• The Journal of Korean Academy of Prosthodontics
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• v.59 no.1
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• pp.18-26
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• 2021

Purpose: Generally, patients are noticed to store denture in water when removed from the mouth. However, few studies have reported the advantage of volumetric change in underwater storage over dry storage. To be a reference in defining the proper denture storage method, this study aims to evaluate the volumetric change and dimensional deformation in case of underwater and dry storage. Materials and methods: Definitive casts were scanned by a model scanner, and denture bases were designed with computer-aided design (CAD) software. Twelve denture bases (upper 6, lower 6) were printed with 3D printer. Printed denture bases were invested and flasked with heat-curing method. 6 upper and 6 lower dentures were divided into group A and B, and each group contains 3 upper and 3 lower dentures. Group A was stored dry at room temperature, group B was stored underwater. Group B was scanned at every 24 hours for 28 days and scanned data was saved as stereolithography (SLA) file. These SLA files were analyzed to measure the difference in volumetric change of a month and Kruskal-Wallis test were used for statistical analysis. Best-fit algorithm was used to overlap and 3-dimensional color-coded map was used to observe the changing pattern of impression surface. Results: No significant difference was found in volumetric changes regardless of the storage methods. In dry-stored denture base, significant changes were found in the palate of upper jaw and posterior lingual border of lower jaw in direction away from the underlying tissue, maxillary tuberosity of upper jaw and retromolar pad area of lower jaw in direction towards the underlying tissue. Conclusion: Storing the denture underwater shows less volumetric change of impression surface than storing in the dry air.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.37 no.8
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• pp.1035-1041
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• 2013

To evaluate the structural integrity and dynamic characteristic of the knuckle part of a KTX anti-roll bar, an experimental and a numerical approach were used in this study. In the experimental approach, the acceleration and strain data for the knuckle parts of the KTX and KTX-SANCHUN anti-roll bar were respectively measured to evaluate and compare its structural dynamic characteristics under the operating environments of the Honam line. In the numerical approach, the evaluation of its structural integrity was conducted using LS-DYNA 3D, and then, the reliability of the finite element model used was ensured by a comparative evaluation with the experiment. The numerical results showed that the stress and velocity field of the knuckle part composed of a layered structure of a thin steel plate and rubber were more moderate than those of the knuckle part made of only a thick steel block owing to the reduction of relative contact between the knuckle and the connecting rod. It was found that the knuckle part made of a thin steel plate and rubber was recommended as the best solution to improve its structural integrity resulting from the elastic behavior of the KTX anti-roll bar being enabled under a repeating external force.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2013.04a
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• pp.835-841
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• 2013

Modern solid-state gyroscopes (HRG) with hemispherical resonators from high-purity quartz glass and special surface superfinishing and ultrathin gold coating become the best instruments for precise-grade inertial reference units (IRU) targeting long-term space missions. Designing of these sensors could be a notable contribution into development of Korea as a space nation. In participial, 40mm diameter thin-shell resonator from high-purity fused quartz, fabricated as a single-piece with its supporting stem has been designed, machined, etched, tuned, tested, and delivered by STM Co. (ATS of Ukraine) several years ago; an extremely-high Q-factor (upto 10~20 millions) has been shown. Understanding of the best way how to match such a unique sensor with inner glass assembly of the gyro means how to use the high potential in a maximal extent; and this has become the urgent task. Inner quartz glass assembly has a very thin indium (In) layer soldered the resonator and its silica base (case), but effects of internal resonances between operational modal pair of the shell-cup and its side (parasitic) modes can notable degrade the potential of the sensor as a whole, instead of so low level of resonator's intrinsic losses. Unfortunately, there are special combinations of dimensions of the parts (so-called, "resonant sizes"), when intensive losses of energy occurs. The authors proposed to use the length of stem's fixture as an additional design parameter to avoid such cases. So-called, a cyclic scheme of finite element method (FEM) and ANSYS software were employed to estimate different combinations of gyro assembly parameters. This variant has no mismatches of numerical origin due to FEM's discrete mesh. The optimum length and dangerous "resonant lengths" have been found. The special attention has been paid to analyses of 3D effects in a cup-stem transient zone, including determination of a difference between the positions of geometrical Pole of the resonant hemisphere and of its "dynamical Pole", i.e., its real zone of oscillation node. Boundary effects between the shell (cup) and 3D short "beams" (inner and outer stems) have been ranged. The results of the numerical experiments have been compared with the classic model of a quasi-hemispherical shell band with inextensional midsurface, and the solution using Rayleigh's functions of the $1^{st}$ and $2^{nd}$ kinds. To guarantee the truth of the recommended sizes to a designer of the real device, the analytical and FEM results have been compared with experimental data for a party of real resonators. The consistency of the results obtained by different means has been shown with errors less than 5%. The results notably differ from the data published earlier by different researchers.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.41 no.4
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• pp.461-468
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• 2021

The role of drones is increasing day by day in smart construction that manages construction sites with 3D data in every life cycles. This is because both the digital surface model (DSM) and the orthoimage obtained for the construction site through the drone are made of point cloud data. This study aims to develop standard work types for drone use in order to systematically utilize drones in expressway construction sites. For the study, two expressway construction sites in Korea were set as test beds, and construction types applicable to drones were derived and verified through a pilot project. As a result of the study, three construction work types were developed for road planning, road design and maintenance, respectively, and in road construction, twenty-one detailed construction types were developed for five construction work types. It is expected that drones can be used more systematically not only at expressway construction sites, but also at other road construction sites by utilizing the "standard work type at expressway construction site for drone use" developed in this study.

