• Journal of the Korean Institute of Gas
• /
• v.25 no.6
• /
• pp.53-65
• /
• 2021

While the hydrogen refueling station is rapidly expanded and installed, the safety inspection of the hydrogen pressure vessel in the station should be very important. Of these, according to ASME, hydrogen embrittlement tests must be performed for hydrogen vessel that store hydrogen above a certain pressure. The main test method for hydrogen embrittlement inspection is to carry out fracture tests and fatigue fracture tests in a high pressure hydrogen atmosphere, which allows the durability limit of the pressure vessel to be measured and the endurable limit to be determined in the hydrogen atmosphere. In detail, the critical crack depth can be calculated by the stress intensity factor(K), and the service life can be determined by da/dN (fatigue growth rate). API579-1/ ASME FFS-1 part 9 exemplifies the calculation method according to the mode of crack-like flaws, but for various shapes such as plates and cylinders, there are about 55 modes according to the shape and location of the crack. Due to the fairly complex formula, it is not easily accessible. In this study, we will show you how to calculate fracture mechanics numerically via Excel and VBA. In addition, this was applied to analyze the effects of the thickness and inner diameter of the pressure vessel on the service life.

• Journal of Sensor Science and Technology
• /
• v.6 no.4
• /
• pp.265-273
• /
• 1997

The TMA gas sensors are fabricated with the ZnO-based thin films grown by a RF magnetron sputtering method. We investigate the surface carrier concentration, Hall electron mobility, electrical resistivity and sensitivity according to temperature variation and TMA gas concentration. The ZnO-based thin film sensors prepared by sputtering in oxygen showed higher surface carrier concentration, higher Hall mobility, higher sensitivity, and lower electrical resistivity than sensors prepared by sputtering in argon. The doping ZnO-based thin film sensors showed the same electrical properties in comparison with nondoping sensors. In case of sputtering on the oxygen gaseous atmosphere, the ZnO-based thin film sensors doped with 4.0 wt.% $Al_{2}O_{3}$, 1.0 wt.% $TiO_{2}$, and 0.2 wt.% $V_{2}O_{3}$ showed the highest surface carrier concentration of $5.95{\times}10^{20}cm^{-3}$, Hall electron mobility of $177\;cm^{2}/V{\cdot}s$, lowest electrical resistivity of $0.59{\times}10^{-4}{\Omega}{\cdot}cm$ and highest sensitivity of 12.1(working temperature, $300^{\circ}C$, TMA gas, 8 ppm).

• Journal of Sensor Science and Technology
• /
• v.9 no.1
• /
• pp.36-43
• /
• 2000

In oder to enhance the selectivity of TMA(trimethylamine) gas, the ZnO-based films which were doped with $Al_2O_3$, $TiO_2, $In_2O_3$ and $V_2O_5$ catalysts with various weight percents were deposited in oxygen by RF magnetron sputtering method. To improve electrical stability of sensors, the ZnO-based films were annealed in oxygen at $700^{\circ}C$ for 1 hour. The TMA selectivity of sensors was defined by the magnitude($S_{TMA}/S_{DMA}$ and $S_{TMA}/S_{NH3}$) of TMA sensitivity relative to DMA and sensitivity ammonia($NH_3$) sensitivity, respectively. The $ZnO+Al_2O_3(4\;wt.%)+TiO_2(1\;wt.%)+In_2O_3(1\;wt.%)$ sensor showed high $S_{TMA}/S_{DMA}$ of 5.9 and $S_{TMA}/S_{NH3}$ of 26 to 160 ppm at the working temperature of $300^{\circ}C$ respectively.

• Proceedings of the Korean Vacuum Society Conference
• /
• 2007.02a
• /
• pp.155-155
• /
• 2007

• Proceedings of the Korean Institute of Surface Engineering Conference
• /
• 2006.04a
• /
• pp.103-103
• /
• 2006

• Proceedings of the Materials Research Society of Korea Conference
• /
• 2007.11a
• /
• pp.135.2-135.2
• /
• 2007

• Journal of the Korean Ceramic Society
• /
• v.31 no.11
• /
• pp.1369-1377
• /
• 1994

• Proceedings of the Korean Institute of Surface Engineering Conference
• /
• 2005.11a
• /
• pp.170-170
• /
• 2005

• Proceedings of the Korean Radioactive Waste Society Conference
• /
• 2015.10a
• /
• pp.279-280
• /
• 2015

• Proceedings of the Korean Radioactive Waste Society Conference
• /
• 2016.05a
• /
• pp.85-86
• /
• 2016