• Journal of the Korean Crystal Growth and Crystal Technology
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• v.1 no.1
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• pp.60-65
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• 1991

The hydrothermal growth of $GaPO_{4}$ Single Crystals was carried out by the horizontal temperature gradient method. The most promising solvents for the crystal growth of $GaPO_{4}$ are $H_{3}PO_{4}$ and HCl solutions. Single crystals have been hydothermally grown at temperatures over the range $210-290^{\circ}C$ in these solutions with seed crystals. The glowth rates in HCl solution were higher than that for comparable conditions in $H_{3}PO_{4}$ solution. Morphologies of crystals grown at temperatures below $200^{\circ}C$ tended to be bounded by small major rhombohedral(10$\bar{1}$1) faces. In the temperature range from 200 to $430^{\circ}C$, the single crystals have morphologies bounded by prism (10$\bar{1}$0), small major rhombohedral(10$\bar{1}$1) and minor rhombohedral(01$\bar{1}$1) faces at the early stage, and grew with well developed basal(0001) faces by increasing the growth temperature.

• Proceedings of the Korean Society of Coastal and Ocean Engineers Conference
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• 1996.10a
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• pp.109-114
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• 1996

In a linear dispersive system, the combined effect of water wave frnnsformations such as refraction, diffraction, shoaling, and reflection can be predicted by the mild-slope equation which was developed by Berkhoff (1972) using the Galerkin-eigenfunction method. In the derivation of the equation, he assumed a mild slope of the bottom $\nabla$h/kh << 1 (where $\nabla$ is the horizontal gradient operator, k is the wavenumber, and h is the water depth) and thus neglected second-order bottom effect terms proportional to O($\nabla$h)$^2$ and O($\nabla$$^2$h). (omitted)

• Proceedings of the Korea Association of Crystal Growth Conference
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• 1998.06a
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• pp.157-159
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• 1998

Sapphire crystals were grown by Horizontal Bridgman method. The effects of sliding rate (growth rate) of Molybdenum container, growth atmosphere, temperature gradient and orientation of see on crystal qualities were investigated. The size of the crystals grown was up to 150-200 mm in length, 90 mm in width and 25-35 mm in thickness. Crystals grown under the optimum conditions were colorless, transparent and could not be observed and macroscopic defects, such as bubbles, cracks, twins and mosaic structure. With the grown crystals, prototypes of sapphire substrate for blue wafers were characterized. As a result, we can get hight quality of sapphire wafers with c-axis, 1.5 inches in diameters and 0.33 mm in thickess.

• Journal of Advanced Marine Engineering and Technology
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• v.30 no.2
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• pp.218-224
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• 2006

Experimental results for pressure gradient of HCs refrigerants R-290. R-600a. R-1270 and HCFC refrigerant R-22 during condensing inside horizontal double pipe heat exchangers are presented. The test sections which have the tube inner diameter of 10.98mm. and the tube inner diameter of 8mm are used for this investigation. Hydrocarbon refrigerants have higher pressure drop than R-22 in both test sections with the diameters of 12.70mm and 9.52mm. Pressure drop increased with the increase of the mass flux. These results form the investigation can be used in the design of heat transfer exchanger using hydrocarbons as the refrigerant for the air-conditioning systems

• Korean Journal of Optics and Photonics
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• v.7 no.1
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• pp.24-27
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• 1996

We describe the optical trapping of yeast particles of $3~4\mu\textrm{m}$ in water solution using a diode laser operating at 790 nm. The yeast particles are trapped by a laser focus and are moved in 2- or 3-dimensions. This confirms the concept of negative light pressure by the gradient force due to the difference of the index of refractions of solutions and particles. By moving yeast particle vertically to the laser beam axis, we measured the horizontal component of the trapping force and compared it with the laser power.

• Proceedings of the KIEE Conference
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• 1995.07b
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• pp.1002-1005
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• 1995

This paper presents an enhanced preprocessing and recognition algorithm for automatic vehicle license plate recognition system. The algorithm first applies horizontal gradient filter followed by thresholding and mathematical morphology operation for preprocessing. The final stage of the preprocessing is the application of connected component analysis in order to estimate the license plate region. For the recognition of the serial numbers of the plates, we developed a very effective algorithm. We call this zerocrossing count algorithm. This paper presents a detail of this algorithm and compare the performance with a template matching algorithm which utilizes correlation coefficient.

