• Proceedings of the Korean Society of Tribologists and Lubrication Engineers Conference
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• 1999.06a
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• pp.162-169
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• 1999

Herringbone groove journal bearing (HGJB) is developed to improve the static and dynamic performances of hydrodynamic journal bearing. Conventional studies on HGJB were based on the Narrow Groove theory assuming that the number of grooves approaches infinity. In this study, an oil lubricated HGJB is analyzed using Finite Element Method. Load carrying capacity, attitude angle, stiffness and damping coefficients are obtained numerically for various bearing configurations especially for the inclined width ratio and asymmetric ratio and compared with the results obtained using Finite Volume Method. The bearing load and stability characteristics are dependent on geometric parameters such as inclined width ratio, asymmetric ratio, groove depth ratio, groove width ratio, groove angle.

• Tribology and Lubricants
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• v.16 no.6
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• pp.425-431
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• 2000

Herringbone groove journal bearing (HGJB) is developed to improve the static and dynamic performances of hydrodynamic journal bearing. Conventional studies on HGJB were based on the Narrow Groove theory assuming that the number of grooves approaches infinity. In this study, an oil lubricated HGJB is analyzed using Finite Element Method. Load carrying capacity, attitude angle, stiffness and damping coefficients are obtained numerically for various bearing configurations especially for the inclined width ratio and asymmetric ratio and compared with the results obtained using Finite Volume Method. The bearing load and stability characteristics are dependent on geometric parameters such as inclined width ratio, asymmetric ratio, groove depth ratio, groove width ratio, and groove angle.

• The Bulletin of The Korean Astronomical Society
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• v.42 no.2
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• pp.82.3-83
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• 2017

We investigate the relationships between the peak fluxes of 18 solar energetic particle (SEP) events and associated coronal mass ejection (CME) 3D parameters (speed, angular width, and separation angle) obtained from SOHO, STEREO-A and/or B for the period from 2010 August to 2013 June. We apply the STEREO CME Analysis Tool (StereoCAT) to the SEP-associated CMEs to obtain 3D speeds and 3D angular widths. The separation angles are determined as the longitudinal angle between flaring regions and magnetic footpoints of the spacecraft, which are calculated by the assumption of Parker spiral field. The main results are as follows. 1) We find that the dependence of the SEP peak fluxes on CME 3D speed from multi-spacecraft is similar to that on 2D CME speed. 2) There is a positive correlation between SEP peak flux and 3D angular width from multi-spacecraft, which is much more evident than the relationship between SEP peak flux and 2D angular width. 3) There is a noticeable anti-correlation (r=-0.62) between SEP peak flux and separation angle. 4) The multiple regression method between SEP peak fluxes and CME parameters shows that the longitudinal separation angle is the most important parameter, and the CME 3D speed is secondary on SEP peak flux.

• Journal of Oral Medicine and Pain
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• v.47 no.1
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• pp.27-37
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• 2022

Purpose: This study aimed to broaden our understanding of the predisposing factor and treatment of dislocation by analyzing and evaluating the morphology of the articular eminence (AE) in subjects with temporomandibular joint (TMJ) dislocation using cone beam computed tomography (CBCT). Methods: The subjects were divided into two groups: dislocation (31 subjects) and control (32 subjects). CBCT was used to examine 126 TMJs in 63 subjects (26 males, 37 females). The height, width, and posterior slope of the AE were measured in the parasagittal plane. The posterior slope was measured using the "top-roof line angle (TR angle)" method and the "best-fit line angle (BF angle)" method. The AE on the left side (AEL) and the AE on the right side (AER) of the subjects in the dislocation group were separately analyzed and compared with the control group after taking measurements. The average value of both sides was used when comparing with subjects with bilateral dislocation. Results: Dislocations were more frequent in females (67.7%) than in males (32.3%). The dislocation group showed a gentler TR angle than the control group in the AER and in the average of AE on the both sides (AEB). The same group also showed a wider AE in the AEL and the AER (p<0.05). In subjects with unilateral dislocation, the width of the AE with dislocation was narrower and the TR angle and BF angle was steeper than the other side without dislocation (p<0.05). Conclusions: In subjects with unilateral TMJ dislocation, the posterior slope of the AE is steeper, and the width is narrower at the site of dislocation compared to the site without dislocation. However, in subjects with bilateral TMJ dislocation, AEB were wider, and the mean value of the posterior slope of AEB was gentler than that of the control group.

