• Korean Membrane Journal
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• v.9 no.1
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• pp.27-33
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• 2007

PVDF membrane formation via TIPS was performed for PVDF/DBP and PVDF/DMP systems. PVDF/DBP system showed solid-liquid phase separation behavior, while PVDF/DMP system has liquid-liquid phase separation characteristic as well as solid-liquid phase separation characteristic. PVDF contents and cooling conditions had great influence on structure, and the effects of each parameter were examined. Spherulitic structure was obtained due to the dominant PVDF crystallization. Diluent rejected to the outside of spherulite occupied the surface of the PVDF spherulites to result in the microporous spherulite formation and micro-void between spherulites. PVDF/DMP system had competitive solid-liquid and liquid-liquid phase separation depending on the cooling path.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.26 no.12
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• pp.853-857
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• 2013

We design, develope and test a parallel active polymer pen lithography (PPL) device, which consists of individually addressable elastomeric probe tips. The PPL array chip is fabricated using soft lithography method with polydimethylsiloxane (PDMS) material. Individual probe can be pneumatically actuated via a computer controlled interface. We demonstrate parallel writing with 16 individually addressed pens, with each pen producing a different pattern in the same run. The largest proof-of-concept array fabricated is $4{\times}4$ with a spacing of $250{\mu}m$ in both x and y axes.

• The Research Journal of the Costume Culture
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• v.22 no.1
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• pp.158-166
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• 2014

Apparel design is an economic activity to create values for users over the value chain of a product. In this paper, the contribution of apparel design is defined as the enhancement of users' perceived values by improving users' experience of products. In this context, the value of a product corresponds to compensation for experience or a promise for experience of a product. Experience can be sensory or psychological benefits to users. To evaluate the value of apparel design, the researcher identified and analyzed the apparel design parameters affecting users' experience and benefits of products such as macro-, micro-environmental factors, value chain factors, apparel designer factors, and user factors. For an analytical modeling of the values of apparel design, this paper introduces the concept of a utility function from economics. In economics, utility is a measure of desirability or satisfaction that can be correlative to need or desire. The measure of value can be found in the price which a user is willing to pay for the fulfillment or satisfaction of need or desire via the experience of a product.

• Advances in aircraft and spacecraft science
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• v.4 no.6
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• pp.711-727
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• 2017

This article is concerned with a two-dimensional problem of micropolar generalized thermoelasticity for a half-space whose surface is traction-free and the conductive temperature at the surface of the half-space is known. Theory of two-temperature generalized thermoelasticity with phase lags using the normal mode analysis is used to solve the present problem. The formulas of conductive and mechanical temperatures, displacement, micro-rotation, stresses and couple stresses are obtained. The considered quantities are illustrated graphically and their behaviors are discussed with suitable comparisons. The present results are compared with those obtained according to one temperature theory. It is concluded that both conductive heat wave and thermodynamical heat wave should be separated. The two-temperature theory describes the behavior of particles of elastic body more real than one-temperature theory.

• Transactions of the Korean Society of Mechanical Engineers
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• v.11 no.6
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• pp.1036-1043
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• 1987

The objective of this paper is to improve the transient response characteristics of hydraulic servosystem via a reduced-order observer which is modelled based upon the nonlinear hydraulic servosystem. The observer is a second order linear model and implemented using a 8 bit micro-computer. The performance of the observer-based hydraulic servosystem was investigated through the hybrid computer simulations and experiments. The result shows that the reduced-order observer can effectively improve the transient response characteristics of hydraulic servosystem.

• Journal of Ginseng Research
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• v.14 no.2
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• pp.162-166
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• 1990

The climacterium is that phase in the aging precess during which a woman passes from the reproductive to the non-reporductive stage. The signals, such as hot flashes, vaso-motoric disturbances, perspiration, stiff shoulders, emotinal symptoms, are refered to as climacteric disturbances. Treatment of climacteric symptoms centers around estrogen replacement and transfuilizers, but there are many problems to be solved to use these hormones/drugs as far as dossage, duration and complications are concerned. The care of women during the climacteric years should provide relief of distressing symptoms with as high a degree of safety as possible. From this view point, we used red ginseng powder to those patients with high menopausal index successfully. We studied its mechanism of action and proved that red ginseng improved the micro-circulation system via improvement of erythrocyte reformability which enhanced sex steroidgensis consequently.

• Proceedings of the KIEE Conference
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• 2008.10b
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• pp.318-319
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• 2008

In this paper, a steering feel simulator is designed and implemented using a steering wheel with a rotation angle sensor, torque sensor, and an ac motor for the generation of the required torque. The controller in the simulator consists of a 16-bit micro-controller, a D/A converter and A/D converters. The main objective of the controller is to perform torque control where the reference torque is calculated from the torque map for both the vehicle velocity and the wheel sensor cutout. It is shown via the experimentation using the proposed simulator that the simulator output performance can be easily understood for the variation of vehicle parameters or controller parameters.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 1993.04b
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• pp.102-107
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• 1993

The achievable machining accuracy depends upon the level of the micro-engineering, and the dimensional tolerances in the order of 10nm and surface roughness in the order of 1nm are the accuracytargets to be achieved today. Suchrequirements cannot be satisfiedby the conventional machining processes. Single point diamond turning is one of the new techniques which can produce the parts with such accuracy limits. The aims of this thesis are to get a better understanding of the complex cutting process with a diamond tool and, consequently, to develope a predicting modelof a turned surface profile. In order to predict the turned surface profile, a numerical model has been developed. By means of this model, the influences of the cutting conditions, the material properties of the workpiece, the geometry of the cutting tool and the dynamic behaviour of the lathe and their influences via the cutting forces upon the surface roughness have been estimated.

• 한국신재생에너지학회:학술대회논문집
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• 2006.11a
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• pp.433-437
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• 2006

Pt/Nafion self-humidifying membranes for Polymer Electrolyte Membrane Fuel Cell(PEMFC) were synthesized via supercritical-impregnation methods. The Nafion 112 membranes were impregnated with Pt(II)$(acetylacetonate)_2$ from a supercritical carbon dioxide $(scCO_2)$ solution at $80^{\circ}C$ and 30MPa. After the impregnation, the pressure decreased slowly by releasing $CO_2$. And the Pt-impregnated Nafion membrane was converted Pt deposited Nafion membrane by reducing agent, sodium borohydride $(NaBH_4)$ with various concentrations under $50^{\circ}C$ and 2 hours. The prepared Pt-impregnated Nafion (Pt/Nafion) composite membrane were investigated by Electron Prove Micro analysis (EPMA) and X-rat Diffraction analysis (XRD) which showed distribution of Pt particle and Scanning Electron Microscopy (SEM) and Atomic Force Microscopy (AFM) a which revealed morphology of surface of Pt/Nafion composite membrane. The performance of the Pt/Nafion 112 membranes was examined in PEMFC as aself-humidifyin membranes using purpose-built equipment.

• Transactions of the Korean Society of Automotive Engineers
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• v.7 no.6
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• pp.72-81
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• 1999

A nonlinear engine torque and speed control algorithm using throttle angle control is developed with an engine load torque estimation algorithm. Three 3-dimensional nonlinear engine maps as a part of the nonlinear control algorithm are obtained from steady state engine dynamometer tests. An electric throttle actuator is developed using a stepper motor and a 8 bit micro-processor. The speed control and external load estimation algorithm are tested via engine speed control experiments, and show performance good enough for using various engine torque and speed control applications.