• Journal of Korean Society of Forest Science
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• v.95 no.1
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• pp.55-59
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• 2006

The objectives of this study, an analysis of the morphological characteristics among six provenances of a rare Rhododendron micranthum could be used for the conservation of gene resources and could provide information on superior trees selection. The following results were obtained. Approximately Mt.worak region showed larger values at petal character. On the other hand, Bonghwa region showed smaller values at petal character. Yeonha-ri region showed larger values at leaf character. On the other hand, Bonghwa region showed smaller values at leaf character. The results of principal component analysis (PCA) for morphological characteristics showed that the first for principal components(PC's) explained 41.6% of the total variation. From th third PC explained 81.5% of the total variation. The first PC was correlated with those characteristics that were mainly related to the Petal length (PL), Leaf length (LL) width (LW), Stigma length (SL). The second PC was correlated with the Petiole length (PTW), Anther length (AL). The third PC was correlated with the Flower pedicel length (FPL), Filament length (FL). Therefore, these characteristics was important to analysis of the variation for morphological characteristics among provenances of Rhododendron micranthum. Cluster analysis using single linkage method based on morphological characteristics showed that six provenances of Rhododendron micranthum could be clustered into three groups. Group I is Jicdong-ri, Group II is Mt.worak and Yeonha-ri, and Group III is Taeback, Bonghwa, and Samcheok. These results corresponded well with that of principal component analysis.

• MALSORI
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• no.50
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• pp.1-22
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• 2004

The aim of this paper is to show what are the sociolinguistic variables of word-initial length loss in Seoul dialect. 350 people were inquired to pronounce 40 words. Among the informants, 152 were male, and 198 were female. In terms of their age, 49 were twenties, 70 were thirties, 69 were forties, 71 were fifties, and 91 were above sixties. According to our statistics, 18 words show sociolinguistic variation by age, and sex was not a variable. So we can conclude that Seoul dialect is undergoing length loss by age at least. But we need to enlarge the number of words and informants and we also need to adopt other variables like social level, education etc for better understanding of Seoul dialect.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.30 no.2 s.245
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• pp.161-169
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• 2006

The spray characteristics of liquid jet in cross flow with variation of injection angle are numerically studied. Numerical analysis was carried out using KIVA code, which was modified to be suitable for simulating liquid jet ejected into cross flow. Wave model and Kelvin-Helmholtz(KH)/Rayleigh-Taylor(RT) hybrid model were used for the purpose of analyzing liquid column, ligament, and the breakup of droplet. Numerical results were compared with experimental data in order to verify the reliability of the physical model. Liquid jet penetration length, volume flux, droplet velocity profile and SMD were obtained. Penetration length increases as flow velocity decreases and injection velocity increases. From the bottom wall, the SMD increases as vertical distance increases. Also the SMD decreases as injection angle increases.

• The Transactions of the Korean Institute of Electrical Engineers C
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• v.53 no.12
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• pp.616-619
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• 2004

Electrical circuits with semiconductor are very weak against lightning surge. The surge protective devices for electronic circuit and AC power lines are becoming more widely used. To achieve effective method of surge protection, there are needs for correlation between lightning surge and indoor wire length or installation height of indoor wire. The aim of this present work is to investigate the propagation characteristics of lightning surge according to variation of wire length. As a consequence, the maximum voltage at the end of the open wire in proportion to length of indoor wire. Therefore this result may be raw data for establishment of surge protection system.

• Proceedings of the IEEK Conference
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• 2008.06a
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• pp.551-552
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• 2008

This paper presets a results of frequency response in variation of wire bonding length. A gold ball bonding is used as a wire bonding process, and a DPDT(double pole double thru) switch is adapted as a device for test. Wire length is ranged from 442um to 833um and a measured frequency range is from 1 GHz to 6 GHz. Little difference are measured in insertion loss and return loss depending on wire length. Measured S21 and S11 are -0.58 dB and -17.7 dB, respectively. S21 insertion loss is rising up and S11 insertion loss is falling down as the frequency is increased.

• Journal of Industrial Technology
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• v.19
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• pp.59-65
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• 1999

This study is to analyze turbulent flow over a backward-facing step in a rectangular duct. The side wall effects on the internal flow were determined by varying the aspect ratio(defined as the step span-to-height ratio) from 1 to 20. In the flow behind a backward-facing step, separation, recirculation and redeveloping is occurred frequently. These phenomena appear in a particular variation by varying the aspect ratio. The results show that the aspect ratio has an influence on the velocity and reattachment length. When the AR is increased, the reattachment length is increased. For 6 over aspect ration, the rate of increase is decreased. The length of recirculation in the upper corner is increased, as the increase of aspect ration. It's width is not changed in the variation of aspect ration. The transverse, streamwise and spanwise velocities were decreased along the flow down stream of the step.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.17 no.10
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• pp.1034-1040
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• 2004

The latch-up current and switching characteristics of MOS-Controlled Thyristor(MCT) are studied with variation of the channel length and impurity concentration. The proposed MCT power device has the lateral structure and P-epitaxial layer in substrate. Two dimensional MEDICI simulator is used to study the latch-up current and forward voltage-drop from the characteristics of I-V and the switching characteristics with variation of impurity concentration. The channel length and impurity concentration of the proposed MCT power device show the strong affect on the anode current and turn-off time. The increase of impurity concentration in P and N channels is found to give the increase of latch-up current and forward voltage-drop.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.26 no.12
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• pp.553-558
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• 2014

Geothermal energy can be used with a geothermal heat pump or an earth-to-air heat exchange system (EAHES), which is referred to as a "cooling tube" in Korea. In this study, we suggest EAHES burial guidelines in terms of the parameters of buried pipe length and air velocity regarding the exit air temperature of EAHES. The exit air temperature for EAHES in three regions (Changwon, Busan and Seoul) was calculated with variation in buried pipe length and air velocity at ${\Phi}100mm$ and ${\Phi}200mm$. In conclusion, variation in the buried pipe length is more effective than that of air velocity to achieve the required exit air temperature.

• Journal of the Society of Cosmetic Scientists of Korea
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• v.16 no.1
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• pp.18-29
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• 1990

In this report, the variation of skin surface between before treatment and after treatment was investigated by skin image analyzer. The 30 volunteers were applied cream and lotion on the forearm Inside for 4 weeks, and the measurement parameter of skirl surface was adopted peak, length, height, and width. The results were as follows ; 1. variation trends of parameters was showed that number of peaks were increased, but length, height and width were decreased. 2. The order of improvement for skin surface are as follow ; height > length > peak > width. 3. And also disclosed that the number of peak has a correlation with width, and length has a correlation with height.

• Proceedings of the Optical Society of Korea Conference
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• 1989.02a
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• pp.113-118
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• 1989

By using the single mode optical fiber, we fabricated Fiber-optic Fabry-Perot interferometer (FFPI). The change over a wide range in the optical path length of a FFPI is observed. The temporal movement of the interference fringes by external condition to P.Z. T) is converted to circular motion on an oscilloscope display and then recorded with a micro-computer. The two output voltages of the D/A converters are applied to X and Y terminals of oscilloscope to display circular motion on oscilloscope. Thus the direction of phase shift can be determined with observing the direction of circular motion. The variation of the optical length can be measured by calculating the angle of spot of circle with an accuracy of λ/90 wave length due to variation of temperature in this system 2.7x10-4$^{\circ}C$.