• Journal of the Korean Crystal Growth and Crystal Technology
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• v.28 no.3
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• pp.123-129
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• 2018

Ink-jet printing technology with ceramic ink of the four digital primary colors (cyan, magenta, yellow, and black; CMYK) can provide stable coloration even in the high-temperature firing process. Ceramic ink-jet printing can be widely applied in construction and ceramic industries due to the advantages of accurate and fast printing process of digital images for various products. Generally, organic solvent with proper viscosity and surface tension has been used in digital ink-jet printing process. However, the needs of ceramic ink without VOCs emission is increasing. In the present study, eco-friendly ceramic ink was synthesized by combining alumino boro-silicate glass frit and $CoAl_2O_4$ inorganic pigment based on an aqueous solvent that does not generate VOCs. The rheological properties and dispersion stability of aqueous ceramic ink were optimized. Jetting behavior and printing characteristics of the ceramic ink were also investigated in detail. As a result, the formulated aqueous ceramic complex ink showed a suitable jetting behavior without satellite drop by adjusting viscosity and surface tension. The ceramic ink can be printed on glass substrate with minimized spreading phenomena duo to high contact angle.

• Journal of the Korean Geotechnical Society
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• v.15 no.2
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• pp.105-127
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• 1999

Application of the soil nailing method is continuously extended in maintaining stable excavations and slopes. Occasionally, however, ground anchor support system may not be used because of space limitations in urban excavation sites nearby the existing structures. In this case, soil nailing system with relatively short length of nails could be efficiently adopted as an alternative method. The general soil nailing support system, however, may result in excessive deformations particularly in an excavation zone of the existing weak subsoils. Pretensioning the soil nails then, could play important roles in reducing deformations mainly in an upper part of the nailed-soil excavation system as well as improving local stability. In the present study, the analytical procedure and design technique are proposed to evaluate maximum pretension force and stability of the pretensioned soil nailing system. Also proposed are techniques to determine the required thickness of a shotcrete facing and to estimate probability of a failure against the punching shear. The predicted results are compared with the limited measurements obtained from the excavation site constructed by using the pretensioned soil nails. Based on the proposed procedure and technique, effects of the radius of a influence circle and dilatancy angle on the thickness of a shotcrete facing, bonded length and safety factors are analyzed. In addition, effects of the reduction of deformations expected by pretensioning of the soil nails are examined in detail throughout an illustrative example and FLAC$^{2D}$ program analysis.s.

• Korean journal of applied entomology
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• v.24 no.4 s.65
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• pp.231-238
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• 1986

Molecular orbital theoretical study on the stability of conformations and chemical reactivity of 0,0-diethylphenylphosphate derivatives were carried out by EHT and CNDO/2 molecular orbital calculation method. The results shown that the dipole moment(${\mu}$) and total energies of the ${\theta}=90^{\circ}$ conformer were ${\mu}=3.185D\;&\;E_t=-162.6479(au)$ and also that of the ${\theta}=0^{\circ}$ conformer were ${\mu}=5.596D\;&\;E_t=-162.4013(au)$, respectively. Therefore, the values of ${\mu}\;&\;E_t$ of the ${\theta}=90^{\circ}$ conformer were much smaller than that of the ${\theta}=0^{\circ}$ conformer. The form with angle of rotation ${\theta}=90^{\circ}$ of phenyl ring was shown to be most stable and this was interpreted in terms of electrostatic and steric effect. 0,0-diethylphenylphosphate derivatives are predicted to increase both charge and orbital controlled $SN_2$ reactivity of the electron withdrawing substituent reduces the HOMO & LUMO energy, while the electron withdrawing substituent due to increase in positive charge of phosphorus atom of phosphate molecule.

• Journal of the Korean Society of Marine Environment & Safety
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• v.20 no.4
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• pp.443-450
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• 2014

In this study, we have discussed about the effect of hydrofoil arrangement and longitudinal moment characteristic on longitudinal motion stability of fully-submerged hydrofoil by the experiment of tandem hydrofoil model. First of all, tandem hydrofoil model that has canard wing arrangement has been made and characteristics of lift force and drag force by performing the lift force and drag force measuring experiment has also been estimated. Besides, tandem hydrofoil model's wing arrangement which has the initial stability and self stability of longitudinal motion has also been determined. In longitudinal stability experiment of tandem hydrofoil model, the motion characteristic of pitch and heave and the longitudinal stability of foil borne condition by variation of self stability of longitudinal moment and longitudinal distance are estimated. The result from the experiment and it's important conclusion can be described as below; Increase the self stability for longitudinal moment, the higher self stability for pitch motions in a constant pitch angles. By increasing the self stability for longitudinal moment, the range of fluctuation of pitch motion and heave motion for pitch angle also will change relatively small and longitudinal stability is excellent. Lastly, when the lift force of hydrofoil is remain constants, we can conclude that securing the enough self stability for longitudinal moment is essential for stable foil borne condition of tandem hydrofoil.

