• Korea-Australia Rheology Journal
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• v.19 no.3
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• pp.147-156
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• 2007

The orientation and deformation of polymer chains in a confined channel flow has been investigated. The polymer chain was modeled as a Finitely Extensible Nonlinear Elastic (FENE) dumbbell. The Brownian configuration field method was extended to take the interaction between the flow and local chain dynamics into account. Drag and Brownian forces were treated as anisotropic in order to reflect the influence of the wall in the confined flow. Both Poiseuille flow and 4 : 1 contraction flow were considered. Of particular interest was molecular tumbling of polymer chains near the wall. It was strongly influenced by anisotropic drag and high shear close to the wall. We discussed the mechanism of this particular behavior in terms of the governing forces. The dumbbell configuration was determined not only by the wall interaction but also by the flow type of the geometric origin. The effect of extensional flow on dumbbell configuration was also discussed by comparing with the Poiseuille flow.

• Journal of Distribution Research
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• v.10 no.2
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• pp.1-26
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• 2005

The purpose of this study is to identify the consumer factors influencing the channel choice in the brokerage transaction. The 14 consumer factors were extracted from the two perspectives: first, the off-line channel is based on the relational benefits offered by the salespeople, second, the on-line stock exchange is a transaction mediated by the internet technology. The results shows that the channel choice is significantly influenced by the 8 out of 14 consumer factors hypothesized: interpersonal orientation, risk-taking tendency, amount of money invested, price consciousness, time length of internet usage, innovativeness, information privacy sensitivity, intrinsic desire for information. And the results of discriminant analysis shows that three consumer factors-risk-taking tendency, time length of internet usage, and information privacy sensitivity-are most valuable in discriminating off-line vs. on-line customers.

• Design & Manufacturing
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• v.12 no.2
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• pp.27-33
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• 2018

Korea's automobile industry, which has grown rapidly to become the world's fifth-largest automobile producer, To cope with environmental pollution and energy problems in order to prevail competitive edge in global market We are investing a lot of research personnel and costs. Among them, for realizing alternative light weight It is a part of the automobile module system that has achieved the technological development before the breakthrough in the injection molding process in the press process. Door module PNL was the subject of research. The door module PNL is expected to cause warpage before the mold production due to the thin and flat product characteristics and fiber orientation characteristic of the material. In this paper, CAE analysis and reverse correction tool Design. CAE analysis to obtain the results of weld line position, bending position and deformation value Through the correction tool, think3, the original product was modified before the mold production to improve the completeness of the parts. In fiber orientation, the position and size of the cooling channel in the mold, the position and size of the gate, Temperature, pressure, time, and work environment. Compared with the result of CAE analysis, the product that was reverse-corrected by Think3 was manufactured, and injection molding was performed. Injection molding products were tested 24 hours later. 3.5 mm to 7.0 mm, and under the fixed condition, the deviation was from 1.1 mm to 1.5 mm. Unlike the CAE analysis, the deviation of the actual injection pressure and the cooling temperature, the fiber orientation of the material, In order to solve this problem, it is necessary to compare the injection conditions with the database, I knew I had to catch the standard.

• Proceedings of the Korean Vacuum Society Conference
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• 2012.08a
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• pp.230-230
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• 2012

Graphene have showed promising performance as electrodes of organic devices such as organic transistors, light-emitting diodes, and photovoltaic solar cells. In particular, among various organic materials of graphene-based organic devices, pentacene has been regarded as one of the promising organic material because of its high mobility, chemical stability. In the bottom-contact device configuration generally used as graphene based pentacene devices, the morphology of the organic semiconductors at the interface between a channel and electrode is crucial to efficient charge transport from the electrode to the channel. For the high quality morphology, understanding of initial stages of pentacene growth is essential. In this study, we investigate self-assembly of pentacene molecules on graphene formed on a 6H-SiC (0001) substrate by scanning tunneling microscopy. At sub-monolayer coverage, adsorption of pentacene molecules on epitaxial graphene is affected by $6{\times}6$ pattern originates from the underlying buffer layer. And the orientation of pentacene in the ordered structure is aligned with the zigzag direction of the edge structure of single layer graphene. As coverage increased, intermolecular interactions become stronger than molecule-substrate interaction. As a result, herringbone structures the consequence of higher intermolecular interaction are observed.

• Proceedings of the Korean Vacuum Society Conference
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• 2015.08a
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• pp.163-163
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• 2015

The effect of nematic liquid crystal(5CB-4-Cyano-4'-pentylbiphenyl) on the amorphous indium gallium zinc oxide thin film transistors(a-IGZO TFTs) was investigated. Through dropping the 5CB on the a-IGZO TFT's channel layer which is deposited by RF-magnetron sputtering, properties of a-IGZO TFTs was dramatically improved. When drain bias was induced, 5CB molecules were oriented by Freedericksz transition generating positive charges to one side of dipoles. From increment of the capacitance by orientation of liquid crystals, the drain current was increased, and we analyzed these phenomena mathematically by using MOSFET model. Transfer characteristic showed improvement such as decreasing of subthreshold slope(SS) value 0.4 to 0.2 and 0.45 to 0.25 at linear region and saturation region, respectively. Furthermore, in positive bias system(PBS), prevention effect for electron trapping by 5CB liquid crystal dipoles was observed, which showing decrease of threshold voltage shift [(${\delta}V$]_TH) when induced +20V for 1~1000sec at the gate electrode.

