• Journal of the Korean institute of surface engineering
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• v.53 no.3
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• pp.124-129
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• 2020

This study is for the development of high temperature ALD SiO₂ film process, optimized for gap-fill process in manufacturing memory products, using a space-divided PE-ALD system equipped with an independent control dual plasma system and orbital moving unit. Space divided PE-ALD System has high productivity, and various applications can be applied according to Top Lid Design. But space divided ALD system has a limitation to realize concentric deposition map due to process influence due to disk rotation. In order to solve this problem, we developed an orbit rotation moving unit in which disk and wafer. Also we used Independent dual plasma system to enhance thin film properties. Improve productivity and film density for gap-fill process by having deposition and surface treatment in one cycle. Optimize deposition process for gap-fill patterns with different depths by utilizing our independently controlled dual plasma system to insert N₂and/or He plasma during surface treatment, Provide void-free gap-fill process for high aspect ratio gap-fill patterns (up to 50:1) with convex curvature by adjusting deposition and surface treatment recipe in a cycle.

• Proceedings of the KIPE Conference
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• 2013.11a
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• pp.69-70
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• 2013

By using differential force between left and right wheel, lateral motion can be controlled known as Direct Yaw-moment Control (DYC). In previous researches, DYC control is proposed to increase the stability of the vehicle, but maneuverability has not been discussed sufficiently. The car handling condition which is called the index parameter of maneuverability is dependent on the vehicle velocity and steering angle. To achieve the desired vehicle's cornering path, the car handling condition must be considered sufficiently. In this paper, the novel DYC method is proposed which gives the car handling condition regardless of the longitudinal speed. The proposed controller is based on the PI controller to feedback the curvature parameter. The controlled system shows the advantages of DYC regarding to the reference trajectory by the dual motor system. With respect to the uncontrolled model, the effectiveness of the proposed method is validated by numerical examples.

• Transactions of Materials Processing
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• v.17 no.7
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• pp.491-495
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• 2008

Incremental forming path to manufacture a thick concave steel plate using the line array roll set is designed. To find the optimum forming path, the forming processes are simulated by the finite element method. A general-purpose commercial software, MSC MARC is used. A modeling with 8-node hexahedral elastic-plastic solid is performed to predict accurate springback and the analysis process was composed of 18 passes. The proposed forming paths are verified through experiments carried out in the prototype line array roll set. It is found that the process can be successfully applied to the fabrication of the dual curvature ship hull plate.

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 2008.05a
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• pp.361-364
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• 2008

Incremental forming path to manufacture a thick concave steel plate using the line array roll set is designed. To find the optimum forming path, the forming processes are simulated by the finite element method. A general-purpose commercial software, MSC.MARC is used. The rolls are modeled as rigid surfaces and the thick plate is modeled as 8-node hexahedral elastic-plastic solid elements to predict accurate springback. It is found that the process can be successfully applied to the fabrication of the dual curvature ship hull plate

• Fashion & Textile Research Journal
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• v.21 no.4
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• pp.480-487
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• 2019

This study used 3D technology to develop a multi-functional sports brassiere with increased comfort and fit that can be worn as a base layer during exercise or as underwear. A 75A size industrial lingerie figure was used to develop a standard pattern. 3D tools for scanning and pattern making, such as Vivid 910, Geomagic Design X, 2C-AN and Yuka CAD were used. The sports brassiere was designed as a tank top style with dual structure and linings attached to a pad utilized with a sport brassiere mold cup. 3D outer and lining's pattern was differently developed in consideration of the body's curvature with pad's shape and structure. Shoulder and neck part reduction rates were adjusted to increase the neck areas fit that considered the nude pattern's structure due to uncomfortableness felt by wearers who were uncomfortable with the neck areas fit on existing brand products. The reduction rate was also set differently on each part. For example, the reduction rate on outer side panel was set strongly to increase the breast's volume. Two products, developed by a 3D sports brassiere and previously released product, were worn on 8 subjects in their 20's to evaluate fit, comfort, and purchase preferences. The evaluation proved that newly developed 3D products were superior to comparative products. The results of the clothing pressure measurement indicate that the newly developed sports brassiere's front part had less pressure on upper bust and shoulder areas compared to comparative products as well as showed less pressure on the back side, which shows improved wearing comfort compared to comparative products.