• Journal of Gastric Cancer
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• v.21 no.2
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• pp.191-202
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• 2021

Purpose: A near-infrared (NIR) fluorescence imaging is a promising tool for cancer-specific image guided surgery. Human epidermal receptor 2 (HER2) is one of the candidate markers for gastric cancer. In this study, we aimed to synthesize HER2-specific NIR fluorescence probes and evaluate their applicability in cancer-specific image-guided surgeries using an animal model. Materials and Methods: An NIR dye emitting light at 800 nm (IRDye800CW; Li-COR) was conjugated to trastuzumab and an HER2-specific affibody using a click mechanism. HER2 affinity was assessed using surface plasmon resonance. Gastric cancer cell lines (NCI-N87 and SNU-601) were subcutaneously implanted into female BALB/c nu (6-8 weeks old) mice. After intravenous injection of the probes, biodistribution and fluorescence signal intensity were measured using Lumina II (Perkin Elmer) and a laparoscopic NIR camera (InTheSmart). Results: Trastuzumab-IRDye800CW exhibited high affinity for HER2 (K_D=2.093(3) pM). Fluorescence signals in the liver and spleen were the highest at 24 hours post injection, while the signal in HER2-positive tumor cells increased until 72 hours, as assessed using the Lumina II system. The signal corresponding to the tumor was visually identified and clearly differentiated from the liver after 72 hours using a laparoscopic NIR camera. Affibody-IRDye800CW also exhibited high affinity for HER2 (K_D=4.71 nM); however, the signal was not identified in the tumor, probably owing to rapid renal clearance. Conclusions: Trastuzumab-IRDye800CW may be used as a potential NIR probe that can be injected 2-3 days before surgery to obtain high HER2-specific signal and contrast. Affibody-based NIR probes may require modifications to enhance mobilization to the tumor site.

• Journal of the Korean GEO-environmental Society
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• v.13 no.11
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• pp.37-42
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• 2012

This study investigated the use of Geobacter lovleyi with TBOS(Tetrabutoxysilane) for TCE(Trichloroethylene) dechlorination. The TCE dechlorination by Geobacter lovleiy was mathematically described as the independent variables such as initial concentration of TCE, protein mass of Geobacter lovleyi and initial concentration of TOBS, and these were modeled by the use of response surface methodology(RSM). These experiments were carried out as a Box-Behnken Design(BBD) consisting of 15 experiments. The application of RSM yielded the following equation, which is empirical relationship for the dechlorination efficiency($Y_1$, %) of TCE and first order kinetic constant of TCE($Y_2,\;d^{-1}$) by independent variables in coded unit : $Y_1=-11.50X_1$(initial concentration of TCE) + $4.25X_2$(protein mass as Geobacter lovleyi injected mass) - $4.75X_3$(initial concentration of TBOS) - ${6.58X_1}^2$ - ${8.58X_2}^2$ + 93.67, $Y_2=-10.92X_1+5.06X_2-4.89X_3-{4.93X_3}^2-2.19X_1X_2+2.54X_1X_3-2.19X_2X_3+16.71$. In this case, the value of the adjusted determination coefficient(adjusted $R^2$= 0.975 and 0.934) were closed to 1, showing a high significance of the model. Statistical results showed the order of TCE dechlorination at experimental factors to be initial TCE concentration > initial TBOS concentration > protein mass, but the interaction effects were non-significant.

• Korean Journal of Applied Biomechanics
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• v.21 no.4
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• pp.437-447
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• 2011

