• Proceedings of the Korean Society of Precision Engineering Conference
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• 2013.05a
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• pp.1241-1242
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• 2013

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2009.06a
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• pp.601-602
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• 2009

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2009.06a
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• pp.973-974
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• 2009

• Journal of the Korean Solar Energy Society
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• v.28 no.3
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• pp.7-14
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• 2008

400RT geothermal system which is the biggest capacity among on-operations at present in Korea is measured and evaluated on 23rd${\sim}$26th Jan. 2008 during those days building is not allowed owners and/or tenants to move in. The geothermal system is consist with vertical-typed 112 geothermal heat exchangers which are installed circle-like 1 row with 4m interval, and has 16 units of 25USRT geothermal-source heat pump(GSHP)s. And each 5 units of circulation pump are running for geothermal heat exchangers and hot water supplies. The followings are the results. The temperatures at G.L. -70m of 2 boreholes are varied quite similarly. The average temperature difference between inlet and outlet of geothermal pipes is $4.1^{\circ}C$, and that of hot water supply is $3.2^{\circ}C$, of Zone 3's each 4 GSHPs when being operated. Despite temperature fluctuations by heating loads, the average temperature difference between main pipes of inlet and outlet of geothermal heat exchangers is measured as $4.1^{\circ}C$. This study propose "Geothermal System COP" which includes not only consumed electric power by compressor but also circulation pumps and auxiliary utilities. By comparing the geothermal system COP with GSHP's performance specification, it is clear that the performances of GHSPs of this site are satisfied with the specification.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.38 no.6
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• pp.521-531
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• 2020

QZSS (Quasi-Zenith Satellite System) provides the CLAS (Centimeter Level Augmentation Service) through the satellite's L6 band. CLAS provides correction messages called C-SSR (Compact - State Space Representation) for GPS (Global Positioning System), Galileo and QZSS. In this study, CLAS messages were received by using the AsteRx4 of Septentrio which is a GPS receiver capable of receiving L6 bands, and the messages were decoded to acquire C-SSR. In addition, Multi-GNSS (Global Navigation Satellite System) Code-PPP (Precise Point Positioning) was developed to compensate for GNSS errors by using C-SSR to pseudo-range measurements of GPS, Galileo and QZSS. And non-linear least squares estimation was used to estimate the three-dimensional position of the receiver and the receiver time errors of the GNSS constellations. To evaluate the accuracy of the algorithms developed, static positioning was performed on TSK2 (Tsukuba), one of the IGS (International GNSS Service) sites, and kinematic positioning was performed while driving around the Ina River in Kawanishi. As a result, for the static positioning, the mean RMSE (Root Mean Square Error) for all data sets was 0.35 m in the horizontal direction ad 0.57 m in the vertical direction. And for the kinematic positioning, the accuracy was approximately 0.82 m in horizontal direction and 3.56 m in vertical direction compared o the RTK-FIX values of VRS.

• Journal of the Microelectronics and Packaging Society
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• v.18 no.4
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• pp.11-18
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• 2011

The quantitative interfacial adhesion energy of the Cu-Cu direct bonding layers was evaluated in terms of the bonding temperature and Ar+$H_2$ plasma treatment on Cu surface by using a 4-point bending test. The interfacial adhesion energy and bonding quality depend on increased bonding temperature and post-annealing temperature. With increasing bonding temperature from $250^{\circ}C$ to $350^{\circ}C$, the interfacial adhesion energy increase from $1.38{\pm}1.06$ $J/m^2$ to $10.36{\pm}1.01$ $J/m^2$. The Ar+$H_2$ plasma treatment on Cu surface drastically increase the interfacial adhesion energy form $1.38{\pm}1.06$ $J/m^2$ to $6.59{\pm}0.03$ $J/m^2$. The plasma pre-treatment successfully reduces processing temperature of Cu to Cu direct bonding.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2006.05a
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• pp.15-19
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• 2006

A pulsed laser ablation deposition (PLAD) technique is an excellent method for the fabrication of amorphous carbon (a-C) films, because it can generate highly energetic carbon clusters on a substrate. This paper was focused on the understanding and analysis of the motion of C particles in laser ablation assisted by Ar plasmas. The simulation has carried out under the pressure P=50 mTorr of Ar plasmas. Two-dimensional hybrid model consisting of fluid and Monte-Carlo models was developed and three kinds of the ablated particles which are carbon atom (C), ion ($C^+$) and electron were considered in the calculation of particle method. The motions of energetic $C^+$ and C deposited upon the substrate were investigated and compared. The interactions between the ablated particles and Ar gas plasmas were discussed.

