• Journal of the Geological Society of Korea
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• v.54 no.6
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• pp.631-640
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• 2018

To understand the formation and evolution of a sedimentary basin in basin analysis and modelling studies, it is important to analyze the thickness and age range of sedimentary layers infilling a basin. Because the compaction effect reduces the thickness of sedimentary layers during burial, basin modelling studies typically restore the reduced thickness using the relation of porosity and depth (compaction trend). Based on the compilation plots of published compaction trends of representative sedimentary rocks (sandstone, shale and carbonate), this study estimates the compaction trend ranges with exponential curves and equations. Numerical analysis of sedimentary compaction is performed to evaluate the variation of porosity and layer thickness with depth at key curves within the compaction trend ranges. In sandstone, initial porosity lies in a narrow range and decreases steadily with increasing depth, which results in relatively constant thickness variations. For shale, the porosity variation shows two phases which are fast reduction until ~2,000 m in depth and slow reduction at deeper burial, which corresponds to the thickness variation pattern of shale layers. Carbonate compaction is characterized by widely distributed porosity values, which results in highly varying layer thickness with depth. This numerical compaction analysis presents quantitatively the characteristics of porosity and layer thickness variation of each lithology, which influence on layer thickness reconstruction, subsidence and thermal effect analyses to understand the basin formation and evolution. This work demonstrates that the compaction trend is an important factor in basin modelling and underlines the need for appropriate application of porosity data to produce accurate analysis outcomes.

• The Journal of Advanced Prosthodontics
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• v.13 no.4
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• pp.226-236
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• 2021

PURPOSE. This study aimed to evaluate the effect of incorporating zirconium oxide nanoparticles (nano-ZrO₂) in polymethylmethacrylate (PMMA) denture base resin on flexural properties at different material thicknesses. MATERIALS AND METHODS. Heat polymerized acrylic resin specimens (N = 120) were fabricated and divided into 4 groups according to denture base thickness (2.5 mm, 2.0 mm, 1.5 mm, 1.0 mm). Each group was subdivided into 3 subgroups (n = 10) according to nano-ZrO₂ concentration (0%, 2.5%, and 5%). Flexural strength and elastic modulus were evaluated using a three-point bending test. One-way ANOVA, Tukey's post hoc, and two-way ANOVA were used for data analysis (α = .05). Scanning electron microscopy (SEM) was used for fracture surface analysis and nanoparticles distributions. RESULTS. Groups with 0% nano-ZrO₂ showed no significant difference in the flexural strength as thickness decreased (P = .153). The addition of nano-zirconia significantly increased the flexural strength (P < .001). The highest value was with 5% nano-ZrO₂ and 2 mm-thickness (125.4 ± 18.3 MPa), followed by 5% nano-ZrO₂ and 1.5 mm-thickness (110.3 ± 8.5 MPa). Moreover, the effect of various concentration levels on elastic modulus was statistically significant for 2 mm thickness (P = .001), but the combined effect of thickness and concentration on elastic modulus was insignificant (P = .10). CONCLUSION. Reinforcement of denture base material with nano-ZrO₂ significantly increased flexural strength and modulus of elasticity. Reducing material thickness did not decrease flexural strength when nano-ZrO₂ was incorporated. In clinical practice, when low thickness of denture base material is indicated, PMMA/nano-ZrO₂ could be used with minimum acceptable thickness of 1.5 mm.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.48 no.1
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• pp.51-58
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• 2012

As a basic study to improve hooking ability of long line fishing gear, which is widely used around Jeju-do coast, the researcher performed hooking experiment of parrot fish by manufacturing and installing 7 kinds of model long line fishing gears, whose thickness of branch line are different and 8 kinds of model long line fishing gear, whose length of branch line are different, in indoor circular aquarium, which is installed for the model experiment of thickness and length of branch line that are various by fishing implement and improper. The hooking rate depending on thickness and length of branch line was calculated and the effect of thickness and length of branch line on hooking rate was analyzed. Its results are as follows. When branch line was thin and long, high hooking rate appeared. In the scope of value setting, the relationship between thickness ($B_t$) of branch line and total hooking rate ($Th_r$) can be shown as following formula as. In the scope of value setting, the relationship between length ($B_t$) of branch line and total hooking rate ($B_t$) can be shown as $Th_r=-20.83B_t+26.04$. Through Pearson correlation analysis, the coefficient of correlation between thickness of branch line and hooking rate was -0.718. Therefore it showed significance in 0.01 significance level. Through Pearson correlation analysis, the coefficient of correlation between length of branch line and hooking rate was 0.431. Therefore it showed significance in 0.01 significance level.

