effects to the other pipeline by closing EFV.

• Journal of Hydrogen and New Energy
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• v.33 no.4
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• pp.284-292
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• 2022

Hydrogen is promising a candidate for energy supporting the carbon neutrality policy for greenhouse gas reduction, which is being promoted in several countries, including Korea. Although challenging efforts-such as lowering the costs of green hydrogen production and fuel cells-remain, hydrogen fuel cell electric vehicles (FCEVs) are expected to play a significant role in the energy transition from fossil fuels to renewable energy. In line with this objective, the hydrogen FCEV working group in the International Organization for Standardization (ISO) compiled and revised international standards related to hydrogen refueling stations as of 2019. A well-established hydrogen quality management system based on the standard documents will increase the reliability of hydrogen charging stations and accelerate the use of FCEVs. In this study, among the published ISO standards and other references, the main requirements for managing charging stations and developing related techniques were summarized and explained. To respond preemptively to the growing FCEV market, a continuous hydrogen quality monitoring method suitable for use at hydrogen charging stations was proposed.

• Journal of Korea Soil Environment Society
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• v.4 no.3
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• pp.45-56
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• 1999

A biofilter was established to remove the ammonia, which is representative nitrogen-contained malodorous gas. in a compost factory. Removal efficiency of ammonia and hydrogen sulfide also was investigated. A quantity of malodor gas produced in a compost factory was affected greatly by the weather. compost states and working condition of a fertilizing mixer, and the produced gas concentrations doubled by above various parameters. By operating a water scrubbing system for removing water-soluble malodorous gases effectively. we could improve the removal efficiency over three times. We investigated long-term stability of biofilter under continuous gas flow(SV=500h-1) for 100 days. The results showed 30 days of microbial retention time. After the days, deodorization efficiency of biofilter was kept steady state. and the removal efficiency was kept over 95% for ammonia and 97% for hydrogen so]fide. respectively. The electric consumption of the biofilter, which could treat malodorous gas of 100$\textrm{m}^3$/min, applied in the compost factory was evaluated about 80u0day and water consumption was 80~100$\ell$/day. These results concluded that the biofilter is a excellent deodorization technology as well as cost-effective for removing malodorous gas produced in a compost factory.

• Journal of the Korean Institute of Gas
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• v.18 no.6
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• pp.7-13
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• 2014

As the interest on the air pollution is gradually rising up at home and abroad, automotive and fuel researchers have been working on the exhaust emission reduction from vehicles through a lot of approaches, which consist of new engine design, innovative after-treatment systems, using clean (eco-friendly alternative) fuels and fuel quality improvement. This research has brought forward various main issues : whether PM emissions should be regulated for diesel and gasoline vehicles and whether gasoline and LPG powered vehicles can be further neglected from PM emission inventories. Finally, the greenhouse gas ($CO_2$, $CH_4$, $N_2O$) regulation has been discussed including automotive emission regulation. The greenhouse gas and emissions (PM) particle of automotive had many problem that cause of ambient pollution, health effects. This paper discussed the influence of LPG fuel on automotive cold startability and exhaust emissions gas. Also, this paper assessed emission characteristics due to the test temperature. These test temperature were performed by dividing the temperature of the test mode and the lowest local temperature in winter. Through this study, the correlation of cold startability, exhaust emission and greenhouse gas emission was analyzed.

• Proceedings of the Korean Vacuum Society Conference
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• 2015.08a
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• pp.181.2-181.2
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• 2015

Sputtering is one of the most popular physical deposition methods due to their versatility and reproducibility. Synthesis of Cr thin films by DC magnetron sputtering using glancing angle deposition (GLAD) has been reported. Chromium thin films have been prepared at two different working pressure($2.0{\times}10-2$, 30, $3.3{\times}10-3torr$) on Si-wafer substrate using magnetron sputtering with glancing angle deposition (GLAD) technique. The thickness of Cr thin films on the substrate was adjusted about 1 mm. The electrical property was measured by four-point probe method. For the measurement of density in the films, an X-ray reflectivity (XRR) was carried out. The sheet resistance and column angle increased with the increase of glancing angle. However, nanohardness and density of Cr thin films decreased as the glancing angle increased. The measured density for the Cr thin films decreased from 6.1 to 3.8 g/cc as the glancing angle increased from $0^{\circ}$ to $90^{\circ}$ degree. The low density of Cr thin films is resulted from the isolated columnar structure of samples. The evolution of the isolated columnar structure was enhanced at the conditions of low sputter pressure and high glancing angle. This GLAD technique can be potentially applied to the synthesis of thin films requiring porous and uniform coating such as thin film catalysts or gas sensors.