In this study, the lower limbs joints were analyzed for features based on the biomechanical characteristics of landing techniques according to height and landing on the ground type (flats and downhill). In order to achieve the objectives of the study, changes were analyzed in detail contents such as the height and form of the first landing on the ground at different angles of joints, torso and legs, torso and legs of the difference in the range of angular motion of the joint, the maximum angular difference between joints, the lower limbs joints difference between the maximum moment and the difference between COM changes. The subjects in this study do not last six months did not experience joint injuries 10 males in 20 aged were tested. Experimental tools to analyze were the recording and video equipment. Samsung's SCH-650A model camera was used six units, and the 2 GRF-based AMTI were used BP400800 model. 6-unit-camera synchronized with LED (photo cell) and Line Lock system were used. the output from the camera and the ground reaction force based on the data to synchronize A/D Syc. box was used. To calculate the coordinates of three-dimensional space, $1m{\times}3m{\times}2m$ (X, Y, Z axis) to the size of the control points attached to the framework of 36 markers were used, and 29 where the body was taken by attaching a marker to the surface. Two kinds of land condition, 40cm and 60cm in height, and ground conditions in the form of two kinds of flat and downhill slopes ($10^{\circ}$) of the landing operation was performed and each subject's 3 mean two-way RM ANOVA in SPSS 18.0 was used and this time, all the significant level was set at a=.05. Consequently, analyzing the landing technique as land form and land on the ground, the changes of external environmental factors, and the lower limbs joints' function in the evaluation were significantly different from the slopes. Landing of the slop plane were more load on the joints than landing of plane. Especially, knee extensor moment compared to the two kinds of landing, slopes plane were approximately two times higher than flat plane, and it was statistical significance. Most of all not so much range of motion and angular velocity of the shock to reduce stress was important. In the further research, front landing as well as various direction of motion of kinetic, kinetic factors and EMG variables on lower limbs joints of the study in terms of injury-prevention-approach is going to be needed.

• Journal of Korean Tunnelling and Underground Space Association
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• v.8 no.2
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• pp.151-163
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• 2006

Although various methods for effective modeling of pre-reinforced zones have been suggested for numerical analysis of large section tunnels, tunnel designers refer to empirical cases and literature reviews rather than engineering methods because ones who use commercial programs are unfamiliar with a macro-scale approach in general. Therefore, this paper suggests a simple micro-scale approach combined with the macro-scale approach to determine equivalent design parameters for effective numerical modeling of pre-reinforced zones in tunnel. This new approach is to determine the equivalent stiffness of pre-reinforced zones with combination of ground, bulb, and steel in series or/and parallel. For verification, 3-D numerical results from the suggested approach are compared with those of a realistic model. The comparison suggests that two cases make best approximation to a realistic solution: One is related to the series-parallel stiffness system (hereafter SPSS) in which bulb and steel are coupled in parallel and then connected to the ground in series, and the other is the series stiffness system (hereafter SSS) in which only bulb and steel are coupled in series. The SPSS is recommended for stiffness calculation of pre-reinforced zones because the SSS is inconvenient and time-consuming. The SPSS provides slightly bigger vertical displacement at tunnel crown in weathered rock than other cases and give almost identical results to a realistic model for horizontal displacement at tunnel spring line and ground surface settlement. Displacement trends on weathered rock and weathered soil are similar. The SPSS which is suggested in this paper represents the behavior mechanism of pre-reinforced area effectively.

• Journal of the Korean earth science society
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• v.32 no.6
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• pp.640-653
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• 2011

We simulate the propagation of earthquake waves in the continental margin of Antarctica using the elastic wave modeling algorithm, which is modified to be suitable for acoustic-elastic coupled media and earthquake source. To simulate the various types of earthquake source, the staggered-grid finite-difference method, which is composed of velocity-stress formulae, can be more appropriate to use than the conventional, displacement-based, finite-difference method. We simulate the elastic wave propagation generated by earthquakes combining 3D staggered-grid finite-difference algorithm composed of displacement-velocity-stress formulae with double couple mechanisms for earthquake source. Through numerical tests for left-lateral strike-slip fault, normal fault and reverse fault, we could confirm that the first arrival of P waves at the surface is in a good agreement with the theoretically-predicted results based on the focal mechanism of an earthquake. Numerical results for a model made after the subduction zone in the continental margin of Antarctica showed that earthquake waves, generated by the reverse fault and propagating through the continental crust, the oceanic crust and the ocean, are accurately described.

• The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
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• v.10 no.1
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• pp.56-68
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• 2005

We measured nitrate and other nutrients in sediment pore waters retrieved from three sites at the southern upper-tidal flats of the Ganghwa Island. Denitrification rate is estimated by applying a simple 1-D model to the nitrate profiles. Results from Jangwha and Dongmak sites are $7.8{\sim}9.4{\times}10^{-7}{\mu}mol{\cdot}cm^{-2}{\cdot}sec^{-1}$, and $1.4{\sim}3.6{\times}10^{-7}{\mu}mol{\cdot}cm^{-2}{\cdot}sec^{-1}$, respectively. Rates are comparable to those reported around the world in an order of magnitude. Denitrification was lower in summer. The rates were about 1.5 times higher at site where the surface sediments consist of relatively coarser particles. This implies that particle size would control the reactant supply to the subsurface sediment. One may claim the denitrification as an evidence of the biogeochemical purification function of tidal flat. However, the purification seems not a general attribute of a tidal flat when whole system is scrutinized by a thermodynamic criterion. Currently the term 'tidal flat' is used when describing the diverse coastal wetlands such as salt marshes, sandy tidal flats and muddy tidal flats, which exhibit quite different ecological functions. Thus it is worthy of mentioning that the classification of coastal wetlands on the basis of sedimentological characteristics and biogeochemical functions should facilitate our understanding.