• Bulletin of the Korean Chemical Society
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• v.22 no.1
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• pp.63-67
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• 2001

The photophysical properties and the singlet oxygen generation efficiency of tetrathiarubyrin have been investigated to elucidate the possibility of its use as a photodynamic therapy (PDT) photosensitizer by steady-state and time-resolved spectroscopic methods. The observed photophysical properties were affected by various molecular aspects, such as extended ${\pi}conjugation$, structural distortion, and internal heavy atom. The steady-state electronic absorption spectrum was red-shifted due to the extended $\pi-conjugation$, and the spin orbital coupling was enhanced by the structural distortion and the internal heavy atom effect. As a result of the enhanced spin orbital coupling, the triplet quantum yield increased to 0.90 $\pm$ 0.10 and the triplet state lifetime was shortened to 7.0 $\pm$ 1.2 ${\mu}s$. Since the triplet state decays at a relatively faster rate, the efficiency of the oxygen quenching of the triplet state decreases. The singlet oxygen quantum yield was estimated to be 0.52 $\pm$ 0.02, which is somewhat lower than expected. On the other hand, the efficiency of singlet oxygen generation during the oxygen quenching of triplet state, $f{\Delta}^T$, is near unity. Such high efficiency of singlet oxygen generation can be explained by the following two possible factors: The hydrogen bonding of ethanol which impedes the deactivation pathway of the charge transfer complex with oxygen to the ground state, the less probability of the aggregation formation.

• Proceedings of the KSME Conference
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• 2007.05a
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• pp.688-693
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• 2007

Most frame structures cannot be manufactured in a single-piece form. Ideally, when a structure is built up by assembling multi pieces, assembly at the joints should be rigidly performed enough to have almost full stiffness, which is difficult for practical reasons such as manufacturing cost and time. In this research, we aim to develop a manufacturability-oriented compliance-minimizing topology optimization using a ground beam model incorporating additional zero-length elastic joint elements. In the present formulation, design variables control the stiffness of zero-length elastic joints, not the stiffness of beams. Because joint stiffness values at the converged state can be utilized to select candidate assembly locations and their strengths, the technique is extremely useful to design multi-piece frame structures. An optimal layout is also extracted based on the stiffness values.

• Proceedings of the Korean Geotechical Society Conference
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• 2004.03b
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• pp.181-188
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• 2004

Composite soil methods among granular pile merhods that we could improve soft ground of fine soil particles by, have permeability as one of fundamental principals. The catual state, that voids of sand or gravel, etc. of granular soil as drainage materials are clogged by fine soil particles, is 'clogging'. In this study, it is analysed that using sand or gravel, etc. of granular soil as drainage materials, experiment are made by clogging tester on several condition.

• Journal of Environmental Science International
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• v.5 no.6
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• pp.727-738
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• 1996

An one dimensional atmosphere-canopy-soil interaction model is developed to estimate of the heat budget parameter in the atmospheric boundary layer. The canopy model is composed of the three balance equations of energy, temperature, moisture at ground surface and canopy layer with three independent variables of Tf(foliage temperature), Tg(ground temperature), and qg(ground specific humidity). The model was verilied by comparative study with OSUID(Oregon State University One Dimensional Model) proved in HAPEX-MOBILHY experiment. Also we applied this model in two dimensional land-sea breeze circulation. According to the results of this study, surface characteristics considering canopy acted importantly upon the simulation of meso-scale circulation. The factors which used in the numerical experiment are as follows ; the change for a sort of soil(sand and peat), the change for shielding factor, and the change for a kind of vegetation.

• Proceedings of the KSR Conference
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• 2007.05a
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• pp.1619-1625
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• 2007

This paper deals with the heat transfer characteristics due to a fire of train standing at under-ground station. In order to analyze the fluid characteristics at under-ground station, the governing equation was assumed to be steady-state, incompressible and turbulent fluid model. The commercial Fluent ver. 6.0 was used to solve the above numerical problem. Through the numerical analysis, fluid path-line, temperature distribution and $CO_2$ density distribution are demonstrated for three kinds of cases. As a conclusion of the study, a scenario for operation of ventilation fan in a fire is proposed.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.2 no.2
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• pp.5-13
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• 2003

In this study, experiments of high speed grinding had been earned out in a STD11 specimen for evaluating the grindability with designed CBN grinding wheels Ground surfaces were analyzed and evaluated by means of surface Integrities and wheel damages. The surface roughness and 3 dimensional profile had been used for analyzing the micro-surface integrity. The residual stress of the ground surface had been measured by the x-ray diffraction method. Also, the surface state of the ground specimens and the grinding wheels were evaluated by a metallurgical microscope and SEM system after high speed grinding in order to choose the suitable machining conditions.

• Economic and Environmental Geology
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• v.32 no.2
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• pp.169-175
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• 1999

The water leakage of reservoir embankment usually occurs through water vein, which gives little influence on the embankment in a normal state. However, the embankment can be destroyed when the water level of reservoir increases with heavy rain in summer. Investigating the water vein and its path is therefore very important from the viewpoint of disater prevention and embankment protection. This paper presents survey results of one-meter-depth ground temperature and multi-point temperature logging in an embankment in Japan to delineate water veins and permeable formations. Four water veins have been predicted in the embankment by comparing measured one-meter-depth ground temperatures with the background ones which have no effect of water vein. The multi-point temperature logging was carried out in the borehole drilled at one of the predicted water veins. Depth and thickness of the permeable formation in the borehole can be determined from temperature restoration ratios with elapsed time. From these results we can find that the water leakage of reservoir embankment mainly occurs in sandy soil formation in the embankment.

• Nuclear Engineering and Technology
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• v.43 no.1
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• pp.7-12
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• 2011

In this paper we review the neutron scattering work performed on 3 different antiferromagnetic pyrochlores which reveal how the character of the magnetic interactions plays a major role on the eventual outcome of the magnetic ground state. $Tb_2Ti_2O_7$, $Er_2Ti_2O_7$ and $Y_2Mo_2O_7$ have all been extensively studied over the past 15 years and are known to display, respectively, spin liquid, long range ordered and glassy ground states. Although detailed experiments have been performed on these compounds, and much is known about their low temperature properties, a detailed theoretical understanding of their ground states remains elusive.

• Journal of Institute of Control, Robotics and Systems
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• v.16 no.5
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• pp.446-455
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• 2010

The research presented covers the design and control method of unmanned ground vehicle (UGV). An electric vehicle is used and is driven by DC motor. The power system on the UGV has been adjusted and actuators have been installed for steering and brake automation. A toggle switch is implemented to easily switch between manual and autonomous states. The UGV state is monitored by a velocity sensor, as well as steering and brake position sensors. An emergency stop device was designed and installed to quickly and safely stop the UGV. Different control methods, including the PID controller, were studied for improved steering responsiveness, and results were confirmed through experimentation. Satisfactory performance was achieved and several possible areas of future research have arisen.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.60 no.2
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• pp.285-292
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• 2011

DC traction power system is operated ungrounded so that minimize the stray current. Because the stray current is still present, a rail potential is increased. The ground faults in the DC railway systems are usually detected by a potential relay(64P). Moreover, if the rail potential goes high in the ordinary operating state because of the traction load, the potential relay would be maloperated. A presented protective relaying algorithm that can identify exactly the faulted region and can distinguish a ground fault from the potential rising of the rail is presented in this paper. This paper presents simulation technique that is very similar to the real operation situation using PSCAD/EMTDC.