• Design & Manufacturing
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• v.11 no.3
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• pp.13-18
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• 2017

The injection molding analysis of VCM (Voice Coil Motor) housing for smart phone cameras were performed. We conducted the analysis in terms of injection molding pressure, the formation of weld lines, flow marks, and flow patterns. The goal of the analysis was targeted for the prediction of the optimal gate locations. Because the quality of VCM housing is strongly dependent on the precise control of the camera lens by its nature, we focused on the lens guiding lanes in the VCM housing. We first calculated the maximum injection molding pressure in terms of the filled volumes. The injection molding pressure were calculated within 146MPa at about 90% volume filled. We also investigated the possibility of the occurrence of design-related defects such flow marks, weld lines. Filling patterns regarding the design of the gate locations were delineated to find the weld lines. Throughout the simulations, the final deformations of the lens guiding lanes for the VCM housing were calculated. The deformations distribute ranging from $0.5{\mu}m$ to $2.50{\mu}m$, which were used to find the optimal design of the gates.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.30 no.2 s.245
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• pp.161-169
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• 2006

The spray characteristics of liquid jet in cross flow with variation of injection angle are numerically studied. Numerical analysis was carried out using KIVA code, which was modified to be suitable for simulating liquid jet ejected into cross flow. Wave model and Kelvin-Helmholtz(KH)/Rayleigh-Taylor(RT) hybrid model were used for the purpose of analyzing liquid column, ligament, and the breakup of droplet. Numerical results were compared with experimental data in order to verify the reliability of the physical model. Liquid jet penetration length, volume flux, droplet velocity profile and SMD were obtained. Penetration length increases as flow velocity decreases and injection velocity increases. From the bottom wall, the SMD increases as vertical distance increases. Also the SMD decreases as injection angle increases.

• 한국전산유체공학회:학술대회논문집
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• 2003.08a
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• pp.126-131
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• 2003

A series of computational simulations have been carried out for supersonic flows in a scram jet engine with and without a cavity. Transverse injection of hydrogen, a simplest form of fuel supply, is considered in the present study with the injection pressure varying from 0.5 to 1.5 MPa. The corresponding equivalence ratios are 0.167 - 0.50. The work features detailed resolution of the flow dynamics in the combustor, which was not typically available in most of the Previous studies. In particular, oscillatory flow characteristics are captured at a scale sufficient to identify the underlying physical mechanisms. Much of the flow unsteadiness is related not only to the cavity, but also to the intrinsic unsteadiness in the flowfield. The interactions between shock waves and shear layer may cause a large excursion of flow oscillation. The role of the cavity and injection pressure are examined systematically.

• Analytical Science and Technology
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• v.8 no.4
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• pp.575-582
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• 1995

A new analytical procedure using a serial dual electrode detector was developed for the analysis of amino acids and proteins. Bromine was generated at the upstream electrode and detected by the downstream electrode. The presence of amino acids and proteins was shown to lower the downstream current but with no apparent effect on the upstream current. This indirect mode of detection can be applied to the determination of amino acids and proteins which are electrochemically inactive or too large to be accessible to the electrode surface for electron exchange. The method is shown capable to determine various amino acids (cystine, tyrosine, lysine, tryptophan, glycine, methionine and arginine) and proteins (cytochrome c, hemoglobin, HAS, a-Amylase, Conalbumin I, Catalase and Myglobin) with linear working range for amino acids between $10^{-6}$ to $10^{-3}M$ and total proteins between $10^{-7}$ to $10^{-3}M$. The method has been applied for the analysis of amino acids and total protein in food using Flow Injection Analysis with results obtained comparable to those using the traditional analytical procedure. Use of pulse generation technique was shown to produce a more stable flow injection analysis peaks for repetitive determination than the use of conventional constant current method which showed increase of the background current after determination over 200 minutes. The pulse method was found to give stable baseline even after 400 minutes. Thus, the method is shown able to provide a suitable analytical procedure for automatic analysis of amino acids and proteins in food by flow injection analysis.