• Maxillofacial Plastic and Reconstructive Surgery
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• v.40
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• pp.35.1-35.7
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• 2018

Background: After the resection at the mandibular site involving oral cancer, free vascularized fibular graft, a type of vascularized autograft, is often used for the mandibular reconstruction. Titanium mesh (T-mesh) and particulate cancellous bone and marrow (PCBM), however, a type of non-vascularized autograft, can also be used for the reconstruction. With the T-mesh applied even in the chin and angle areas, an aesthetic contour with adequate strength and stable fixation can be achieved, and the pores of the mesh will allow the rapid revascularization of the bone graft site. Especially, this technique does not require microvascular training; as such, the surgery time can be shortened. This advantage allows older patients to undergo the reconstructive surgery. Case presentation: Reported in this article are two cases of mandibular reconstruction using the ready-made type and custom-made type T-mesh, respectively, after mandibular resection. We had operated double blind peer-review process. A 79-year-old female patient visited the authors' clinic with gingival swelling and pain on the left mandibular region. After wide excision and segmental mandibulectomy, a pectoralis major myocutaneous flap was used to cover the intraoral defect. Fourteen months postoperatively, reconstruction using a ready-made type T-mesh (Striker-Leibinger, Freibrug, Germany) and iliac PCBM was done to repair the mandible left body defect. Another 62-year-old female patient visited the authors' clinic with pain on the right mandibular region. After wide excision and segmental mandibulectomy on the mandibular squamous cell carcinoma (SCC), reconstruction was done with a reconstruction plate and a right fibula free flap. Sixteen months postoperatively, reconstruction using a custom-made type T-mesh and iliac PCBM was done to repair the mandibular defect after the failure of the fibula free flap. The CAD-CAM T-mesh was made prior to the operation. Conclusions: In both cases, sufficient new-bone formation was observed in terms of volume and strength. In the CAD-CAM custom-made type T-mesh case, especially, it was much easier to fix screws onto the adjacent mandible, and after the removal of the mesh, the appearance of both patients improved, and the neo-mandibular body showed adequate bony volume for implant or prosthetic restoration.

• Journal of the Korean Geotechnical Society
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• v.31 no.12
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• pp.71-76
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• 2015

Recently, people are increasingly interested in horizontal directional drilling (HDD) to construct oil and gas pipeline and utility pipeline in the urban area as one of trenchless methods. One of major issues during the HDD is the collapse of borehole, which may be the potential causes of ground collapse. This study investigated the effect of mud pressure on the borehole stability, using finite element analysis. Since the borehole is being drilled with a certain angle, three dimensional analysis should be performed. The borehole stability was examined by applying two different types of mud pressures, i.e., uniform and non-uniform, to the exterior surface of borehole. The results show that the high mud pressure at the beginning of drilling, i.e., at shallow depth, causes the borehole collapse, whereas the borehole was stable even at high mud pressure as the drilling depth increases. It can be said that the determination of maximum mud pressure is strongly related to the drilling depth.

• Korean Journal of Applied Biomechanics
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• v.15 no.3
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• pp.21-30
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• 2005

