• Journal of the Korean Vacuum Society
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• v.1 no.1
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• pp.1-10
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• 1992

Three chemical precleaning methods-degreasing, electropolishing and acidic etching-suitable for stainless steel vacuum chamber have been studied and compared. The techniques used in evaluating and comparing the three treatments include Auger analysis and the measurement of the outgassing rate. The obtained outgassing rates (N2 equivalent) are 1.1 $\times$ 10-10torr l/s cm2 and 3.9 $\times$ 10-11torr l/s cm2 for degreasing electropolishing, and etching method, respectively, after 48 hours from the initial pumpdown at room temperature. A simple model is introduced to analyze the pumpdown curve. Some surface parameters, such as surface coverage, mean residence time, and desorption energy, are calculated from corresponding equations derived from this model.

• Journal of Information Technology Services
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• v.12 no.2
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• pp.361-371
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• 2013

Public domain defect data sets, such as NASA data sets which are available from the NASA MDP and PROMISE repositories, make it possible to compare the results of different defect prediction models by using the same data sets. This means that repeatable and general prediction models can be built. However, some recent studies have raised questions about the quality of two versions of NASA data set, and made new cleaned data sets by applying their data cleaning processes. We find that there are two ways in the NASA MDP versions to determine the defectiveness of a module, 0 or 1, and the two results are different in some cases. This serious problem, to our knowledge, has not been addressed in previous studies. To handle this ambiguity problem, we define two kinds of module defectiveness and two conditions that can be used to determine the ambiguous cases. We meticulously analyze 5 projects among the 13 NASA projects by using our ambiguity analysis method. The results show that JM1 and PC4 are the best projects with few ambiguous cases.

• Special Issue of the Society of Naval Architects of Korea
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• 2005.06a
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• pp.198-205
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• 2005

Reduction of labor hour for cleaning up of the used abrasives after blasting. is attempted by improving the efficiency of abrasive recovery process in the protective coating of ship's block, For this purpose, the theoretical background for pneumatic transport technology in the abrasive recovery system as well as experimental evaluation on the effect of design parameters such as flow pattern, saltation velocity and pressure drop on the efficiency of the abrasive recovery system are employed . By optimizing the operating parameters such as the length and diameter of the suction hose, specification of recovery device and recovery mouth, a new method which can dramatically increase the efficiency of abrasive recovery system, is proposed.

• Proceedings of the KSR Conference
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• 2008.06a
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• pp.1486-1493
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• 2008

In this paper, we performed analysis and comparison on emergency response action for passengers, drivers, workers and controllers in case of failure occurrence on rail infrastructure and rolling stock. In general, the subjects of emergency response action perform the response action with following emergency response procedures when accidents occurred. In reality, however, no matter how well the subjects are trained, it is hard to follow the emergency response procedures precisely without making any mistakes. As for emergency response action, the most significant factor for the subjects is to follow the emergency response procedures as learned, without any hesitation. In this paper, therefore, we analyzed the emergency response actions that should be performed by passengers and railway workers when emergency accidents occurred. We also examined the communication facilities for emergency response among train, wayside and station in order to provide the emergency reporting system for passenger and the method for cleaning out the accident area.

• Proceedings of the Korean Vacuum Society Conference
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• 2011.08a
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• pp.380-380
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• 2011

ZnO nanorod (NR) arrays prepared via simple ammonia hydrothermal method exhibiting superhydrophilicity, high transmittance and antireflection. These properties result from the unique surface structure and material property of ZnO NR arrays. Highly rough surface due to ZnO NRs enhanced hydrophobicity/hydrophilicity of the films and short NRs (about 300 nm) made ZnO arrays transparent. ZnO NR films were chemically modified by dipping the sample into 5mM stearic acid/ethanol solution for 3 hours. Then the ZnO NRs became superhydrophobic surfaces, whose contact angle reached 159.2$^{\circ}$ maintaining their high transmittance. These biomimetic ZnO NR arrays can be used in diverse field, such as antifogging/self-cleaning surfaces and optical devices.

• Journal of the Korean Solar Energy Society
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• v.35 no.2
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• pp.63-71
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• 2015

Soiling is the accumulation of dirt on photovoltaic (PV) modules and can reduce the performance of the PV power plant depending on the site location. Nevertheless, the reason which can not be the great interest to researchers of PV reliability is the phenomenon of performance loss caused by external environmental factors, not the internal degradation of the PV module. In this paper, we provide the phenomenon, history, research overview and mitigation method in order to help understanding of the soiling.

• Journal of the Semiconductor & Display Technology
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• v.7 no.2
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• pp.35-38
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• 2008

This study shows the improvement of PR-Ashing rates in semi-conductor process using Atmospheric Plasma. Taguchi method is used to improve Ashing rates of photo-resist that is spread on the surface of a wafer. Improvement of Ashing rates is acquired through the decision of the effective factors and suitable combination of the factors. The results show the contribution rate of each factor and the effectiveness of Plasma for PR-Ashing process in this system.

• Proceedings of the Korean Vacuum Society Conference
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• 1993.07a
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• pp.39-39
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• 1993

A finite element analysis and Monte Carlo method have been applied to calculate the ppressure pprofiles around the ppohang Light Source (ppLS) electron storage ring with the aim of ppredicting the pperformance of the vacuum system designed for the ppLS vacuum system. After ppropperly choosing the design pparameters, the ppressure distribution are calculated as a function of the integrated stored beam current [AmppHrs]. The effect of changes of the vacuum pparameters, such as installed ppumpping sppeeds and synchrotron radiation induced gas desorpption rates on the ppressure pprofile, is also studied. The results indicate that the use of lumpped non-evapporable getter ppumpps together with spputter ion ppumpps for ppumpping the ppLS down to the required ppressure is ppossible in the ppresence of synchrotron induced gas loads, after resonable beam cleaning time.

• International Journal of Fuzzy Logic and Intelligent Systems
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• v.9 no.4
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• pp.315-320
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• 2009

The popularity of autonomous mobile robots have been rapidly increasing due to their new emerging application areas, from room cleaning, tourist guidance to space explorations. However, the development of a satisfactory control algorithm that will enable the autonomous mobile robots to navigate safely especially in dynamic environments is still an open research problem. In this paper, a newly proposed potential field based control method is implemented, analyzed, and improvements are suggested based on experimental results obtained from simulations. The experimental results are presented to show the effectiveness of the behavior-based control using the proposed potential field generation technique.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2001.11a
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• pp.189-192
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• 2001

Recently, STI process is getting attention as a necessary technology for making high density of semiconductor by devices isolation method. However, it does have various problems caused by CMP process, such as torn oxide defects, nitride residues on oxide, damages of si active region, contaminations due to post-CMP cleaning, difficulty of accurate end point detection in CMP process, etc. In this work, the various defects induced by CMP process was introduced and the above mentioned Problems of CMP process was examined in detail. Finally, the guideline of future CMP process was presented to reduce the effects of these defects.