• Design & Manufacturing
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• v.6 no.2
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• pp.1-5
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• 2012

Weld line in injection molded part is one of the defects in injection molding process. Weld line deteriorates not only appearance quality but mechanical property. In this study, ABS and PP were used as experimental materials. And weld line length, depth and strength have been examined according to the injection molding conditions. As the results of experimental studies, weld line length increased as flow rate increases for all materials. And the flow rate is most influenced to the creation of weld line length. Also weld line strength increased, as flow rate and melt temperature increase for all materials. The whole experiment results was similar to CAE analysis results.

• 한국금형공학회:학술대회논문집
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• 2008.06a
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• pp.115-119
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• 2008

Weld line in injection molded part is one of the defects in injection molding process. Weld line deteriorates not only appearance quality but mechanical property. In this study, ABS and PP were used as experimental materials. And weld line length, depth and strength have been examined according to the injection molding conditions. As the results of experimental studies, weld line length increased as flow rate increases for all materials. And the flow rate is most influenced to the creation of weld line length. Also weld line strength increased, as flow rate and melt temperature increase for all materials. The whole experiment results was similar to CAE analysis results.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2003.06a
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• pp.784-787
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• 2003

The present work covers three-dimensional flow simulation and deformation analysis of injection molded plastic lenses using solid elements. A numerical scheme to evaluate part deformation has been proposed from the results of injection molding analysis. Proposed scheme has been applied to the injection molding processes of optical plastic lenses: a spherical lens and an aspheric lens for a photo pick-up device. Through the simulation processes. residual stress is estimated and the final deformed patters are obtained for both products. The reliability of the proposed approach has also been verified in comparison with the results of real experiments.

• Journal of the Korean Society of Combustion
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• v.4 no.1
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• pp.141-153
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• 1999

Numerical analysis for the combustion flow in the combustion chamber of incineration system has been carried out in order to acquire the basic design capability of incineration system. Established mathematical model was applied to the performance prediction of the pre-designed combustion chamber of commercial plant. Especially, combustion characteristics and the variation of flow pattern have been deeply discussed in accordance with secondary air injection. Secondary air injection was effective for the turbulent mixing between air and carbon monoxide/volatile matter resulting in considerably reduced CO content at the exit. Secondary air injection was found to be one of the key design parameters because the size of recirculation zone could be changed with the variation of injection characteristics.

• Proceedings of the KSME Conference
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• 2007.05a
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• pp.614-619
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• 2007

The importance of simulation of plastic flow in the injection mold is increasing as the parts are more complex, but the small-scale enterprises can't afford to invest for the infra individually. CAE (Computer Aided Engineering) service was naturally born based on these needs. This paper presents the engineering collaboration model between the large and the small/medium enterprises in the field of injection molds. Based on the engineering collaboration hub and CAE service, small-scale enterprises could research the necessary technology and develop the proper products. The analysis results of CAE are provided by the integrated visualization system on the web. This paper also deals with the delivery shorting process of CAE service for electric/electronic parts which should meet the needs of customers as soon as possible.

• KSBB Journal
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• v.17 no.4
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• pp.339-344
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• 2002

Flow injection analysis technique for monitoring of xylitol concentrations in biological processes has been developed using xylitol oxidase (XYO) immobilized on VA-Epoxy Biosynth carrier. The immobilized XYO cartridge has been integrated into a FIA system with an oxygen electrode and systematically investigated with regards to the factors which can affect the activity of the immobilized XYO, such as pH, temperature, salt concentration etc. The activity of the immobilized XYO increased with the temperature ($19.0 - 29.0^{circ}C$) and sample injection volume ($75-250\muL$) and molarity of potassium phosphate buffer (0.1-1 M), but it reached the highest value at pH 8.5. The XYO-FIA system has been also applied for on-line monitoring of xylitol concentrations in a reactor and showed good operational stability and agreement with off-line data measured with HPLC.