• Imaging Science in Dentistry
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• v.37 no.1
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• pp.19-26
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• 2007

Purpose : To examine whether the maxillofacial skeletal morphology correlates with the condylar position and the anatomic characteristics of articular eminence using measurements of lateral cephalometric radiographs and individualized sagittal temporomandibular joint (TMJ) tomographs. Materials and Methods : I compared measurements of 202 TMJs of 101 orthodontic patients of Kangnung National University Dental Hospital. 1 used Pearson's correlation for comparison of the measuring values in lateral cephalometric radiographs and individualized sagittal TMJ tomographs. Results : Large occlusal plane angle tendency showed decreased width of posterior eminence slope, decreased depth of articular fossa and decreased posterior slope angle of eminence. Large mandibular plane angle tendency showed decreased superior joint space, decreased depth of articular fossa and decreased posterior slope angle of eminence. Large genial angle tendency showed decreased depth of articular fossa, decreased posterior slope angle of eminence and anterior position of condylar head. Large anterior facial height and large posterior facial height tendency showed increased width of posterior slope of eminence, increased depth of articular fossa, increased posterior slope angle of eminence and posterior position of condylar head. Conclusion : Maxillofacial skeletal morphology has correlation with the anatomic characteristics of TMJ. Individualized sagittal TMJ tomographs can provide useful information for anatomical analysis of TMJ.

• Proceedings of the Korean Society of Crop Science Conference
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• 2022.10a
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• pp.280-280
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• 2022

Tiller angle, defined as the angle between the main stem and its side tillers, is one of the main target traits selected inbreeding to achieve the ideal plant type and increase rice yield. Therefore, the discovery and identification of tiller angle-related genes can provide architecture and yield. In the present work, using QTL analysis hence a total of 8 quantitative trait loci (QTLs) were detected based on the phenotype data of tiller angle and tiller crown width in two years. Among them, four QTLs (qTA9, qCW9, qTA9-1, qCW9-1) were overlapped at marker interval RM6235-RM24288 on chromosome 9 with a large effect value regarded as stable major QTL. Twenty tiller angle-related genes were selected from the target region and the relative gene expression levels were checked in five compact type lines, five spreading type lines, and their parental lines. Finally, OsSA URq9 which belongs auxin-responsive SMALL AUXIN UP RNA (SAUR) protein family was selected as a target gene. Overall, this work will help broaden our understanding of the genetic control of tiller angle and tiller crown width, and this study provides both a good theoretical basis and a new genetic resource for the breeding of ideal-type rice.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.34 no.3
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• pp.339-345
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• 1998

The purpose of this paper is to investigate the effect of the specimen geometries on the pin bearing strength of the angle ply carbon fiber reinforced composites. The effect of the edge distance and the specimen width on the pin bearing strength of angle ply CFRP composites are experimentally investigated in this paper. As results, the failure mode and pin bearing strength of mechanical joints turned out to depends on the stacking sequence and specimen geometries such as the edge distance and the specimen width. The higher pin bearing strength obtained for the angle ply CFRP composites is attributed to a combination of debonding, pull out, buckling and breakage of fiber and also the matrix cracking.

• KIEAE Journal
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• v.2 no.3
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• pp.33-38
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• 2002

The intermediate range of temperatures($100{\sim}300^{\circ}C$) which can be achieved with CPCs(Compound Parabolic Concentrators) without tracking device provides both economic and thermal advantages for solar collector design. The present paper summarizes critical design considerations for CPC with cylindrical absorber and its optical performance using ray tracing program. Concentration ratios vary as acceptance half angle, ratio of reflector height to aperture width and ratio of reflector area to aperture area. This effects showed that the concentration ratio was increased as acceptance angle but optimum ratio of reflector height to aperture width existed at critical value. As a result of ray tracing, solar ray losses was maximized at acceptance half angle and this problem was solved by increasing absorber tube diameter. The concentrating flux distribution on the absorber surface was uniform but peak flux existed.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 1996.11a
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• pp.56-60
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• 1996

An experimental study on the grinding temperature and Acoustic Emission(AE) signals due to the different shapes of wheel was conducted. The grinding characteristics by slotted shapes of wheel changed by width and helical angle, were compared with those by general one. Lower grinding temperature was obtained for 30$^{\circ}$ helical angle with 10mm width, Root Mean Square(RMS) values of AE signals were higher for slotted wheel rather than general one.

• Proceedings of the Korean Society of Machine Tool Engineers Conference
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• 2002.10a
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• pp.324-328
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• 2002

Recently, in machining industry much progress has been made by taking advantage of high speed machining. On the other hand as disadvantage high speed machining involves shortening the life of cutting tool. In this research we want to evaluate the performance of appropriate endmill for high speed machining in accordance with surface roughness of land width and clearance angle of flat-endmill