• Journal of the Microelectronics and Packaging Society
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• v.19 no.3
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• pp.57-62
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• 2012

In this paper, numerical analysis by finite element method, parameter design by the Taguchi method and ANOVA method were used to analyze about effect of design deviations and thickness variations on warpage of FCCSP substrate. Based on the computed results, it was known that core material in substrate was the most determining deviation for reducing warpage. Solder resist, prepreg and circuit layer were insignificant effect on warpage relatively. But these results meant not thickness effect was little importance but mechanical properties of core material were very effective. Warpage decreased as Solder resist and circuit layer thickness decreased but effect of prepreg thickness was conversely. Also, these results showed substrate warpage would be increased to maximum 40% as thickness deviation combination. It meant warpage was affected by thickness tolerance under manufacturing process even if it were met quality requirements. Threfore, it was strongly recommended that substrate thickness deviation should be optimized and controlled precisely to reduce warpage in manufacturing process.

• Proceedings of the Korean Vacuum Society Conference
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• 2016.02a
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• pp.196.1-196.1
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• 2016

TCO(Transparent Conducting Oxide) on flat glass is used in thin-film photovoltaic cell, flat-panel display. Nowadays, Corning(R) Willow Glass(R), known as flexible substrate, has attracted much attention due to its many advantages such as reliable roll-to-roll glass processing, high-quality flexible electronic devices, high temperature process. Also, it can be an alternative to flexible polymer substrates which have their poor stability and degradation of electrical and optical qualities. For application on willow glass, the flexibility, electrical, optical properties can be greatly influenced by the TCO thin film thickness due to the inherent characterization of thin film in nanoscale. It can be expected that while thick TCO layer causes poor transparency, its sheet resistance become low. Also, rarely reports were focusing on the influence of flexible properties by varying TCO thickness on flexible glass. Therefore, it is very important to optimize TCO thickness on flexible Willow glass. In this study, Ti-ZnO thin films, with different thickness varied from 0 nm to 50 nm, were deposited on the flexible willow glass by atomic layer deposition (ALD). The flexible, electrical and optical properties were investigated, respectively. Also, these properties of Ti-doped ZnO thin films were compared with un-doped ZnO thin film. Based on the results, when Ti-ZnO thin films thickness increased, resistivity decreased and then saturated; transmittance decreased. The Figure of Merit (FoM) and flexibility was the highest when Ti-ZnO thickness was 40nm. The flexible, electrical and optical properties of Ti-ZnO thin films were better than ZnO thin film at the same thickness.

• The Journal of Korean Physical Therapy
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• v.27 no.5
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• pp.281-286
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• 2015

Purpose: The study was to determine whether mechanical horseback-riding training according to velocity may improve trunk muscles thickness in healthy adults. Methods: Twenty healthy adults participated in this study. The subjects were divided into 2 groups as follows: 10 subjects in high velocity mechanical horseback-riding training (MHRT) and 10 subjects in low velocity MHRT. Subjects in all groups performed a total of 18 sessions 3 times a day for 20 minutes and this experiment lasted for 6 weeks. Mann-Whitney and Wilcoxon Signed Rank test were used in analysis the results of trunk muscle thickness. Ultrasonography was performed to evaluate for thickness of rectus abdominis (RA), external oblique (EO), internal oblique (IO), transverse abdominis (TrA), erector spine (ES), and multifidus (MF) in trunk muscles. Results: Results on the changes of EO, IO, and ES of high velocity MHRT showed a significant increase after 6 weeks (p<0.05). Regarding the changes of EO, IO, ES, TrA, and MF of low velocity MHRT, a significant increase was observed after 6 weeks (p<0.05). The differences in change of trunk muscle thickness before training, after 6-week training between groups, TrA and MF of low velocity MHRT were significantly higher (p<0.05). Conclusion: Based on the results of the current study, the velocity of MHRT was shown to affect change of trunk muscle thickness in healthy adults. In particular, low velocity MHRT may serve as a useful method to provide for TrA, MF thickness improvement related to trunk stabilizers.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2008.04a
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• pp.27-28
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• 2008

We have studied an organic layer-thickness dependent electrical and optical properties of organic light-emitting diodes in a device structure of ITO/TPD/$Alq_3$/LiF/Al. While a hole-transport layer thickness of TPD was varied from 35 to 65nm, an emissive layer thickness of $Alq_3$ was varied from 50 to 100nm. A ratio of those two layers was kept to about 2:3. Variation of the layer thickness changes a traverse time of injected carriers across the organic layer, so that it may affect on the chance of probability of exciton formation. Current-voltage-luminance characteristics of the devices show that there are typical rectifying behaviors, and the luminance reaches about $30,000cd/m^2$. Thickness-dependent current efficiency shows that there is a gradual increase of the efficiency as the total layer thickness increases. The efficiency becomes saturated to be about 10cd/A when the total thickness is above 140nm. They show that emission was from the $Alq_3$ layer, because the peak wavelength is about 525nm. View angle-dependent emission spectra show that the emission intensity decreases as the angle increases.

