• Journal of Korea Water Resources Association
• /
• v.41 no.8
• /
• pp.773-784
• /
• 2008

The present study was carried out to examine flow properties in linear drainage channels such as road surface drainage facilities. The finite difference formulation for the varied flow analysis was solved for flow profiles in the channels. Starting the first step at the control section, the Newton-Raphson method was applied for producing numerical solutions of the equation. We considered two types of linear drainage channels, a channel with one outlet at downstream end and a channel with two outlets at both ends. Moreover, the flow analysis for various channel slopes was performed. However, we considered channels with the two outlets of slopes satisfying the condition that the both ends are the control section. The maximum of those slopes was decided from the relation between the channel slope and the location of control section. The flow of a channel with one outlet was calculated upward and downward from the control section existing in channel or upward from the control section at downstream end. The flow of a channel with two outlets at both ends were calculated for upstream and downstream channel segments divided by the water dividend, respectively and the flow analysis was completed when the water depth at the water dividend calculated from upstream end was equal to that calculated from downstream end. If the slope was larger than the critical slope, the channel with two outlets was likely to behave like the channel with one outlet. The maximum water depth was investigated and compared with that calculated additionally from the uniform flow analysis. The uniform flow analysis was likely to lead a excessive design of a drainage channel with mild slope.

• Journal of Korean Society of Forest Science
• /
• v.65 no.1
• /
• pp.48-53
• /
• 1984

Using the Duff and Noland's method, the annual ring growth patterns of the red pine in the natural stands were examined at two locations; Seocheon, Chungnam-do where the stand had been infested with the pine needle gall midge, Thecodiplosis japonensis, during the years from 1975 to 1978, and Hongsong, Chungnam-do where had been no incidence of the insect damage. The results obtained are as follows: 1) With the normal red pine of 13 year old, the growth pattern in the oblique sequence indicates that the annual growth rates are maximum at the few terminal internodes, and decrease gradually with the downward internodes. Such characteristic of the growth pattern is not clear in the horizontal sequence of annual rings. 2) The indications of the radial growth reduction of the pine tree due to the pine gall midge infestation could be examined with any of three series at the crown level internodes; horizontal, vertical and oblique series. For the basal internodes, however, the horizontal series appeared to be inadequate for the analysis of the damage impact because it seemed to be masked by various factors other than direct effects of the damage. 3) Of the three ways of radial growth analyses, oblique sequence seems to be the most usefull, especially for the detection of the impact on growth caused by incipient or light infestation.

• Journal of the Korean Society of Fisheries and Ocean Technology
• /
• v.52 no.3
• /
• pp.183-190
• /
• 2016

This study carried out an experiment to find out the reaction of hairtail, Trichinus lepturus to the colors of LED light as a basic study on the development of the trolling gear and a method to enable the day-night operation. We used hairtails caught around Seongsan-po, Jeju Island by set nets and hairtail angling. The seven hairtails of the average length 68.9 cm (SD 9.2 cm) and the average weight 135.9 g (SD 47.9 g) were adapted themselves in the experimental water tank, 15 m Self-Governing 1.7 m in height and 1.5 m in depth, and then they were studied. We conducted experiment at the Ocean and Fisheries Research Institute in Jeju Special Self-Governing Province, from November to December 2015, and the sea surface temperature was between 16.5 and $19.5^{\circ}C$. The four colors of LED light, blue, white, green and red, were set up to transmit downward from the marginal area of tank. The 1 meter depth light intensity of LED colors is as follows: $0.09w/m^2/s$ (blue), $0.18w/m^2/s$ (white), $0.04w/m^2/s$ (green) and $0.007w/m^2/s$(red) To know the optimum LED color light, we selected one with better reaction rate after comparison of two colors simultaneously and the selected color was again compared to the other color in a tournament style two times a day (day and night) and ten times totally. The reaction rates were shown as the frequencies of hairtail appearance for 5 minutes in the lighting zone after turning on the LED lights. The reaction rate of the blue was at 97% unlike the red 3% (p < 0.001). The blue was at 75% unlike the green at 25% (p < 0.001). The blue was at 67% unlike the white at 33% (p < 0.001). Therefore, the color of light source showing the highest reaction rate was the blue.