• Korean Journal of Ichthyology
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• v.7 no.2
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• pp.203-207
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• 1995

A fish, collected from the Tongbok stream, secondary tributary of the Somjin River system, appeared to be a hybrid between Cobitis longicorpus and Misgurunus anguilicaudatus. The morphological features of this specimen have suborbital spine and distinctive black small spots at the back of its opecleula characterized by C. longicorpus. However, it has totally different body color patterns on the sides of body from the C. longicorpus and The structure of lami-na circularis was less distinctive than that of C. longicorpus. Body measurements of the specimen were similar to the C. longicorpus with the exceptions as caudal peduncle depth(CPD), caudal peduncle length(CPL), predorsal length and CPD/CPL. CPD/CPL were sightly higher and longer than that of the C. longicorpus, and predorsal length was more similar to the M. anguilicaudatus than the C. longicorpus. CPD/CPL value was intermediate between the two parental species. This results indicate that the specimen used in this study is a hybrid between Cobitis longicorpus and Misgurunus anguilicaudatus.

• Journal of the Mineralogical Society of Korea
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• v.11 no.2
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• pp.117-125
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• 1998

Crystallization behavior of platinum minerals within Pt-Sb-Bi bearing ore magmas and mineralogical properties of the existing minerals were investigated at 1,00$0^{\circ}C$ by synthetic experiment. High purity reagents were used as starting materials and silica tubings as containers. Reaction products were analysed by reflecting microscopy, X-ray diffraction, electron probe microanalysis, and micro-hardness test. Stable minerals at 1,00$0^{\circ}C$ are platinum, electron probe microanalysis, and micro-hardness test. Stable minerals at $1,000^{\circ}C$ are platinum, stump-flite (PtSb) and geversite (PtSb2). They are in equilibrium with liquid (ore magma). Platinum contains considerable amount of Sb of 7.5 at.%, whereas Bi only up to 0.9 at.%. Pure stumpflite is hexagonal with space group P63/mmc, and unit cell parameters are a=4.1318(6), c=5.483(1)$\AA$. VHN50=417(2)$\AA$. Geversite has cubic structure with space group Pa3. Cell parameters are a=6.4373(2)$\AA$ and Vicker hardness values VHN50=663.5 (566~766). Both stumpflite and geversite show solid solution and their end-members are Pt48.8Sb40.7-Bi10.5, and Pt33.7-Sb59.8Bi6.5, respectively. Although stumpflite (m.p. $1,043^{\circ}C$) and unnamed PtBi (m.p. 7$65^{\circ}C$) do not form a complete solid solution at $1,000^{\circ}C$, they are known, at $600^{\circ}C$, to form a continuous solid solution. Geversit (m.p. $1,226^{\circ}C$) also forms complete solid solution with insizwaite (m.p. $660^{\circ}C$). Unit cell dimensions of the minerals above increases with the amount of Bi substituting for Sb.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.9 no.2
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• pp.171-179
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• 1997

During the day time in summer, peak of air conditing load, and electric power management system lies under overloaded condition. The reason is the enlarged peak load value of electric power caused by increased air-cooling load in summer. To prevent load concentration during day time and overloaded condition of power management system, some energy storage methods are suggested. One of these methods is ice storage system. Water has some good properties as P.C.M.(Phase Chang Material) : Its melting point is the range of required operation temperature. It has large specific latent heat and is chemically stable compared to other organic or inorganic substances. It is cheap and easy to treat. This study represents experimental results of heat transfer characteristics of P.C.M. under the outward melting process in a vertical cylinder. We experimented with twelve combinations of conditions, i.e., three different inlet temperatures($7^{\circ}C,\;4^{\circ}C\;and\;1^{\circ}C$), two working fluid directions(upward and downward), and two aspect ratios, H/R(4 and 2). At the inlet temperature of $7^{\circ}C$ and $4^{\circ}C$, there was temperature stagnation region where the temperature of P.C.M. remains constant at $4^{\circ}C$ regardless of aspect ratio and direction of working fluid. This temperature stagnation occurs as the water, at its maximum density, flows down to the lower region. The phase change interface formed bell-shaped curve as the melting process continued. With a new set of conditions(4H/R, inlet temperature $4^{\circ}C$ and $1^{\circ}C$, downward/upwerd inlet direction), the movement of phase change interface was faster when the working flued inlet direction was downward. With the same set of conditions, melting rate and total melting energy were larger when the working fluid inlet direction was downward. The results were reversed when the other sets of conditions were applied.