• The Journal of Korean Academy of Prosthodontics
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• v.34 no.1
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• pp.151-167
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• 1996

Temporary soft liners can be used to prevent chronic soreness from dentures or to aid in its treatment are as adjuncts in tissue conditioning, for temporary obturators, and to stabilize baseplate or surgical stent. The purpose of this study was to evaluate the shock absorption properties of several temporary soft denture liners using a free drop test with an accelerometer. The materials tested inclued Coe-comfort, Softone, Tissue conditioner and Viscogel. The specimens were fabricated with the thickness of 1, 2, 3mm and were stored in distilled water at $37^{\circ}C$ for a day, 1, 2, and 3 weeks. Six samples were made with each material for each test condition and the shock-absorbing behavior was evaluated according to material, thickness and duration. The results were as following : 1. Softone of 3mm thickness stored for a day showed the most excellent shock absorbability. 2. The shock absorbing behavior of duration according to materials and thickness showed a day to be the highest and decreased in 1 week, 2 weeks and 3 weeks in that order(p<0.05). And there was no significant difference between durations in Tissue conditioner. 3. The shock absorbability of thickness according to materials and duration showed 3mm to be highest and decreased in the order of 2mm, 1mm(p<0.05). 4. In comparison of the shock absorbability of temporary soft denture liners according to thickness, there was statistically significant difference between Softone and Visocgel, Tissue conditioner, Coe-comfort / Viscogel and Tissue conditioner, Coe-comfort in 1,2mm thickness, and between Softone, Viscogel and Tissue conditioner, Coe-comfort in 3mm thickness (p<0.05).

• Transactions of the Korean Society of Mechanical Engineers B
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• v.26 no.6
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• pp.893-901
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• 2002

Effect of boundary layer thickness on the flow characteristics around a rectangular prism has been investigated by using a PIV(Particle Image Velocimetry) technique. Three different boundary layers(thick, medium and thin)were generated in the Atmospheric Boundary Layer Wind Tunnel at Pusan National University. The thick boundary layer having 670 mm thickness was generated by using spires and roughness elements. The medium thickness of boundary layer($\delta$=270 mm) was the natural turbulent boundary layer at the test section floor with fairly long developing length(18 m). The thin boundary layer($\delta$=36.5 mm) was generated on the smooth panel elevated 70cm from the wind tunnel floor. The Reynolds number based on the free stream velocity(3 ㎧) and the height of the model(40 mm) was 7.9$\times$10$^3$. The mean velocity vector fields and turbulent kinetic energy distributions were measured and compared. The effect of boundary layer thickness was clearly observed not only in the length of separation bubble but also in the location of reattachment point. The thinner the boundary layer thickness, the higher the turbulent kinetic energy Peak around the model roofbecame. It is strongly recommended that the height ratio between the model and the approaching boundary layer thickness should be encountered as a major parameter.

• The Journal of Korean Physical Therapy
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• v.28 no.2
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• pp.112-118
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• 2016

Purpose: This study examined thickness changes in abdominal muscles according to difficulty level of core stabilization exercise in healthy subjects. Methods: Thirty healthy subjects (age range: 21-30 years) volunteered under three conditions. In the first condition, the subjects performed an abdominal draw-in maneuver (ADIM). In the second condition, they performed the ADIM during quadruped exercise using a suspension device without extending their lower limbs. In the third condition, the subjects performed the ADIM during quadruped exercise using a suspension device while extending both lower limbs. The changes in thickness of transverse abdominis (TrA), internal oblique (IO), and external oblique (EO) muscles were measured by ultrasonography (US) imaging during the three experimental conditions, and US was used to measure the improvement ratio of muscle thickness at rest. The interventions were conducted over three trials in each condition, and measurements were performed on each subject by one examiner. Results: Our results showed a significantly greater increase in the muscle thickness of TrA and IO muscles after performance of quadruped exercise using a suspension device without knee extension (p<0.05) compared to the other conditions. The results also showed a significantly greater increase in the thickness changes of EO muscle in those who performed the ADIM during quadruped exercise using a suspension device with knee extension (p<0.05) compared with the ADIM only. Conclusion: These findings demonstrated positive evidence that a low-level core stabilization exercise could improve thickness of abdominal muscles.