• Journal of the Korean Vacuum Society
• /
• v.16 no.4
• /
• pp.244-249
• /
• 2007

Deadweight piston gauge have been widely used as a fundamental instrument of precise pressure measurement because they are robust, accurate, potable, convenient to use and are able to realize the definition of pressure as farce per unit area. Basically, a deadweight piston gauge consists of a piston mounted vertically in a close-fitting cylinder filled with a gas and weights of known mass values. The pressure to be measured is applied to the base of the piston generating an upward vertical force, and is balanced by the downward gravitational force generated by weights. These instruments can be used to measure pressures above 10 kPa because of tare weights including piston. However, using a variable bell-jar pressure method and a newly developed weight loading device we can extend the application range of deadweight piston gauge to lower pressures. In this paper, we present the practical calibration results for two CDGs(Capacitance diaphragm gauge, MKS) with full-scale ranges of 1.33 kPa and 13.3 kPa, respectively.

• Geophysics and Geophysical Exploration
• /
• v.16 no.1
• /
• pp.36-44
• /
• 2013

We conducted the airborne magnetic and radiometric survey for the characterization of the black shale related and pyrometamorphic uranium deposits distributed in Geumsan area. For the successful characterization of the uranium deposits, the general geological and structural geological features were investigated based on the lithological and linear feature analysis to individual magnetic and radiometric data as the first step. Lithological analysis from the magnetic reduction to the pole and downward continuation map revealed that prominent positive anomalies caused by black and dark gray slate member were clearly recognized as magnetic sources. These results indicate that magnetic survey, even though it is not a direct method for the detection of uranium, can be a useful tool in uranium detection. By the linear feature analysis based on 2nd vertical derivative and curvature map, two linearments corresponded the gray hornfels and black slate member were extracted and in succession, the additional uranium potential zone was inferred. Final discrimination whether uranium-rich or not was confirmed by radiometric and uranium anomaly map. From these analysis, we finally concluded that uranium deposit originated by pyrometamorphic process was confined near the intrusive area only. On the contrary, it was found that black shale related uranium deposit is distributed and extended through out the entire survey area with south-west to north-east direction. In addition, from the linear feature analysis based on radiometric total anomaly map, the typical discontinuous characteristics were recognized in areas where uranium-contained linearments cross the faults. From the above discussion, we concluded that airborne magnetic and radiometric survey are complementary to each other. So it is preferable to carry out simultaneously for the efficient data processing and fruitful interpretation.

• Korean Journal of Cleft Lip And Palate
• /
• v.8 no.2
• /
• pp.71-79
• /
• 2005

Purpose: Maxillary hypoplasia is a common developmental problem of cleft lip and palate. Fair results with distraction osteogenesis have been reported especially when these patients need a large amount of maxillary advancement, instead of orthognathic surgery. The purpose of this study is to evaluate the clinical results with a relatively new distractor, $TS-MD^{(R)}$ (Trans-sinusoidal maxillary distractor, KLS Martin, Tuttlingen, Germany) which was used for the advancement of the maxilla in the cleft patients. Patients and Method: Distraction osteogenesis using $TS-MD^{(R)}$ was performed for four CLP patients (three males and one female) who had maxillary hypoplasia. All patients were over 16 years old. As three patients showed mandibular prognathism as well, bilateral sagittal split ramus osteotomy for mandibular setback was performed at the same time. After consolidation periods of 4 to 12 weeks, the distraction devices were removed and miniplates were placed for simultaneous internal fixation. Results: Three patients showed a large amount of incisal overbite but one patient did not have sufficient maxillary advancement. Le Fort I osteotomy, maxillary advancement and internal fixation should have been performed for the patient when removing the distraction devices. Different from the $clinician{\box}s$ expectation, the amount of maxillary advancement using $TS-MD^{(R)}$ was not sufficient, although the device has rigid mechanical property. Rotation of maxilla during distraction forward and downward was also observed. Conclusion: Even though the maxillary advancement with $TS-MD^{(R)}$ device could be achieved, the clinical control of some characteristics related with the device was necessary. More clinical studies on $TS-MD^{(R)}$ should be performed.

• Maxillofacial Plastic and Reconstructive Surgery
• /
• v.40
• /
• pp.13.1-13.8
• /
• 2018