• Proceedings of the KIEE Conference
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• 2003.10a
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• pp.322-325
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• 2003

BST thin films were etched with inductively coupled plasmas. A chemically assisted physical etch of BST was experimentally confirmed by ICP under various gas mixtures. After a 20 % addition of $BCl_3$ to the $Cl_2/Ar$ mixture, resulting in an increased the chemical effect. As a increases of RF power, substrate power, and substrate temperature, and decrease of working pressure, the ion energy flux and chlorine atoms density increased. The maximum etch rate of the BST thin films was 90.1 nm/min at the RF power, substrate power, working pressure, and substrate temperature were 700 W, 300 W, 1.6 Pa, and 20 $^{\circ}C$, respectively. It was proposed that sputter etching is dominant etching mechanism while the contribution of chemical reaction is relatively low due to low volatility of etching product.

• Journal of Korean Public Health Nursing
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• v.9 no.2
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• pp.43-51
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• 1995

Many poeple has been engaged in industry is aware of the dangers from exposure to high intensity nose levels. The exposure to high intensity noise is encountered in a large number of situations. Laws governing the safety and health of employed people being to create a suitable working environment and eliminate unsafety practices and processes. Work areas should be designed and laid out so that they are satisfactory both from the environmental and safety points of view. In this connection safety also implies that noise is kept at a level which is not likety to cause hearing damage. This study was performed to measure the noise of press and assembly process in an automobile factory. and suggested the method of noise control. Consequently the effect ways of reducing level in working environment are as follows; 1. Changes to machines which would reduce noise generation. 2. Alteration of equipment to avoid impact in machinery and handing materials. 3. Enclosure of noisy machines or machine parts. 4. Mounting of attenuators on gas and air outlets as well as ventilation ducts. 5. Erection of sound absorbing screens. linings. and baffles in work areas. 6. The personal ear protectors can be chosen to protect the workers.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2002.07a
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• pp.22-25
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• 2002

In this paper, we deposited MgO buffer layer on p-type (100)Si substrate in the condition of substrate temperature 400$^{\circ}C$, working gas ratio Ar:O$_2$=80:20, RF Power 50W, working pressure 10mtorr, and the thickness of the film was about 300${\AA}$. Then we deposited Ba$\sub$0.5/Sr$\sub$0.5/TiO$_3$ thin film using RF Magnetron sputtering method on the MgO/Si substrate in various RF power of 25W, 50W, 75W. The film deposited in 50W showed the best crystalline from the XRD measurement. To know the electrical properties of the film, we manufactured Al/BSTMgO(300${\AA}$)/Si/Al structure capacitor. In the result of I-V measurement, The leakage current density of the capacitor was lower than 10$\^$-7/A/$\textrm{cm}^2$ at the range of ${\pm}$150kV/cm. From C-V characteristics of the capacitor, can calculate the dielectric constant and it was 305. Finally we deposited BST thin film on bare Si substrate and (100)MgO substrate in the same deposition condition. From the comparate of the properties of these samples, we found the properties of BST thin film which deposited on MgO/Si substrate were better than on bare Si substrate and similar to on MgO substrate.

• Journal of Korean Society of Occupational and Environmental Hygiene
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• v.3 no.2
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• pp.213-226
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• 1993

The purpose of this study is to computerize the design of single source for a duct work system which is essential for the improvement of working places. There are different types of hood, such as general hood, push pull hood and canopy hood. And out of these three types, general hood and canopy hood were used as subjects of this study. The software used here was Quattro Pro 123 programm, and the hardware was IBM PS/SX(type 5510-SK4 S/N 83-05164). And the results are tabulated in