• Journal of Korean Neurosurgical Society
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• v.62 no.5
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• pp.577-585
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• 2019

Objective : Comparing the effects of magnetically controlled growing rod (MCGR) and traditional growing rod (TGR) techniques on the sagittal plane in the treatment of early-onset scoliosis (EOS). Methods : Twelve patients were operated using dual MCGR technique in one center, while 15 patients were operated using dual TGR technique for EOS in another center. Patients' demographic characteristics, complications and radiological measurements such as cobb angle, thoracic kyphosis, lumbar lordosis, T1-S1 range (mm), proximal junctional angle, distal junctional angle, sagittal balance, coronal balance, pelvic incidence, sacral slope and pelvic tilt were assessed and compared in preoperative, postoperative and last follow-up period. Results : Age and sex distributions were similar in both groups. The mean number of lengthening in the MCGR group was 12 (8-15) and 4.8 (3-7) in the TGR group. Two techniques were shown to be effective in controlling the curvature and in the increase of T1-S1 distance. In TGR group, four patients had rod fractures, six patients had screw pull-out and four patients had an infection, whereas three patients had screw pull-out and one patient had infection complications in the MCGR group. Conclusion : There was no significant difference between the two groups in terms of cobb angle, coronal and sagittal balance and sagittal pelvic parameters. MCGR can cause hypokyphosis and proximal junctional kyphosis in a minimum 2-year follow-up period. The implant-related complications were less in the MCGR group. However, larger case groups and longer follow-up periods are required for the better understanding of the superiority of one method on other in terms of complications.

• Bulletin of the Korean Chemical Society
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• v.32 no.4
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• pp.1187-1194
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• 2011

The hydrogen abstraction reaction of $CF_3CH_2CHO$ + OH has been studied theoretically by dual-level direct dynamics method. Two stable conformers, trans- and cis-$CF_3CH_2CHO$, have been located, and there are four distinct OH hydrogen-abstraction channels from t-$CF_3CH_2CHO$ and two channels from c-$CF_3CH_2CHO$. The required potential energy surface information for the kinetic calculation was obtained at the MCG3-MPWB//M06-2X/aug-cc-pVDZ level. The rate constants, which were calculated using improved canonical transitionstate theory with small-curvature tunneling correction (ICVT/SCT) were fitted by a four-parameter Arrhenius equation. It is shown that the reaction proceeds predominantly via the H-abstraction from the -CHO group over the temperature range 200-2000 K. The calculated rate constants were in good agreement with the experimental data between 263 and 358 K.

• 한국연소학회:학술대회논문집
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• 2004.06a
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• pp.42-48
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• 2004

Lean laminar premixed propane and methane flames which were anchored by a hydrogen-pilot flame in a tube were investigated experimentally. The flame shapes were observed by varying mean velocity from 10cm/s to 140cm/s and equivalence ratio from 0.45 to 0.8. In this study, behaviors of flames are divided into five regions such as tail-out, flash-back, flickering, stable and vibrating flames with respect to the mean velocity and the equivalence ratio. Although the flames are unstable in both the flickering and the vibrating region, they have different characteristics such as the frequency, sound generation and creation process of flame curvature. The flickering region exists near the flammability limit and the flame flickers in a frequency of about 10Hz. When flame front is bended, the propane flame front is straightened and the methane flame front is bended more by thermo-diffusive instability. In the vibrating region, the flame vibrates emitting audible sound in a frequency of about 100Hz. In the boundary of vibrating region, the vibration of flame changes between two modes such as single frequency vibration and dual frequency vibration. Increase and decrease of vibration in each mode are determined by thermo-acoustic instability.

• Transactions of the Korean Society of Automotive Engineers
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• v.6 no.4
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• pp.108-120
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• 1998

A theoretical study of three-dimensional unsteady compressible non-reacting flow inside double flow of monolith catalytic converter system attached to 6-cylinder engine was performed for the achievement of performance improvement, reduction of light-off time, and longer service life by improving the flow distribution of pulsating exhaust gases. The differences between unsteady and steady-state flow were evaluated through the numerical computations. To obtains the boundary conditions to a numerical analysis, one dimensional non-steady gas dynamic calculation was also performed by using the method of characteristics in intake and exhaust system. Studies indicate that unsteady representation is necessary because pulsation of gas velocity may affect gas flow uniformity within the monolith. The simulation results also show that the level of flow maldistribution in the monolith heavily depends on curvature and angles of separation streamline of mixing pipe that homogenizes the exhaust gas from individual cylinders. It is also found that on dual flow converter systems, there is severe interactions of each pulsating exhaust gas flow and the length of mixing pipe and junction geometry influence greatly on the degree of flow distribution.

• Korean Journal of Optics and Photonics
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• v.21 no.6
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• pp.247-253
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• 2010

A dual-layer light guide plate (DLGP) was designed and a simulation was done to optimize the structure of the light guide plates used at backlight units while maintaining the luminance, uniformity and viewing angle by reducing the optical sheet. The characteristic of DLGP with prism pattern with curvature on the top surface is simulated and the luminance and uniformity are obtained. In order to improve the uniformity, the V groove prism pattern on the bottom surface was turned by an angle of $90^{\circ}$. In particular, we used the pitch calculation program to select the value of the ratio (Max : Min) between the pitch at the extreme outside and the pitch at the middle, the number of V groove lines and the variance at the bottom pattern of DLGP. After that, the optimum distance between V grooves was determined. For optimizing the DLGP, we examined the uniformity again by changing the number of pattern grooves on the bottom surface of DLGP. As a result of the simulation, we find that the BLU with DLGP has a uniformity of 90.6% and viewing angle $145^{\circ}$.