Background: We evaluated change in the mandibular condyle after orthognathic surgery using cone-beam computed tomography (CBCT) in patients with facial asymmetry. Methods: Thirty patients with skeletal class III malocclusion and mandibular prognathism or facial asymmetry were classified into two groups according to the amount of menton deviation (MD) from the facial midline on anteroposterior (AP) cephalogram: group A (asymmetry, MD ≥ 4 mm; n = 15) and group B (symmetry, MD < 4 mm; n = 15). Position and angle of condylar heads on the axial, sagittal, and coronal views were measured within 1 month preoperatively (T0) and postoperatively (T1) and 6 months (T2) postoperatively. Results: On axial view, both groups showed inward rotation of condylar heads at T1, but at T2, the change was gradually removed and the condylar head returned to its original position. At T1, both groups showed no AP condylar head changes on sagittal view, although downward movement of the condylar heads occurred. Then, at T2, the condylar heads tended to return to their original position. The change in distance between the two condylar heads showed that they had moved outward in both groups, causing an increase in the width between the two heads postoperatively. Analysis of all three-dimensional changes of the condylar head positions demonstrated statistically significant changes in the three different CBCT views in group B and no statistically significant changes in group A. Conclusions: There was no significant difference between the two groups in condylar head position. Because sagittal split ramus osteotomy can be performed without significant change in symmetrical and asymmetrical cases, it can be regarded as an effective method to stabilize the condylar head position in patients with skeletal class III malocclusion and mandibular prognathism or facial asymmetry.

• Journal of the Korean Magnetics Society
• /
• v.18 no.6
• /
• pp.206-210
• /
• 2008

According to the recent reports the bulk bcc Rh is ferromagnetic with a small difference of energy compared to paramagnetic state. In this study, the electronic structure and magnetism for bcc Rh(001) surface are investigated by means of the all-electron full potential linearized augmented plane wave method within the generalized gradient approximation. It is found that the surface ferromagnetic state is preferable over the paramagnetic one. For unrelaxed system, the magnetic moment of the surface layer, $0.48{\mu}B$, is slightly increased comparing with the bulk value, $0.41{\mu}B$ while the value of the subsurface layer, $0.23{\mu}B$, is much smaller than the bulk value. The total energy and atomic force calculations show that the surface layer is relaxed downward and the subsurface layer moves upward to reduce the layer distance between the surface and subsurface layers by 7.0 %. The relaxation effect leads to weakening the surface magnetic properties. Specifically, the value of the magnetic moment of the surface atom is decreased to $0.36{\mu}B$. Since the spin polarization of the subsurface layer is only $0.14{\mu}B$, it is concluded that the bcc Rh(001) surface is rather weakly ferromagnetic.

• Journal of the Korean earth science society
• /
• v.30 no.2
• /
• pp.153-164
• /
• 2009

We examined the regional 1-D deep resistivity structure of the Korean Peninsula using MT data acquired at seven sites located in the Kyongsang Basin and Kyonggi Massif. At the sites located in the Kyongsang Basin, surrounding sea distorts observed MT response and hence this distortion, so called "sea effect", is corrected using an iterative tensor stripping method. The 1-D layered inversion results for the seven MT sites reveal 4 layered structure, which is composed of 1) near surface layer, 2) upper crust, 3) lower crust and upper mantle, and 4) asthenosphere from the surface downward. Conrad interface, which is a boundary between upper and lower crust, is distinctly identified beneath all the MT sites. Conrad interface depth is estimated to about be 17km in the Kyongsang Basin and about 12km in the Kyonggi Massif, while the upper crust of the Kyongsang Basin is about 5 times more resistive than that of the Kyonggi Massif. Finally, asthenosphere is inferred to exist below a depth of approximately 100km with a resistivity of 200-300 ohm-m.

• Journal of the Korean association of regional geographers
• /
• v.6 no.2
• /
• pp.71-82
• /
• 2000

The purpose of this paper is to clarify geomorphic features and development on the boulder stream of granitoid in Korea. Considering the purpose and the method of this paper, three boulder streams are selected : Biseulsan(Mt. Biseul) boulder stream (Daegu city), Maneosan (Mt. Maneo) boulder stream(Gyeongnam province), Geumjeongsan(Mt. Geumjeong) boulder stream (Busan city). The boulder streams mentioned above are bigger in scale and more typical in shape than any other ones in the Korean Peninsula. The main results are summarized as follows. 1. The following are the main features of the boulder streams morphology : the mean gradient is $3{\sim}25^{\circ}$, the longer axes of the component boulders within the deposits averaged about 2m in length, the shapes of the component boulders may be both subangular and subrounded features. 2. The formation of the component boulders is associated with deep weathering of granitoid under warm humid conditions, and the downward movement of boulders occurred by solifluction and frost creep under periglacial conditions. 3. The geomorphic development stage of the boulder streams may be classified into four stages. These boulder streams come under fossil landform stage, the 4th stage ; evidence provided by lichens and weathering features indicate inactive or fossil landform. 4. In generally, boulder streams are well developed on shallow valley floors.