• Proceedings of the KIEE Conference
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• 2007.07a
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• pp.1578-1579
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• 2007

In this paper, we propose a new method for designing the steering controller of Autonomous Underwater Vehicle(AUV) using a Self-Recurrent Wavelet Neural Network(SRWNN). The proposed control method is based on a direct adaptive control technique, and a SRWNN is used for the controller of horizontal motion of AUV. A SRWNN is tuned to minimize errors between the SRWNN outputs and the outputs of AUV via the gradient descent(GD) method. Finally, through the computer simulations, we compare the performance of the propose controller with that of the MLP based controller to verify the superiority and effectiveness of the propose controller.

• Proceedings of the KSR Conference
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• 2008.11b
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• pp.1-9
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• 2008

A wide metropolitan railway and a metropolitan railway in metropolitan area are transportation systems to cope with possible large demand and are under construction continually. A wide metropolitan railway and a metropolitan railway in metropolitan area are running with low speed because it is difficult to improve train speed according to short distances between stations and topography. There is a few study on improving commercial speed on the existing wide metropolitan railway and metropolitan railway in metropolitan area, but there is no study on a new wide metropolitan railway. This study present speed-up scheme of the Sosa-Wonsi line by enlarging the curve radius, reducing the horizontal steep gradient, reducing the stopping time, speeding up at underground section, and installing the PSD, etc. This scheme is evaluated using the simulation technique.

• Korean Journal of Agricultural and Forest Meteorology
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• v.20 no.1
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• pp.135-143
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• 2018

The effect of elevated temperature on temperate paddy rice will be significant for dependable food supply in East Asia. Using temperature gradient field chamber (TGFC), which was designed to make the horizontal air temperature gradient by $0^{\circ}C$ to $3^{\circ}C$ higher than outside, we examined the measurement to understand the effects of extremely high temperature on paddy rice. In particular, the data of the year 2016, the worst heat wave in over 22 years, was analyzed in this study. The rice height in the relatively warmed condition was rapidly increased during early growth stage. However, the average grain weight and number of spikelet per panicle in the warmed chamber condition were gradually declined with increasing air temperature averaged for 40 days after first heading in each chamber. In particular, the grain yield was more dramatically decreased by the raising temperature because the percent ripened grain was quickly dropped as getting over the threshold temperature for pollination. Therefore, the surplus photosynthetic product by such lower grain filling rate may disturbed the decreases of the NDVI (Normalized Difference Vegetation Index) and SPAD chlorophyll values after first (normal) heading. In addition, the late-emerging head grain were appeared. However, this yield was too small to recover the normal yields decreased by extremely high temperature condition. Our result represented that the warmed condition in 2016 would be the critical limit for the stable yield of temperate paddy rice.

• Journal of Korean Society of Forest Science
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• v.77 no.2
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• pp.235-241
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• 1988

This study was carried out to identify the variation of culm characteristics of Phyllostachys bambusoides associated with attitudinal gradient in Mt. Jiri. The results obtained were summarized as follows : It was estimated that the average temperature at the altitude of 400 meters of Mt. Jiri was $12^{\circ}C$ which was closely associated with the horizontal distributions. It was observed that frequency distribution of the culm height, D.E.H. and clear length from the altitude of 200 meters to 400 meters shown at higher than that from 500 meters to 600 meters, and that frequency of clear length/culm height showed about equal for both altitude ranges. In the case of culm height, D.E.H. and clear length/culm height, coefficients of variation ranged from 15 percent to 25 percent, and those of clear length were over 25 percent for both altitude ranges. It was observed that culm height, D.E.H., clear length and clear length/culm height among each altitude ranges were significant at the 1 percent level. The Duncan's Test of culm characteristics among altitude ranges distinguished bamboos of below 400 meters from bamboos of over 500 meters. The correlation coefficients among culm characteristics of Phyllostachys bambusoides associated with attitudinal gradient were shown to be highly significant. In conclusion, the variation of calm characteristics of Phyllostachys bambusoides was large for below 400 meters and these results suggest that planting of the species should be done below 400 meters.