• Journal of Astronomy and Space Sciences
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• v.24 no.1
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• pp.45-54
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• 2007

The relationship between the Galactic magnetic field strength and the gas density has been revisited. A synchrotron continuum emission data at 408 MHz and HI column density provide a good data for such study. But it is difficult to separate the synchrotron emission from the observed 408MHz radio emission, because the 408MHz radio emission has the component from the HI layer, as well as many components from other origins. We have tried to substract the component which is probably not related with HI layer, and present the results. We show that the method presented here is a more refined method than that of Brown & Chang (1983, hearafter BC83) to find the above mentioned relationship, and discuss the existence of such relationship in our Galaxy.

• Journal of The Korean Astronomical Society
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• v.40 no.4
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• pp.113-118
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• 2007

Recently far infra-red (FIR) polarization of the $850{\mu}m$ continuum emission from T Tauri disks has been detected. The observed degree of polarization is around 3 %. Since thermal emission from dust grains dominates the spectral energy distribution at the FIR regime, dust grains might be the cause of the polarization. We explore alignment of dust grains by radiative torque in T Tauri disks and provide predictions for polarized emission for disks viewed at different wavelengths and viewing angles. In the presence of magnetic field, these aligned grains produce polarized emission in infrared wavelengths. When we take a Mathis-Rumpl-Nordsieck-type distribution with maximum grain size of $500-1000{\mu}m$, the degree of polarization is around 2-3 % level at wavelengths larger than ${\sim}100{\mu}m$. Our study indicates that multifrequency infrared polarimetric studies of protostellar disks can provide good insights into the details of their magnetic structure.

• Journal of Power System Engineering
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• v.11 no.1
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• pp.45-50
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• 2007

Acoustic emission technology is applied to diagnosis the internal leak and operating conditions of the major valves at nuclear power plants. The purpose of this study is to verify availability of the acoustic emission as in-situ diagnosis method. In this study, acoustic emission tests are performed when the pressurized high temperature steam flowed through gate valve(1st stage reheater valve) and glove valve(main steam dump valve) on the normal size of 4 and 8". The valve internal leak diagnosis system for practical field was designed. The acoustic emission method was applied to the valves at the site, and the background noise was measured for the abnormal plant condition. To improve the reliability, a judgment of leak on the system was used various factors which are AE parameters, trend analysis, signal level analysis and RMS(root mean square) analysis of acoustic signal emitted from the valve operating condition internal leak.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.18 no.7
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• pp.563-570
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• 2006

We investigated the emission characteristics of gaseous organic contaminants from building materials and newly constructed apartments. The emission test for building materials was done with small chamber method, and field measurements in newly constructed apartment were carried out by Korea Standard Test Method for Indoor Air Quality. First, the emission test by small chamber showed that the TVOC emission from building materials was much higher than formaldehyde. On the other hand, as expected, considerably high concentration of both TVOC and HCHO was detected in the new apartment.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2013.05a
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• pp.111-112
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• 2013

Architecture has a large influence in the environment and human health. Therefore eco-friendly concept and sustainable development are important in Architectural field. This study aims to analyze impact of green building rating system on an apartment housing CO₂ emission using multiple regression analysis. But in this result, green building rating system has no effect on CO₂ emission. So, future study is required to analyze factors of green building rating system on the CO₂ emission.

• Journal of Practical Engineering Education
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• v.6 no.2
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• pp.127-134
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• 2014

Analyzing test data of a vehicle for evaluating its emission performance is an essential process in automotive development field, yet it is intricate and tedious task. In addition, clear understanding and care are required when the analysis process is carried out. Computer software solutions significantly reduce the time and the effort for such analysis. Developing a computer routine to analyze the emission data in a vehicle test demands a complete understanding of the emissions analysis and its related details. In this paper, the principals to develop a LabVIEW analysis routine (VI) are introduced helping automotive engineers comprehend the emission analysis process of a vehicle test data and instruct them to develop similar routines for such analysis.

• Journal of the Korean Society for Nondestructive Testing
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• v.23 no.3
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• pp.280-284
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• 2003

The field application of acoustic emission(AE) testing for brand-new metal pressure vessel were performed. We will introduce the test procedure for acoustic emission test such as instrument check distance between sensors, sensor location, whole system calibration, pressurization sequence, noise reduction and evaluation. The data of acoustic emission test contain many noise signal, these noise can be reduced by time filtering which based on the description of observation during AE test.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.37 no.1
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• pp.143-151
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• 2017

Recently Korea has presented carbon emission reduce goal of 37% compare to BAU until 2030 according to Paris Agreement in order to correspond to climate change. For this, researchers need to study positively on construction industry that emit $CO_2$ of $3^{rd}$ volume of 28 industry classification. This study calculated environmental load by LCA using the road part except tunnel and bridge among national road cases completed already. After selecting representative type of large construction type based on environmental emission, earth works, drainage works and paving works took up 84%. And this study analyzed the environmental emission feature of each detail construction type after selecting representative type each detail construction type. Utilization of each construction type emission attribute to environmental load during national road construction, will be helpful in making decision of eco-friendly national road construction based on environmental emission.

• Journal of the Korean Vacuum Society
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• v.16 no.4
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• pp.291-297
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• 2007

The field emission properties of CNT-emitters coated with Ag-Cu alloy have been investigated. The vertical aligned multi-walled CNTs were synthesized by dc-plasma enhanced chemical vapor deposition (dc-PECVD) and the Ag-Cu alloy was coated by using dc-magnetron sputter. The morphology of alloy-coated and un-coated CNT-emitters was observed by using SEM and their field emission properties were also measured. Annealing the AgCu-coated CNTs at temperature more than ${\sim}700^{\circ}C$, the Ag-Cu alloy was diffused to and aggregated on the top of the CNT as a Q-tip. A significant progress on the field emission was not observed with coating Ag-Cu alloy on the CNTs, but a certain improvement in a resistance against oxygen gas was made confirmation. It seems to be due to inertness of Ag-Cu alloy on the CNTs.

• Journal of the Korean Vacuum Society
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• v.17 no.4
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• pp.365-373
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• 2008

We have succeeded in synthesizing vertically aligned thin multi-walled carbon nanotubes (VA thin-MWCNTs) by a catalytic chemical vapor deposition (CCVD) method onto Fe/Al thin film deposited on a Si wafers using an optimum amount of hydrogen sulfide ($H_2S$) additive. Scanning electron microscope (SEM) images revealed that the as-synthesized CNT arrays were vertically well-oriented perpendicular to the substrate with relatively uniform length. Transmission electron microscope (TEM) observations indicated that the as-grown CNTs were nearly catalyst-free thin-MWCNTs with small outer diameters of less than 10nm. The average wall number is about 5. We suggested a possible growth mechanism of the VA thin-MWCNT arrays. The VA thin-MWCNTs showed a low turn-on electric field of about $1.1\;V/{\mu}m$ at a current density of $0.1\;{\mu}A/cm^2$ and a high emission current density about $2.5\;mA/cm^2$ at a bias field of $2.7\;V/{\mu}m$. Moreover, the VA thin-MWCNTs presented better field emission stability without degradation over 20 hours (h) at the emission current density of about $1\;mA/cm^2$.