• Proceedings of the Korean Vacuum Society Conference
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• 2013.08a
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• pp.274.1-274.1
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• 2013

We report the circumferential alignment of human aortic smooth muscle cells (HASMCs) in an orthogonally micropatterned circular microfluidic channel to form an in vivo-like smooth muscle cell layer. To realize a biomimetic smooth muscle cell layer which is aligned perpendicular to the axis of blood vessel, we first fabricated a half-circular polydimethylsiloxane (PDMS) microchannel by soft lithography using a convex PDMS mold. The orthogonally micro wrinkle patterns were generated inside the half-circular microchannel by stretching-releasing operation under UV irradiation. Upon UV treatment with uniaxial 40 % stretch of a PDMS substrate and releasing process, the microwrinkle patterns perpendicular to the axial direction of the circular microchannel were generated, which could guide the circumferential alignment of HASMCs successfully during cultivation. The analysis of orientation angle, shape index, and contractile protein marker expression indicates that the cultured HASMCs revealed the in vivo-like cell phenotype. Finally, we produced circular microchannels by bonding two half-circular microchannels, and cultured the HASMCs circumferentially with high alignment and viability for 5 days. These results are the first demonstration for constructing an in vivo-like 3D smooth muscle cell layer in the circular microfluidic channel which can provide novel bioassay platforms for in-depth study of HASMC biology and vascular function.

• Journal of Power System Engineering
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• v.18 no.4
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• pp.29-35
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• 2014

Plate heat exchanger are being applied in the field of OTEC (ocean thermal energy conversion) and SWAC (seawater air conditioning) system. This study is to analyze numerically the heat transfer and pressure drop characteristics by using solid works flow simulation in order to offer optimum design data of plate heat exchanger. Plater heat exchanger proposed in this study is four types. The geometric design parameters of plate heat exchanger are a channel space, a flow orientation, a plate array, the flowrate of working fluid and so on. The main results for numerical analysis of plate heat exchangers are summarized as follows. Heat transfer performance for the channel space of 2.4 mm shows the highest value compared to other spaces. And, the Type 4 plate heat exchanger in Table 2 is the highest performance. From the pressure drop characteristics of plate heat exchanger, the channel space of 3.2 mm shows the lowest value. And Type 1 plate heat exchanger in Table 2 is the lowest pressure drop.

• Korean Journal of Metals and Materials
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• v.50 no.12
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• pp.931-937
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• 2012

The microstructure of Cu-15 wt%Ag composites fabricated by equal channel angular pressing (ECAP) with intermediate heat treatment at $320^{\circ}C$ was investigated by transmission electron microscopy (TEM) observations. Ag precipitates with a thickness of 20-40 nm were observed in the eutectic region of the Cu-15 wt%Ag composite solution treated at $700^{\circ}C$ before ECAP. The Cu matrix and Ag precipitates had a cube on cube orientation relationship. ECAPed composites exhibited ultrafine-grained microstructures with the shape and distribution dependent on the processing routes. For route A in which the sample was pressed without rotation between each pass, the Cu and Ag grains were elongated along the shear direction and many micro-twins were observed in elongated Cu grains as well as in Ag filaments. The steps were observed on coherent twin boundaries in Cu grains. For route Bc in which the sample was rotated by 90 degrees after each pass, a subgrain structure with misorientation of 2-4 degree by fragmentation of the large Cu grains were observed. For route C in which the sample was rotated by 180 degrees after each pass, the microstructure was similar to that of the route A sample. However, the thickness of the elongated grains along the shear direction was wider than that of the route A sample and the twin density was lower than the route A sample. It was found that more microtwins were formed in ECAPed Cu-15 wt%Ag than in the drawn sample. Grain boundaries were observed in relatively thick and long Ag filaments in Cu-15 wt%Ag ECAPed by route C, indicating the multi-crystalline nature of Ag filaments.

• Management & Information Systems Review
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• v.30 no.4
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• pp.195-227
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• 2011

There is no doubt that distribution channels and services greatly satisfy consumers' desires. Lots of products and services, stimulate consumers to purchase products to relieve their depressed feeling/stress temporarily, leading them gradually to a shopping addiction. Shopping addiction generates lots of problems, damaging not only consumers themselves but also other consumers and the entire society. Therefore, the purposes of this study were 1) to examine psychological factors that affected addictive shopping orientation of consumers, 2) to explore the effects addictive shopping orientation on the post-purchase emotions(positive emotion/negative emotion), 3) to examine the effect of post-purchase emotions on post-purchase behaviors (repurchasing/refund and exchange/negative word of mouth). 4) the study explored the differences in terms of effects of addictive shopping orientations on post-purchase emotions and behaviors, depending on the retailing channel (online and off line). The study performed a questionnaire survey for female adults older than 18 years old, living Seoul and Pusan areas. By using 404 copies for questionnaires, factor analysis, reliability analysis, and Amos 7.0 were used for the data analysis. It was found that psychological variables, self-esteem, compensatory buying and impulsiveness, had significant effects on addictive shopping orientations. Addictive shopping orientations affect both positive and negative post-purchase emotions in case of off-line shopping. Negative post-purchase emotions have higher impact on the postpurchase behaviors than positive post-purchase emotions.

• Proceedings of the KSME Conference
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• 2000.04a
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• pp.741-744
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• 2000

In general there occur warpage in one way long part. Warpage is caused by differential shrinkage-Orientation Effect, Volumetric Shrinkage Effect, Differential Cooling Effect -over the part. Deco-Top is located at the top of 29"TV set and it's shape is one way long$(626{\times}130mm)$. Material is used transparency ABS resin. So we can't design ribs in this part. And we use film gate to avoid weld line. In these reasons we must develop no ribs and no warpage product. In this study we use MOLDFLOW's software-MF/FLOW, MF/COOL, MF/WARP. Using MF/FLOW, set the flow balance and gate positioning. And we can set cooling channel layout and the optimum processing condition through MF/COOL and MF/WARP. In result we reduced trials and obtained good product.