• Proceedings of the KSME Conference
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• 2000.04a
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• pp.25-30
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• 2000

Residual stresses induced in U-bending and tube-to-tubesheet joining processes of PWR's steam generator row-1 tube were measured by X-ray method and Hole-Drilling Method(HDM). The stresses resulting from the Internal pressure and the temperature gradient in the steam generator were also estimated theoretically. In U-bent lesions, the residual stresses at extrados were induced with compressive stress(-), and its maximum value reached -319 MPa in axial direction at ${\psi}=0^{\circ}$ in position. Maximum tensile residual stress of 170MPa was found to be at the flank side at Position of${\psi}=90^{\circ}$, i.e., at apex region. In tube-to-tubesheet fouling methods, the residual stresses induced by the explosive joint method were found to be lower than that by the mechanical roll method. The gradient of residual stress along the expanded tube was highest at the. transition region, and the residual stress in circumferential direction was found to be higher than the residual stress in axial direction. Hoop stress due to an internal pressure between primary and secondary side was analyzed to be 76 MPa and thermal stress was 45 MPa.

• Proceedings of the KSME Conference
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• 2008.11a
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• pp.1742-1746
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• 2008

An EHD (Electro-Hydro-Dynamic) jet for electrostatic inkjet head shows advantages to print micro-size patterns using various inks because it can generate sub-micron droplets and can use highly viscous inks. Thus, many researchers in industrial fields are concerned about the EHD jet in these days. Since the basic principle of the EHD jet is to form a droplet from an apex of meniscus at the end of the nozzle, the ejection mechanism can be changed by the shape of the meniscus. The stable ejection of the droplet is greatly affected by the shape of the meniscus which is also influenced by surface characteristics of the nozzle, electric potential and ink properties. Experiments have been performed using the nozzles with hydrophilic and hydrophobic coatings in this study. The hydrophobic nozzle forms the stable droplets in wider range of the electric potential than the hydrophilic nozzle does.

• Journal of Korean Society of Forest Science
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• v.97 no.4
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• pp.452-457
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• 2008

In order to develop an efficient micropropagation technique effect of plant growth regulators (PGRs) affecting on shoot proliferation from shoot apex in Pyrus ussuriensis was tested. Generally, there was no conspicuous effect on shoot induction by the treatment of PGRs and one or two shoots/explant were induced when cultured on MS medium supplemented with BA and/or BA plus NAA. Both apical shoot necrosis and hyperhydric shoots were observed frequently in multiplied shoots, and callus was formed at the basal part of shoots. About 20% spontaneous rooting was achieved in growing shoots, however the proliferated shoots exhibited poor rooting rate in gelrite supported media. When we tried to ex vitro rooting of the shoot cutting, the shoot cuttings rooted up to 50% with 100 mg/L IBA application. The rooted plantlets grew normally after acclimatization in the greenhouse.

• The Journal of the Acoustical Society of Korea
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• v.22 no.6
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• pp.505-511
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• 2003

As the technique of automobile industry is being advanced, the advancement of vehicle ride is being required. In order to achieve this purpose, the study on the vibration which are produced by moving vehicle is carried out actively. In order to analysis, the tire vibration characteristics for passing over a cleat, the tire is modeled with 7-DOFs (degree of freedom). The model is verified against simulations and experiments. The effects of proposed tire design parameters such as the tire tread rubber, tread ring, apex are considered. According to the results of analysis, the tire design parameters that can reduce the tire and wheel vibration quantity are conducted.

• The Research Journal of the Costume Culture
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• v.11 no.4
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• pp.562-577
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• 2003

The object of my research is to inquiry into the immediate constituent and techniques of underwear after looking into basic theory of underwear, techniques by materials classified according to the matter of elasticity, and studying flat pattern and draping which are basis of corset and brassiere structure focusing on corsetry among underwears and production techniques. Various papers are referenced for theoretical study and the elements and techniques of underwear are analyzed based on photographical materials. This paper concludes as follows. To make the flat pattern of corset and brassiere fit to the body tightly, design dart two times without any space and draw smaller than the body. To support the breast sufficiently, move the side seam 1¼″ to the front panel and the seam should pass the apex in all occasions. For draping, dart should be added into short of elasticity materials in the past but dart is no use these days since the material today is extremely elastic. It is possible now to show the body line with only the seam or a pattern. In a case of elastic material, set the elastic direction to the grain line and have a draping as pulling from the center to the out side. As production technic, for an hem, put a zigzag stitch in elastic materials with a 10-20% short elastic band, pulling the band. Then make 3/16″-1/4″ short inseam.