The purpose of this study is helps to make full use for perfect performance by grasping the defects of Tichonkich motion performed by athlete CSM For this, the study analyzed kinematical variables through Tichonkich motions performed at the first selection competition(1st trial) and final selection competition(2nd trial) for the dispatch to the 28th Athens Olympic Games using the three-dimensional cinematographical method with a high-speed video camera, and obtained the following results. 1. During Tichonkich motion, the execution time of up swing and the right hand moving to the left bar was shorter in the 2nd trial than the 1st one, while the execution time of down swing, the support of the left bar and the right hand moving to the right bar was longer in the 2nd trial than the 1st trial. 2. The horizontal position of COG in the 2nd trial was -35cm in the 1st stage, 42cm in the 3rd stage and 29cm in the 4th stage, that is, it showed a great swing focused on the circular movement compared to the 1st trial, while the vertical position of COG was -59cm in the 2nd stage, that is, it showed a small swing focused on a up and down movement. Also the 5th stage vertical position was 98cm, and the 6th stage vertical position was 95cm in the 2nd trial which were higher than those of the 1st trial, so it has provided magnificence required in the modern gymnastics. 3. And it was indicated that the horizontal velocity at the down swing phase proceeded forward more rapidly in the 2nd trial than that in the 1st trial, and the reverse ascent made a rapid vertical rise lessening left and right velocity change. And in the 5th stage, the 2nd trial was kept very slower in horizontal, vertical and left and right velocity that in the 1st trial, so it reached a handstand with leisurely movement. 4. In the 2nd trial, shoulder joint of the 1st, 2nd, 3rd stages kept a larger angle than that in the 1st trial, that is, it made a great swing while in the 1st trial, it showed a swing movement dependent on kick movement by the flexion and extension of hip joint. Also in the 2nd trial, the body formed a vertical posture with both hands supporting the left bar and hip joint was kept larger as $198^{\circ}$ and $190^{\circ}$ in the 5th and 6th stage than that in the 1st trial, so it made a handstand with the body uprightly stretched out, and magnificent and stable movement.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.20 no.6
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• pp.472-482
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• 2019

This paper describes the stabilization of underwater TAS winch system Deploy/Recover operation performance. TAS winch installed on the stern of submarine performs to deploy/recover sensor, towing cable and rope tail which is deployed from the stern and separated from submarine itself. Also TAS winch provides transmission path of power to the sensor and data transmitting/receiving path which data are acquired from underwater environment like sound, depth and temperature. At the step of TAS winch evaluation test, sporadic standstill and rotating speed oscillation phenomenon were occurred. Winch motor provides the available torque to deploy/recover TAS and root cause analysis to the winch motor was done to find exact reason to sporadic malfunction. When winch motor was disassembled, eccentricity of rotor, slip-ring and the other composition part for winch motor were found. These might cause magnetic field distortion. To make TAS winch system more stable and block magnetic field distortion, this paper suggests methods to enhance fixing status installed in winch motor. For reliable data acquisition for TAS winch operation, the deploy/recover function of the improved type of TAS winch was verified in LBTS making similar condition with sea status. At the end of stage, improved type of TAS winch was tested on some functions not only deploy/recover function, but sustainability of TAS operation on specific velocity, steering angle of submarine in the sea trial. Improved type of TAS winch was verified in accordance with design requirement. Also, validity of suggested methods were verified by the sea trial.

• Korean Journal of Remote Sensing
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• v.34 no.6_4
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• pp.1545-1553
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• 2018

Recent eruptive activity at Kīlauea Volcano started on at the end of April in 2018 showed rapid ground deflation between May and June in 2018. On summit area Halema'uma'u lava lake continued to drop at high speed and Kīlauea's summit continued to deflate. GPS receivers and electronic tiltmeters detected the surface deformation greater than 2 meters. We explored the time-series surface deformation at Kīlauea Volcano, focusing on the early stage of eruptive activity, using multi-temporal COSMO-SkyMed SAR imagery. The observed maximum deformation in line-of-sight (LOS) direction was about -1.5 meter, and it indicates approximately -1.9 meter in subsiding direction by applying incidence angle. The results showed that summit began to deflate just after the event started and most of deformation occurred between early May and the end of June. Moreover, we confirmed that summit's deflation rarely happened since July 2018, which means volcanic activity entered a stable stage. The best-fit magma source model based on time-series surface deformation demonstrated that magma chambers were lying at depths between 2-3 km, and it showed a deepening trend in time. Along with the change of source depth, the center of each magma model moved toward the southwest according to the time. These results have a potential risk of including bias coming from single track observation. Therefore, to complement the initial results, we need to generate precise magma source model based on three-dimensional measurements in further research.

• The Journal of Korean Academy of Prosthodontics
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• v.57 no.1
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• pp.66-74
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• 2019

Excessive wear causes many complications when untreated, so that accurate diagnosis, analysis and predictive treatment plan should be made, and through evaluation of vertical dimension and stepwise treatment, a stable inter-arch relationship can be set. For the long-term success of implant treatment, ideal position and angle of implant is important, and its importance increases especially in multiple implant cases. Therefore, thorough diagnosis and planning, accurate surgery and prosthodontic procedures are significant. In this case, a 68-year-old male patient with a loss of vertical dimension due to multiple tooth loss and overall tooth wear was planned with systematic analyses from the pre-treatment stage to rehabilitate vertical dimension. Full-mouth fixed rehabilitation with computer tomography guided implant surgery was performed to the newly set vertical dimension and attained satisfactory outcomes both functionally and esthetically.