• Journal of Korean Academy of Nursing
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• v.29 no.4
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• pp.780-789
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• 1999

This study was conducted to identify the attributes constituiting Korean social support and to validate the results of the previous study ‘Search for the meaning of social support in Korean Society.’ The informants were 41 Korean middle-aged women in three cities Seoul, Daejun and Daeku. The data were collected through indepth interviews using the interview guide from Jun. 1994 to Jun. 1995. The interview guide was developed in the simulated situations of ‘Stroke attack’ which expected to be in need of social support. The women were asked to answer what they felt and the appropriate terms representing the situations. Data analysis were conducted by content analysis. Consequently, the Korean social support pyramid was modified as follows ; Support is the apex of the pyramid. The four sides of the pyramid are made up of ‘Jung’(Bound by ties of affection, regard or shared common experience, Connectedness), Do-oom(both emotional and material help), Mi-dum(Faith or belief in) and Sa-Rang(Love). The base of the pyramid is ‘yun’(the basic network of relationships in Korean culture) that connote the meaning of Eunhae(Benevolence), Euimu(duty, responsibility) and Dori(obligation).

• Journal of Oral Medicine and Pain
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• v.17 no.2
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• pp.119-128
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• 1992

In order to evaluate the relationship of age with the developmental stage on mandibular second molars in female, the author examined the radiographs in standard films taken by intraoral paralleling technic and analysed the development of 620 roots of 310 females ranged from 10 to 18 years. The development was divided into 7 stages : Crown complete (Cr.C.), Root lengthed 1/4(R.1/4), Root length 1/2 (R.1/2), Rooth length 3/4 (R.3/4), Rooth length complete (R.C), Apex 1.2 closed (A. 1/2), Apical closure complete (A.C) The obtained results were as follows : 1. The formation of roots in fulllength of mandibular second molars was completed at 14.21-year-age in mesial root and at 14.96-year-age in distal root. 2. The formation of apical foramen of mandibular second molars was completed at 17.11-year-age in mesial root and at 17.53-year-age in distal root. 3. The mesial root of mandibular second molar was generally developed earlier than distal root (p<0.01) 4. Coefficients of correlation and regression equations between for age(Y) and the developmental stage of mandibular second molar(X) were "Y=1.53X+6.54, r=0.91 (p<0.01)" in mesial root and "Y=1.52X+7.11, r=0.92(p<0.01)" in distal root respectively.l root respectively.

• Imaging Science in Dentistry
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• v.38 no.2
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• pp.103-107
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• 2008

Purpose: The purpose of this study was to evaluate the relationship between the position of mesiodens and its complications. Materials and Methods: The subjects for this study consisted of 172 patients with mesiodens. Panoramic radiographs and cross-sectional tomography were taken of all of the subjects. Their clinical records and radiographs were analyzed in order to study the direction and vertical and sagittal position of mesiodens, as well as complications caused by mesiodens. Results: The number of mesiodens was one in 112 cases (65.1%) and two in 60 cases (34.9%). Complications were found in 121 mesiodentes (52.2%), with being median diastema the most frequent. The incidence of complications was high in erupted mesiodens (75.0%), in horizontal mesiodens (89.8%) and in mesiodens located within the arch (75.7%), but was low in mesiodens impacted above apex (29.8%), in normal position (34.4%) and in palatally positioned mesiodens (46.5%). Conclusion: It was suggested that the frequency of complications was different according to the vertical position, the direction of the crown and the sagittal position.

• Proceedings of the KSME Conference
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• 2000.04b
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• pp.535-540
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• 2000

The objective of the present study is to visualize the pulsatile flow fields by using three-dimensional computer simulation and the PIV system. A closed flow loop system was built for the steady and unsteady experiments. The Harvard pulsatile pump was used to generate the pulsatile pressure and velocity waveforms. Conifer powder as the tracing particles was added to water to visualize the flow field. Two consecutive particle images were captured by a CCD camera for the image processing. The cross-correlation method in combination with the moving searching area algorithm was applied for the image processing of the flow visualization. The pulsatile flow fields were visualized effectively by the PIV system in conjunction with the applied algorithm. The range validation and the area interpolation methods were used to obtain the final velocity vectors with high accuracy. The finite volume predictions were used to analyze three-dimensional flow patterns in the bifurcation model. The results of the PIV experiment and the computer simulation are in good agreement and the results show the recirculation zones and formation of the paired secondary flow distal to the apex of the bifurcated model. The results also show that the branch flow is pushed strongly to the inner wall due to the inertial force effect and helical motions are generated as the flow proceeds toward the outer wall.

• Proceedings of the KSME Conference
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• 2003.11a
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• pp.765-768
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• 2003

The objective of the present study was to visualize the pulsatile flow field in a branching model by using the high-resolution PIV system. A bifurcated flow system was built for the experiments in the pulsatile flow. Harvard pulsatile pump was used to generate the pulsatile velocity waveforms. Conifer powder as the tracing particles was added to water to visualize the flow fields. Two consecutive particle images at several cross sections of the flow filed were captured by the CCD cameras ($1K{\ast}1K$ and $640{\ast}480$). The results after the image processing clearly showed the recirculation zones and the formation of the paired secondary flows from the distal to the apex in the bifurcated model. The results also indicated that the flow velocities in the inner wall moved faster than those in the outer wall due to the inertial force effects and the helical motions generated in the branch flows as the flow proceeded toward the outer wall. While the PIV images from the $1K{\ast}1K$ camera were closer to the simulation results thantheimagesfromthe640${\ast}$480camera,bothresultsofthePIVexperimentsusingthetwocamerasgenerallyagreed quitewellwiththeresultsfromthenumericalsimulation.